[Molecular diagnosis of fragile X syndrome]

The fragile X syndrome was the most frequent etiology of hereditary mental retardation but the clinical diagnosis is not easy and the indivivual clinical symptoms were not specific so the confirmation will be made par molecular study of the gene of the fragile X syndrome. of our study is to realise the molecular diagnosis of the fragile X syndrome in 200 Tunisian boys with mental retardation. Shows that the frequency of the fragile X syndrome is 7.6%. In the most cases there is a family history of mental retardation with midium age at 11 years. All the boys with the full mutation have mental retardation, dysmorphic features and macro-orchidism [pubescent boy]. The screening of the molecular abnormalitie of FMRI gene must be realised in every boy with mental retardation or boy with delayed speach without any identified etliology. The earlier diagosis is important-for genetic counselling

[Treacher collins syndrome: clinical and genetic aspects about 4 cases]

Treacher Collins syndrome was first mentioned by Thompson in 1847, and described by Treacher Collins in 1900, then it was called mandibulo-facial dysostosis and well defined by Franceschetti in 1949. It is a very rare affection occurring 1 in 50.000 live births, which includes facial and auricular anomalies leading to functional, morphological and psychological difficulties due to related handicaps. Treacher Collins syndrome is inherited as autosomal dominant pattern with a variable expressivity and incomplete penetrance of "TCOF1" gene localized at incomplete penetrance of "TCOF1" gene localized at 5q31.3q32. Today the gene is well identified and several mutations have been reported. In this paper we report the case of 4 Tunisian unrelated girls with Treacher Collins syndrome. One of them was born from an affected father. Clinical diagnostic was performed between age 12 days and 2 years demonstrating the large dysmorphic expression. Main clinical features were present in all reported cases. Family at risk might have genetic counselling and probably prenatal diagnostic in some situations. Out of our observations, we gave genetic counselling and proposed ultrasound prenatal diagnosis for two families without molecular study