👤 Khalid Rahman

Mutations in the X-linked androgen receptor (AR) gene cause complete androgen insensitivity syndrome (CAIS). CAIS may cause congenital sexual development disorder, which frequently develops into testicular tumors. Here, we describe a novel splice-site intron 1 mutation in AR leading to improper splicing and AR protein absence in CAIS gonads. We characterized a patient's postpubertal gonadal steroidogenic enzyme expression profile. Localization of both CYP11A1 and CYP17A1 enzymes was restricted to both Leydig tumor cells and adjacent to tumor gonadal tissues. Sertoli cells of the CAIS gonad showed abundant HSD17B3 protein, which is an adult Leydig cell marker that enables the conversion of androstenedione to testosterone. Such HSD17B3 expression is typical for fetal-type Sertoli cells in rodents. The postpubertal CAIS gonad of our patient was completely devoid of androgen signaling pathway activity. Plausibly, the postpubertal Leydig cells consisted of two distinct cell populations: postpubertal fetal-type Leydig cells that persisted as androgen-independent cells and immature adult Leydig cells that failed to differentiate. Taken together, in this CAIS postpubertal testis, both Leydig and fetal-type Sertoli cells participated in testosterone production. Our results indicate the importance of molecular analysis as well as the characterization of steroidogenic enzyme profiling in the CAIS patient's gonad. Show less

Precise spatiotemporal regulation of splicing is mediated by splicing cis-elements on pre-mRNA. Single-nucleotide variations (SNVs) affecting intronic cis-elements possibly compromise splicing, but no efficient tool has been available to identify them. Following an effect-size analysis of each intronic nucleotide on annotated alternative splicing, we extracted 105 parameters that could affect the strength of the splicing signals. However, we could not generate reliable support vector regression models to predict the percent-splice-in (PSI) scores for normal human tissues. Next, we generated support vector machine (SVM) models using 110 parameters to directly differentiate pathogenic SNVs in the Human Gene Mutation Database and normal SNVs in the dbSNP database, and we obtained models with a sensitivity of 0.800±0.041 (mean and s.d.) and a specificity of 0.849±0.021. Our IntSplice models were more discriminating than SVM models that we generated with Shapiro-Senapathy score and MaxEntScan::score3ss. We applied IntSplice to a naturally occurring and nine artificial intronic mutations in RAPSN causing congenital myasthenic syndrome. IntSplice correctly predicted the splicing consequences for nine of the ten mutants. We created a web service program, IntSplice (http://www.med.nagoya-u.ac.jp/neurogenetics/IntSplice) to predict splicing-affecting SNVs at intronic positions from -50 to -3. Show less

The genetic basis of familial hypertrophic cardiomyopathy (HCM) is well described, but the relation between genotype and clinical phenotype is still poorly characterised. To summarise and critically review the current literature on genotype-phenotype associations in patients with HCM and to perform a meta-analysis on selected clinical features. PubMed/Medline was searched up to January 2013. Retrieved articles were checked for additional publications. Observational, cross-sectional and prospectively designed English language human studies that analysed the relationship between the presence of mutations in sarcomeric protein genes and clinical parameters. The pooled analysis was confined to studies reporting on cohorts of unrelated and consecutive patients in which at least two sarcomere genes were sequenced. A random effect meta-regression model was used to determine the overall prevalence of predefined clinical features: age at presentation, gender, family history of HCM, family history of sudden cardiac death (SCD), and maximum left ventricular wall thickness (MLVWT). The I(2) statistic was used to estimate the proportion of total variability in the prevalence data attributable to the heterogeneity between studies. Eighteen publications (corresponding to a total of 2459 patients) were selected for the pooled analysis. The presence of any sarcomere gene mutation was associated with a younger age at presentation (38.4 vs 46.0 years, p<0.0005), a family history of HCM (50.6% vs 23.1%, p<0.0005), a family history of SCD (27.0% vs 14.9%, p<0.0005) and greater MLVWT (21.0 vs 19.3 mm, p=0.03). There were no differences when the two most frequently affected genes, MYBPC3 and MYH7, were compared. A total of 53 family studies were also included in the review. These were characterised by pronounced variability and the majority of studies reporting on outcomes analysed small cross-sectional cohorts and were unsuitable for pooled analyses. The presence of a mutation in any sarcomere gene is associated with a number of clinical features. The heterogeneous nature of the disease and the inconsistency of study design precludes the establishment of more precise genotype-phenotype relationships. Large scale studies examining the relation between genotype, disease severity, and prognosis are required. Show less

Neuronal ceroid lipofuscinosis (NCL) is a neurodegenerative disease caused by a number of different genes. A mutational analysis of the feline CLN3 gene was performed in a cat with NCL that had vacuolated lymphocytes, which is a feature of human NCL caused by defects of the CLN3 gene. To determine the candidate gene(s) responsible for this case, NCL-specific ultrastructures of storage materials were analysed. A sequence analysis indicated that the CLN3 gene was not likely to be responsible for this case of feline NCL because no deleterious mutation was detected. An ultrastructural analysis did not reveal any candidate gene because of inconsistency with any pattern found in human NCL. These findings suggest that the diagnostic criteria for human NCL are not directly applicable to feline NCL. Show less

Pancreatic endocrine neoplasms (PENs) are rare, mostly well-differentiated endocrine neoplasms, whose biology has been poorly characterized. Global expression microarrays can document abnormal pathways that impact on tumorigenesis and disease progression. RNA was extracted from eight well-differentiated PENs and three highly enriched pancreatic islet cell samples (80-90% purity), and examined using the Affymetrix U133A oligonucleotide microarray. Microarray data were normalized using dCHIP for identification of differentially expressed genes. PEN tissue microarrays were constructed from 53 archival PENs for immunohistochemical validation of microarray data. Sixty-six transcripts were overexpressed > or =3-fold in PENs compared with normal islet cells, including putative oncogenes (MLLT10/AF10), growth factors [insulin-like growth factor-binding protein 3 (IGFBP3)], cell adhesion and migration molecules (fibronectin), and endothelial elements (MUC18/MelCAM and CD31). A total of 119 transcripts were underexpressed < or =3-fold in PENs compared with normal islet cells, including cell cycle checkpoint proteins (p21/Cip1), the MIC2 (CD99) cell surface glycoprotein, putative metastasis suppressor genes (NME3), and junD, a MEN1-regulated transcription factor. Using PEN tissue microarrays, we confirmed the differential up-regulation of IGFBP3 (70%) and fibronectin (22%) and differential down-regulation of p21 (46%) and MIC2 (CD99; 91%) in PENs versus normal pancreatic islets. IGFBP3 overexpression was significantly more common in metastatic (93%) versus primary PEN lesions (60%), P=0.022. Fibronectin overexpression demonstrated a trend toward significance in lymphatic PEN metastases (55%) compared with primary PEN lesions (24%; P=0.14). Global expression analysis provides insight into tumorigenic pathways in PENs and may identify potential prognostic and therapeutic markers for these uncommon neoplasms. Show less