👤 Brooke Gardiner

Protease-Activated Receptor-2 (PAR2) has been implicated through genetic knockout mice with cytokine regulation and arthritis development. Many studies have associated PAR2 with inflammatory conditions (arthritis, airways inflammation, IBD) and key events in tumor progression (angiogenesis, metastasis), but they have relied heavily on the use of single agonists to identify physiological roles for PAR2. However such probes are now known not to be highly selective for PAR2, and thus precisely what PAR2 does and what mechanisms of downstream regulation are truly affected remain obscure. Effects of PAR2 activation on gene expression in Human Embryonic Kidney cells (HEK293), a commonly studied cell line in PAR2 research, were investigated here by comparing 19,000 human genes for intersecting up- or down-regulation by both trypsin (an endogenous protease that activates PAR2) and a PAR2 activating hexapeptide (2f-LIGRLO-NH(2)). Among 2,500 human genes regulated similarly by both agonists, there were clear associations between PAR2 activation and cellular metabolism (1,000 genes), the cell cycle, the MAPK pathway, HDAC and sirtuin enzymes, inflammatory cytokines, and anti-complement function. PAR-2 activation up-regulated four genes more than 5 fold (DUSP6, WWOX, AREG, SERPINB2) and down-regulated another six genes more than 3 fold (TXNIP, RARG, ITGB4, CTSD, MSC and TM4SF15). Both PAR2 and PAR1 activation resulted in up-regulated expression of several genes (CD44, FOSL1, TNFRSF12A, RAB3A, COPEB, CORO1C, THBS1, SDC4) known to be important in cancer. This is the first widespread profiling of specific activation of PAR2 and provides a valuable platform for better understanding key mechanistic roles of PAR2 in human physiology. Results clearly support the development of both antagonists and agonists of human PAR2 as potential disease modifying therapeutic agents. Show less

Sulfate plays an essential role in human growth and development, and its circulating levels are maintained by the renal Na+-SO42- cotransporter, NaS1. We previously generated a NaS1 knockout (Nas1-/-) mouse, an animal model for hyposulfatemia, that exhibits reduced growth and liver abnormalities including hepatomegaly. In this study, we investigated the hepatic gene expression profile of Nas1-/- mice using oligonucleotide microarrays. The mRNA expression levels of 92 genes with known functional roles in metabolism, cell signaling, cell defense, immune response, cell structure, transcription, or protein synthesis were increased (n = 51) or decreased (n = 41) in Nas1-/- mice when compared with Nas1+/+ mice. The most upregulated transcript levels in Nas1-/- mice were found for the sulfotransferase genes, Sult3a1 (approximately 500% increase) and Sult2a2 (100% increase), whereas the metallothionein-1 gene, Mt1, was among the most downregulated genes (70% decrease). Several genes involved in lipid and cholesterol metabolism, including Scd1, Acly, Gpam, Elov16, Acsl5, Mvd, Insig1, and Apoa4, were found to be upregulated (> or = 30% increase) in Nas1-/- mice. In addition, Nas1-/- mice exhibited increased levels of hepatic lipid (approximately 16% increase), serum cholesterol (approximately 20% increase), and low-density lipoprotein (approximately 100% increase) and reduced hepatic glycogen (approximately 50% decrease) levels. In conclusion, these data suggest an altered lipid and cholesterol metabolism in the hyposulfatemic Nas1-/- mouse and provide new insights into the metabolic state of the liver in Nas1-/- mice. Show less

