Complete FXN deletion in a patient with Friedreich's ataxia.

Most patients (98%) with Friedreich's ataxia (FRDA) are homozygous for the GAA repeat expansion in FXN. Only a few compound heterozygous patients with an expanded repeat on one allele and a point mutation or an intragenic FXN deletion on the other allele are described. In a minority of the patients only a heterozygous pattern of the repeat expansion can be detected.

Univerricht-Lundborg disease: underdiagnosed in the Netherlands.

Purpose: Univerricht-Lundborg disease (ULD), with its major symptom of action myoclonus, is supposed to be very rare in the Netherlands and western Europe. We hypothesized that the syndrome may be underdiagnosed in patients with myoclonus epilepsy.

Methods: Mutation analysis of the cystatin B gene was performed in 21 cases with uncontrolled myoclonus.

The 2373insG mutation in the MYBPC3 gene is a founder mutation, which accounts for nearly one-fourth of the HCM cases in the Netherlands.

Aims: Hypertrophic cardiomyopathy (HCM) is caused by mutations in genes that encode sarcomeric proteins. In this study we investigated the involvement of the sarcomeric myosin binding protein C in the Dutch HCM population.

Methods And Results: We initially screened 22 Dutch index patients for mutations in the MYBPC3 gene, which revealed four different mutations in 14 patients.

[From gene to disease; progressive myoclonus epilepsy of Unverricht-Lundborg and mutations in the cystatin B gene].

Progressive myoclonus epilepsy type 1 of Unverricht-Lundborg (EPM1) is a rare disorder, associated with mutations in the cystatin B (CSTB) gene. The most prevalent molecular abnormality is an expansion of a dodecamer repeat in the promoter region of the CSTB gene, but point mutations in the CSTB gene have also been found. DNA examination may be useful in discriminating EPM1 from juvenile myoclonic epilepsy, and from other types of progressive myoclonus epilepsy.