CLN8 Disease Caused by Large Genomic Deletions.

BACKGROUND:The presence of deletions can complicate genetic diagnosis of autosomal recessive disease.METHOD:The DNA of patients was analyzed in a diagnostic setting.RESULTS:We present three unrelated patients each carrying deletions that encompass the 37 kb CLN8 gene and discuss their phenotype. Two of the cases were hemizygous for a mutant allele - their deletions unmasked a mutation in CLN8 on the other chromosome.CONCLUSION:Microarray analysis is recommended in any patient suspected of NCL who is apparently homozygous for a mutation that is not present in one of the parents or when the family has no known consanguinity.