The neuronal ceroid lipofuscinoses (NCLs) are a group of autosomal recessive neurodegenerative diseases of childhood. CLN6, the gene mutated in variant late infantile NCL (vLINCL), was recently cloned. We report the identification of eight further mutations in CLN6 making a total of 18 reported mutations. These mutations include missense, nonsense, small deletions or insertions, and two splice-site mutations. Ten mutations affect single amino acids, all of which are conserved across vertebrate species. Minor differences in the pattern of disease symptom evolution can be identified. One patient with a more protracted disease progression was a compound heterozygote for a missense mutation and an unidentified mutation. Fifteen CLN6 mutations occur in one or two families only, and families from the same country do not all share the same mutation. Unlike NCLs caused by mutations in CLN1, CLN3, CLN5, and CLN8, there is no major founder mutation in CLN6. However, one mutation (E72X) is significantly more common in patients from Costa Rica than two other mutations present in that same population. In addition, a 1-bp insertion (c.316insC) is associated with families from Pakistan and I154del may be common in Portugal. A group of Roma Gypsy families from the Czech Republic share two disease-associated haplotypes, one of which is also present in a Pakistani family, consistent with the proposed migration of the Roma from the Indian subcontinent 1,000 years ago. All mutations are recorded in the NCL Mutation Database together with their country of origin for use in the development of rapid screening assays to confirm diagnosis and to facilitate carrier testing appropriate to a population. Show less

One variant form of late infantile neuronal ceroid lipofuscinosis (LINCL) is found predominantly within the Turkish population (CLN7). Exclusion mapping showed that CLN7 was not an allelic variant of known NCL loci (CLN1, CLN2, CLN3, CLN5 or CLN6). Using the method of homozygosity mapping, a genome-wide search was undertaken and a total of 358 microsatellite markers were typed at an average distance of about 10 cM. A region of shared homozygosity was identified on chromosome 8p23. This telomeric region contained the recently identified CLN8 gene. A missense mutation in CLN8 causes progressive epilepsy with mental retardation (EPMR) or Northern epilepsy, which has so far been reported only from Finland and is now classified as an NCL. The mouse model mnd has been shown to carry a 1 bp insertion in the orthologous Cln8 gene. Statistically significant evidence for linkage was obtained in this region, with LOD scores > 3, assuming either homogeneity or heterogeneity. Flanking recombinants defined a critical region of 14 cM between D8S504 and D8S1458 which encompasses CLN8. This suggests that Turkish variant LINCL, despite having an earlier onset and more severe phenotype, may be an allelic variant of Northern epilepsy. However mutation analysis has not so far identified a disease causing mutation within the coding or non-coding exons of CLN8 in the families. The Turkish variant LINCL disease-causing mutation remains to be delineated. Show less

The neuronal ceroid lipofuscinoses (NCLs) are a group of inherited neurodegenerative disorders characterized by the presence of autofluorescent lipopigment in neurons and other cell types. The childhood onset types display autosomal recessive inheritance. Naturally occurring animal NCLs have been described in many species including mouse, sheep and dog. In the last decade major advances have occurred in the molecular genetic analysis of the NCLs. Six disease gene loci have been mapped, and five disease genes have been isolated. Two of these encode lysosomal enzymes: CLN1 encodes palmitoyl-protein thioesterase (PPT), and CLN2 encodes tripeptidyl peptidase 1 (TPP1). The remaining three, CLN3, CLN5 and CLN8 encode putative membrane proteins of unknown function. The murine orthologue of CLN8 causes motor neuron degeneration (mnd), a mouse model of NCL. These advances have revolutionized diagnosis and classification, but a unified theory of pathogenesis and effective treatment remain elusive. Show less

Batten disease, a degenerative neurological disorder with juvenile onset, is the most common form of the neuronal ceroid lipofuscinoses. Mutations in the CLN3 gene cause Batten disease. To facilitate studies of Batten disease pathogenesis and treatment, a murine model was created by targeted disruption of the Cln3 gene. Mice homozygous for the disrupted Cln3 allele had a neuronal storage disorder resembling that seen in Batten disease patients: there was widespread and progressive intracellular accumulation of autofluorescent material that by EM displayed a multilamellar rectilinear/fingerprint appearance. Inclusions contained subunit c of mitochondrial ATP synthase. Mutant animals also showed neuropathological abnormalities with loss of certain cortical interneurons and hypertrophy of many interneuron populations in the hippocampus. Finally, as is true in Batten disease patients, there was increased activity in the brain of the lysosomal protease Cln2/TPP-1. Our findings are evidence that the Cln3-deficient mouse provides a valuable model for studying Batten disease. Show less

