Improved fluorescent PCR-based assay for sizing CGG repeats at the FRAXA locus.

Fragile X syndrome is the most frequent heritable genetic disease involving mental retardation and is usually caused by an expanded CGG repeat in the first exon of the FMR1 gene. Therefore, searching for CGG expansion at the FRAXA locus among the mentally retarded has become a routine investigation in neuro-paediatric practice. Consequently, we have developed a fluorescent PCR-based assay for sizing repeats as an alternative to laborious and time-consuming Southern blot. The procedure utilises a reverse fluorescent labelled primer, and the Expand Long Template PCR system (Roche) with addition of dimethylsulfoxide and 7-deaza-dGTP It allows precise determination of the CGG repeat number in males and females for alleles from normal to premutation size range and detection of full mutations in males. We believe that this PCR protocol, allowing a high sample throughput, is useful for first-line screening among mentally retarded males, possibly complemented by Southern blot analysis to assess the methylation status of large mutated alleles.

[Course of a case of Gaucher's disease type 1 treated over a year with glucocerebrosidase (Cérédase)]. / Evolution d'une maladie de Gaucher de type 1 traitée pendant un an par la glucocerébrosidase (Cérédase).

Gaucher's disease is caused by a deficiency of glucocerebrosidase. Enzyme replacement therapy with glucocerebrosidase (Ceredase) is available in France since 1991. We report the clinical effectiveness in a woman with type 1 Gaucher's disease treated with the enzyme for one year. Hepatomegaly regressed, bone pain decreased but improvement of severe skeletal manifestations were slow and incomplete.

[Progressive bulbopontine paralysis in children]. / Paralysie bulbopontine progressive de l'enfant.

A case of pons-bulbar palsy in a 10 year-old girl is reported. The authors insist on the fact that motor cranial nerve nuclear dysfunction was isolated, without any pyramidal tract disorder. They also emphasize the slow course of the disease, which after one year of quick progression was stable for the next 5 years. Nineteen identical cases were found in the literature. From this nosographic group, one must exclude patients with associated lateral spinal tract dysfunction: these patients must be discussed with the juvenile or infantile amyotrophic lateral sclerosis group. The heterogeneity of the pons-bulbar paralysis group is also underlined: the course may be quickly fatal or, on the contrary, protracted for a long time; genetic transmission is also quite variable.