👤 Tony Frugier

The neuronal ceroid lipofuscinoses (NCLs, Batten disease) are a group of fatal recessively inherited neurodegenerative diseases of humans and animals characterised by common clinical signs and pathology. These include blindness, ataxia, dementia, behavioural changes, seizures, brain and retinal atrophy and accumulation of fluorescent lysosome derived organelles in most cells. A number of different variants have been suggested and seven different causative genes identified in humans (CLN1, CLN2, CLN3, CLN5, CLN6, CLN8 and CTSD). Animal models have played a central role in the investigation of this group of diseases and are extremely valuable for developing a better understanding of the disease mechanisms and possible therapeutic approaches. Ovine models include flocks of affected New Zealand South Hampshires and Borderdales and Australian Merinos. The ovine CLN6 gene has been sequenced in a representative selection of these sheep. These investigations unveiled the mutation responsible for the disease in Merino sheep (c.184C>T; p.Arg62Cys) and three common ovine allelic variants (c.56A>G, c.822G>A and c.933₉₃₄insCT). Linkage analysis established that CLN6 is the gene most likely to cause NCL in affected South Hampshire sheep, which do not have the c.184C>T mutation but show reduced expression of CLN6 mRNA in a range of tissues as determined by real-time PCR. Lack of linkage precludes CLN6 as a candidate for NCL in Borderdale sheep. Show less

The neuronal ceroid lipofuscinoses (NCLs, Batten disease) are recessively inherited neurodegenerative disorders that affect humans and other animals, characterised by brain atrophy and the accumulation of lysosome derived fluorescent storage bodies in neurons and most other cells. Common clinical signs include blindness, ataxia, dementia, seizures and premature death. The associated genes for six different human forms have been identified (CLN1, CLN2, CLN3, CLN5, CLN6 and CLN8), and three other human forms suggested (CLNs 4, 7 and 9). A form of NCL in Australian Devon cattle is caused by a single base duplication (c.662dupG) in bovine CLN5. This mutation causes a frame-shift and premature termination (p.Arg221GlyfsX6) which is predicted to result in a severely truncated protein, analogous to disease causing mutations in human Finnish late infantile variant NCL (CLN5), and a simple genetic diagnostic test has been developed. The symptoms and disease course in cattle also matches CLN5. Only one initiation site was found in the bovine gene, equivalent to the third of four possible initiation sites in the human gene. As cattle are anatomically and physiologically similar to humans with a human-like central nervous system and easy to maintain and breed, they provide a valuable alternative model for CLN5 studies. Show less