Among the epilepsies, the progressive myoclonus epilepsies (PMEs) form a heterogeneous group of rare diseases characterized by myoclonus, epilepsy, and progressive neurologic deterioration, particularly dementia and ataxia. The success of the Human Genome Project and the fact that most PMEs are inherited through a mendelian or mitochondrial mode have resulted in important advances in the definition of the molecular basis of PME. The gene defects for the most common forms of PME (Unverricht-Lundborg disease, the neuronal ceroid lipofuscinoses, Lafora disease, type I sialidosis, and myoclonus epilepsy with ragged-red fibers) have been either identified or mapped to specific chromosome sites. Unverricht-Lundborg disease has been shown to be caused by mutations in the gene that codes for cystatin B, an inhibitor of cysteine protease. The most common mutation in Unverricht-Lundborg disease is an expansion of a dodecamer repeat located in a noncoding region upstream of the transcription start site of the cystatin B gene, making it the first human disease associated with instability of a dodecamer repeat. Juvenile neuronal ceroid lipofuscinosis is caused by mutations in the CLN3 gene, a gene of unknown function that encodes a 438-amino-acid protein of possible mitochondrial location. Other forms of neuronal ceroid lipofuscinosis that occur as PME and Lafora disease have been mapped by means of linkage analysis, but the corresponding gene defects remain unknown. Sialidosis has been shown to be caused by mutations in the sialidase gene, and myoclonus epilepsy with ragged-red fibers is well known to be caused by mutations in the mitochondrial gene that codes for tRNA(Lys). How the different PME gene defects described produce the various PME phenotypes, including epileptic seizures, remains unknown. The development of animal models that bear these mutations is needed to increase our knowledge of the basic mechanisms involved in the PMEs. This knowledge should lead to the development of new and effective forms of therapy, which are especially lacking for the PMEs. Show less

The neuronal ceroid lipofuscinoses (NCLs) are a group of inherited neurodegenerative disorders characterised by the accumulation of autofluorescent storage material in neurons and other cell types. The clinical features include visual impairment, progressive myoclonic epilepsy, and cognitive decline reflecting progressive neurodegeneration. The NCLs are subdivided into several subtypes according to age of onset, clinical course, and ultrastructure of the storage material. The molecular genetic basis of this group of disorders has recently been clarified. Mutations in the gene encoding a lysosomal enzyme, palmitoyl protein thioesterase (PPT), cause infantile NCL (locus CLN1 on chromosome 1p32) or Haltia-Santavuori disease. This Finnish disease is characterised ultrastructurally by granular osmiophilic deposits (GRODs). Juvenile-onset NCL with GRODs also is caused by mutations in PPT. Classic late-infantile NCL (Jansky-Bielschowsky disease) is caused by mutations in a gene encoding a pepstatin-insensitive lysosomal peptidase (CLN2 on chromosome 11p15), and juvenile-onset NCL (Batten disease) is caused by mutations in a gene encoding a 438-amino-acid membrane protein (CLN3 on chromosome 16p12) of unknown function. A locus for Finnish variant late-infantile NCL, CLN5, has been mapped to chromosome 13q22 and a locus for variant late-infantile NCL, CLN6, to chromosome 15q21-23. These and further advances will allow the molecular basis of the NCLs to be elucidated and may lead to new strategies for diagnosis and treatment. Show less

JNCL is a neurodegenerative disease of childhood caused by mutations in the CLN3 gene. A mouse model for JNCL was created by disrupting exons 1-6 of Cln3, resulting in a null allele. Cln3 null mice appear clinically normal at 5 months of age; however, like JNCL patients, they exhibit intracellular accumulation of autofluorescent material. A second approach will generate mice in which exons 7 and 8 of Cln3 are deleted, mimicking the common mutation in JNCL patients. Show less

