Application of chromosome 16 markers in the differential diagnosis of neuronal ceroid-lipofuscinosis

Genetic heterogeneity of neuronal ceroid lipofuscinosis in The Netherlands

An overview of patients in the Netherlands who are known to us with neuronal ceroid lipofuscinosis (NCL) is presented. Several CLN genes involved in NCL have been isolated or mapped. We have analyzed families with different types of NCL with polymorphic markers linked to CLN loci to investigate the genetic heterogeneity of NCL in the Netherlands. Haplotype analysis suggests that in addition to the CLN2 and CLN6 genes another gene is involved in at least one family with late infantile NCL in the Netherlands. The CLN2 and CLN6 loci have also been excluded in a family with protracted juvenile NCL.

The mitochondrial DNA A3243G mutation in Portugal: clinical and molecular studies in 5 families

Out of 90 Portuguese patients with mitochondrial cytopathy, six harbored the A3243G mutation in the mtDNA tRNA(Leu(UUR)) gene ('MELAS mutation'). They had heterogeneous clinical features, including myopathy with stroke-like episodes, progressive external ophthalmoparesis, diabetes mellitus, and subacute encephalopathy. Histochemical and biochemical analyses of muscle biopsies showed abundant ragged-red fibers reacting positively with the cytochrome oxidase stain, and decreased respiratory chain enzyme activities. On average, the proportion of mutated mtDNA was 67% (20-88%) in tissues from patients and 21% (0-49%) in blood from 20 maternal relatives. The proportion of mutated mitochondrial genomes in muscle did not correlate with clinical presentation or duration of disease. This study, the first in Portuguese patients, confirms the frequent occurrence of the A3243G mutation in patients with mitochondrial diseases, and emphasises the usefulness of genetic testing in reaching a correct diagnosis.

First African-American child with juvenile neuronal ceroid lipofuscinosis

The neuronal ceroid lipofuscinoses are among the most common forms of progressive neurodegenerative disease of childhood. They appear to be panethnic, but there is a special predilection of the infantile subtype in Finland. In the United States, the Batten disease registry of 731 cases shows that juvenile neuronal ceroid lipofuscinosis (JNCL) is the most common form. Here, we report on the first known African-American child with JNCL. Genetic study showed the 1.02-kb deletion typically seen in JNCL cases.