To correlate the phenotypes with the genotypes of 10 Finnish juvenile neuronal ceroid lipofuscinosis (JNCL; late-onset Batten disease) patients who all are compound heterozygotes for the major 1.02-kb deletion in the CLN3 gene. The mutations on the non-1.02-kb deletion chromosomes were screened in 6 patients; in the other 4 patients the mutations were known (one affecting a splice site, two missense mutations, and one deletion of exons 10 through 13). Clinical features were examined, and MRI, MRS, somatosensory evoked magnetic field (SEF), and overnight polysomnography (PSG) studies were performed. A novel deletion of exons 10 through 13 was found in 6 patients belonging to three families. In the patients carrying the deletions of exons 10 through 13 the clinical course of the disease was fairly similar. Variation was greatest in the time course to blindness. In these patients the mental and motor decline was slower than in classic JNCL, but more severe than in the two patients with missense mutations in exons 11 and 13. MRI showed brain atrophy in 4 patients. One patient had hyperintense periventricular white matter, otherwise brain signal intensities were normal. SEFs were enhanced in patients older than 14 years, whereas in PSG all but the youngest 6-year-old patient showed epileptiform activity in slow-wave sleep. JNCL can manifest as at least three different phenotypes: classic, delayed classic, and protracted JNCL with predominantly ocular symptoms. Finnish compound heterozygotes have the delayed classic or the protracted form of JNCL. Show less

Batten disease (juvenile-onset neuronal ceroid lipofuscinosis [JNCL]) is an autosomal recessive condition characterized by accumulation of lipopigments (lipofuscin and ceroid) in neurons and other cell types. The Batten disease gene, CLN3, was recently isolated, and four disease-causing mutations were identified, including a 1.02-kb deletion that is present in the majority of patients (The International Batten Disease Consortium 1995). One hundred eighty-eight unrelated patients with JNCL were screened in this study to determine how many disease chromosomes carried the 1.02-kb deletion and how many carried other mutations in CLN3. One hundred thirty-nine patients (74%) were found to have the 1.02-kb deletion on both chromosomes, whereas 49 patients (41 heterozygous for the 1.02-kb deletion) had mutations other than the 1.02-kb deletion. SSCP analysis and direct sequencing were used to screen for new mutations in these individuals. Nineteen novel mutations were found: six missense mutations, five nonsense mutations, three small deletions, three small insertions, one intronic mutation, and one splice-site mutation. This report brings the total number of disease-associated mutations in CLN3 to 23. All patients homozygous for mutations predicted to give rise to truncated proteins were found to have classical JNCL. However, a proportion of the patients (n = 4) who were compound heterozygotes for a missense mutation and the 1.02-kb deletion were found to display an atypical phenotype that was dominated by visual failure rather than by severe neurodegeneration. All missense mutations were found to affect residues conserved between the human protein and homologues in diverse species. Show less

The childhood neuronal ceroid lipofuscinoses (NCLs) are a group of autosomal recessive neurodegenerative disorders characterised by progressive visual failure, neurodegeneration, epilepsy and the accumulation of an autofluorescent lipopigment in neurones and other cells. Three main subtypes have been identified according to age of onset, clinical features and ultrastructural morphology. These are infantile NCL (INCL; CLN1), classical late infantile NCL (LINCL; CLN2) and juvenile NCL (JNCL; CLN3). Several atypical forms of late infantile NCL (LINCL) have also been described including a Finnish variant LINCL (CLN5). The CLN2 gene has been excluded from the CLN1, CLN3 and CLN5 loci. A genome search was initiated using a homozygosity mapping strategy in five classical LINCL and two variant LINCL consanguineous families. A common region of homozygosity was identified on chromosome 11p15 in two of the classical families. Analysis of a further 33 classical LINCL families supported linkage in this region (Zmax = 3.07 at theta = 0.06 at D11S1338). A common region of homozygosity was also observed on chromosome 15q21-23 in the two variant LINCL families. Extension of the analysis to include a further seven families of identical ultrastructural phenotype established linkage to this region (Zmax = 6.00 at theta = 0.00 at D15S1020). Show less

We recently cloned a cDNA for CLN3, the gene for juvenile-onset neuronal ceroid lipofuscinosis or Batten disease. To resolve the genomic organization we used a cosmid clone containing CLN3 to sequence the entire gene in addition to 1.1 kb 5' of the start of the published CLN3 cDNA and 0.3 kb 3' to the polyadenylation site. CLN3 is organized into at least 15 exons spanning 15 kb and ranging from 47 to 356 bp. The 14 introns vary from 80 to 4227 bp, and all exon/intron junction sequences conform to the GT/AG rule. Numerous repetitive Alu elements are present within the introns and 5'- and 3'-untranslated regions. The 5' region of the CLN3 gene contains several potential transcription regulatory elements but no consensus TATA-1 box was identified. CLN3 is homologous to 27 deposited human ESTs, and sequence comparisons suggest alternative splicing of the gene and the existence of transcribed sequences upstream to the start of the published CLN3 cDNA. Show less

A number of variant forms of the neuronal ceroid lipofuscinoses (NCL) have been described and remain unmapped. The genes for infantile (CLN1), juvenile (CLN3) and Finnish-variant late-infantile (CLN5) have previously been mapped to chromosome regions 1p32, 16p12 and 13q21.1-32 respectively. The locus for a variant form of juvenile onset NCL characterised by cytosomal granular osmiophilic deposits (GROD) has been excluded from the CLN3 region of chromosome 16. This study describes the outcome of genetic linkage analysis in four families with this variant at the loci for the CLN1 and CLN5 genes. Using highly informative microsatellite markers tightly linked to the CLN5 locus we have excluded the JNCL variant with GROD from this region. Marker typing across the CLN1 region suggests that JNCL with GROD may be an allelic variant of infantile NCL. Show less

A strategy for detection of mutations in CLN3, the gene for Batten disease or juvenile onset neuronal ceroid lipofuscinosis, has been devised using a technique which detects conformation polymorphisms and direct sequencing of genomic DNA fragments. We define two mutations found uniquely in Finnish patients, one a large deletion (2.8 kb), the other a point mutation affecting the 5'splice donor site of an intron. Show less

The genomic sequence of the human CLN3 gene, which is defective in juvenile onset neuronal ceroid lipofuscinosis (Batten disease) is being delineated using a variety of methods. A Saccharomyces cerevisiae gene, YHC3 (for Yeast Homologue to human CLN3), which is highly similar to the human disease gene, has been identified by computer-aided homology searching. Topology predictions indicate the CLN3 protein contains six transmembrane segments. Most similarity between the human and yeast proteins lies either in the transmembrane segments or along one face of the predicted protein structure. Show less

In an attempt to understand the molecular nature of Batten disease, we have examined the amino acid sequence of the affected CLN3 gene product (The International Batten Disease Consortium (1995) Cell 82, 949-957) and the site-specific mutations which give rise to the biological defect. Homology searches and molecular modeling have led to the development of a model for the folding and disposition of the protein, possibly within a mitochondrial membrane. High homology with a yeast protein of unknown function suggests a strong evolutionary conservation of function. We speculate that a possible role for the protein may be in chaperoning the folding/unfolding or assembly/ disassembly of other proteins, specifically subunit c of the mitochondrial ATP synthase complex. Show less

Batten disease, or the juvenile form of neuronal ceroid lipofuscinosis, is an autosomal recessive neurodegenerative disorder manifesting with progressive blindness, seizures, and dementia, leading to an early death. The CLN3 locus which is involved in Batten disease had been localized to chromosome 16p11.2. Linkage disequilibrium has been observed between CLN3 and polymorphic microsatellite markers D16S288, D16S299, and D16S298, making carrier detection and prenatal diagnosis by haplotype analysis possible. For the purpose of carrier detection, haplotypes from Dutch Batten patients and their families were constructed. Most patients share the same D16S298 allele, suggesting the presence of a founder effect in the Dutch population. In a large inbred Dutch family, in which Batten disease occurs with high frequency, haplotype analysis has been carried out with high accuracy for carrier detection. Show less

CLN3 has been mapped genetically to 16p12, to the interval between D16S288 and D16S383, a sex-averaged genetic distance of 2.1 cM. Analysis of disease haplotypes for four microsatellite markers in this interval, D16S288, D16S299, D16S298, and SPN, has shown significant allelic association between one allele at each of these loci and CLN3. All four of the associated markers were used as nucleation sites in the isolation of genomic clones (YACs). A contig was assembled which contains 3 of the 4 associated markers and which confirmed the relative order of these markers. Marker D16S272 has been located on the physical map between D16S288 and D16S299. Restriction mapping has demonstrated the location of possible CpG islands. One gene, STP, has been localised on the YAC contig proximal to D16S298 and is therefore a candidate for CLN3. Other genes, including IL4R, SGLT2, and UQCRC2, have been excluded from this region. Show less

The gene for Batten disease (juvenile-onset neuronal ceroid lipofuscinosis, or Spielmeyer-Sjögren disease), CLN3, maps to 16p11.2-12.1. Four microsatellite markers--D16S288, D16S299, D16S298, and SPN--are in strong linkage disequilibrium with CLN3 in 142 families from 16 different countries. These markers span a candidate region of approximately 2.1 cM. CLN3 is most prevalent in northern European populations and is especially enriched in the isolated Finnish population, with an incidence of 1:21,000. Linkage disequilibrium mapping was applied to further refine the localization of CLN3 in 27 Finnish families by using linkage disequilibrium data and information about the population history of Finland to estimate the distance of the closest markers from CLN3. CLN3 is predicted to lie 8.8 kb (range 6.3-13.8 kb) from D16S298 and 165.4 kb (132.4-218.1 kb) from D16S299. Enrichment of allele "6" at D16S298 (on 96% of Finnish and 92% of European CLN3 chromosomes) provides strong evidence that the same major mutation is responsible for Batten disease in Finland as in most other European countries and that it is therefore not a Finnish mutation. Genealogical studies show that Batten disease is widespread throughout the densely populated regions of Finland. The ancestors of two Finnish patients carrying rare alleles "3" and "5" at D16S298 in heterozygous form originate from the southwestern coast of Finland, and these probably represent other foreign mutations. Analysis of the number and distribution of CLN3 haplotypes from 12 European countries provides evidence that more than one mutation has arisen in Europe. Show less

The cytosolic phenol sulphotransferase gene (STP) was mapped to a region of chromosome 16, within the interval defined by human-rodent somatic cell hybrid breakpoints CY160(D) and CY12, which contains FRA16E. YAC and cosmid clones from this 16p interval were screened for the presence of STP. Two non-overlapping cosmid contigs were identified which contain STP-like sequences. Sequencing of these STP-like sequences confirmed that STP is contained within contig 343.1 and maps proximal to FRA16E, and that a related sulphotransferase STM, encoding the catecholamine-sulphating enzyme, is contained within contig 55.4 and maps to the adjacent hybrid interval CY12-CY180A. Thus two phenol sulphotransferase genes (STP and STM) have been finely localised to chromosome 16p12.1-p11.2, to the same region as CLN3, the gene for Batten disease. Both genes are therefore candidate genes for Batten disease. Show less

The neuronal ceroid lipofuscinoses (NCLs) are a group of inherited neurodegenerative disorders characterized by the accumulation of autofluorescent lipopigment in neurons and other cell types. The biochemical basis of these diseases is unknown. Three main childhood forms are recognized: infantile (Santavuori-Haltia disease, CLN1), late infantile (Jansky-Bielschowsky disease, CLN2), and juvenile (Spielmeyer-Vogt-Sjögren, Batten disease, CLN3). The CLN1 gene has been mapped to chromosome 1p and CLN3 to chromosome 16p by linkage analysis (1, 2). The gene locus causing the classical late infantile form (CLN2) has not yet been mapped but has been excluded from both CLN1 and CLN3 loci (8). About 10% of NCL cases have atypical clinical features with most of these resembling the late infantile form. Show less

Batten disease, or neuronal ceroid-lipofuscinosis (CLN) comprises a group of inherited neurodegenerative disorders characterized by the accumulation of autofluorescent lipopigment in neurones. The three main childhood varieties--infantile (CLN1), late-infantile (CLN2) and juvenile (CLN3)--manifest autosomal recessive inheritance. The basic biochemical defect remains unknown. The strategy of positional cloning is being pursued to elucidate the molecular basis of Batten disease. The infantile disease locus (CLN1) has been mapped by linkage analysis to human chromosome 1p32, and the juvenile disease locus (CLN3) to human chromosome 16p12. In each case marker loci in strong linkage disequilibrium with the disease loci have been identified. Locus heterogeneity between classical late-infantile CLN (CLN2) and both CLN1 and CLN3 has been demonstrated. Work is in progress to clone CLN1 and CLN3 and to map CLN2. Identification of linked markers has provided a new approach to prenatal diagnosis. The methodology exists for positional cloning of these genes and elucidation of the molecular genetic basis of the ceroid lipofuscinoses. Show less

The ceroid-lipofuscinoses are a group of inherited neurodegenerative disorders characterised by the accumulation of autofluorescent lipopigment in neurones and other cell types. The underlying biochemical defect is unknown. Juvenile onset neuronal ceroid lipofuscinosis (Batten disease; Spielmeyer-Vogt disease) is an autosomal recessive trait. Linkage studies were undertaken to determine the location of the Batten disease (CLN3) mutation. Studies were carried out on 205 members of 42 families in which there were 76 affected individuals. Families originated from 7 North European countries and Canada. Serum samples from 23 families, including a total of 48 affected children, were tested for a set of "classical markers." A positive lod score was found with the haptoglobin (Hp) system. The combined male and female maximum lod score was 3.00 at theta = 0.00 and theta = 0.26, respectively. This provided an indication of localisation to the long arm of chromosome 16. Linkage analysis was then carried out in 42 families using DNA markers for loci on human chromosome 16. The maximal lod score between Batten disease and the locus D16S148 calculated for combined sexes was 6.05. No recombinants were observed. Multilocus analysis using 5 loci indicated the most likely order to be HP-D16S151-D16S150-CLN3-D16S148-D16S147. Work is in progress to refine the genetic and physical localisation of the Batten disease gene using additional markers in this region and a panel of somatic cell hybrids. Methods are now available which should allow the gene to be isolated and characterised. Show less

The neuronal ceroid lipofuscinoses comprise a group of inherited neurodegenerative disorders characterized by the accumulation of autoflourescent lipopigment in neurones and other cell types. Three main childhood sub-types occur: infantile (Haltia-Santavouri disease, locus CLN1), late-infantile (Jansky-Bielschowsky disease, locus CLN2) and juvenile (Spielmeyer-Sjogren-Vogt, Batten disease, locus CLN3). Inheritance is autosomal recessive. The basic biochemical defect remains unknown. The infantile disease Iocus (CLN1) has been mapped to human chromosome 1p32 and the juvenile disease Iocus (CLN3) to human chromosome 16p12 by linkage analysis. Marker loci in strong allelic association with the disease loci have been identified in each case and haplotype analysis suggests a founder mutation for CLN1 and CLN3. Classical late-infantile disease (CLN2) has been shown not to be an allelic variant of either CLN1 or CLN3. Identification of linked markers has provided a new method for pre-natal diagnosis. Work is in progress to clone CLN1 and CLN3 and to map CLN2. This will allow elucidation of the molecular genetic basis of the neuronal ceroid lipofuscinoses. Show less

The ceroid-lipofuscinoses are a group of inherited neurodegenerative disorders characterized by the accumulation of autofluorescent lipopigment in neurons and other cell types. The underlying biochemical defect is unknown. Batten disease (Spielmeyer-Vogt disease, juvenile onset neuronal ceroid-lipofuscinosis) displays autosomal recessive inheritance. Genetic linkage studies were undertaken to determine the chromosomal location of the Batten disease mutation (CLN3). Following identification of linkage to the haptoglobin locus, linkage analysis has been carried out in 42 families by using DNA markers for loci on the long arm of human chromosome 16. The maximal lod score between Batten disease and the locus D16S148 calculated for combined sexes is 6.05 at a recombination fraction theta = 0.00. Multilocus analysis using five loci indicated the most likely order to be HP-D16S151-D16S150-CLN3-D16S148-D16S147. The maximal location score for CLN3 was 48 (equivalent to a lod score of 10.4) in that interval within this fixed marker map. Show less