Marfan syndrome in a Triplo-X girl: a new association?

Triple X is a sex chromosomal abnormality that involves the presence of three sex chromosomes resulting in 47, XXX karyotype. Most patients suffering from this syndrome are usually mentally normal or subnormal with no gross malformation. To report an unusual association between Triple X and Marfan disease in a girl. A case of a triple X girl with craniofacial dysmorphy and skeletal anomalies, who did feat Marfan criteria by age, is presented. To the best of our knowledge this association has never been reported. Some clinical features are common between Triplo X and Marfan disease so a careful follow-up is needed and investigations should be performed in these patients because Marfan syndrome may be incomplete in early age

X linked mental retardation

Mental retardation [MR] is a group of heterogeneous clinical conditions. There are more than 900 genetic disorders associated with MR and it affects around 3%of the general population. Many MR conditions described are syndromic, fragile X syndrome being the most common clinical entity among them. Xlinked mental retardation [XLMR] is subdivided in two categories: syndromic XLMR [MRXS] when MR is associated with clinical features and non-syndromic XLMR [MRX] when MR is isolated. The aim of this systematic review of the literature was to join together the results of several studies related to X linked mental retardation and to present various genes implicated in this disease. In this review, focus has been given on genes implicated in mental retardation, the clinical data and on phenotype-genotype correlations. An exhaustive electronic and library research of the recent literature was carried out on the Web sites "Science Direct" and "Interscience Wiley". The key words used were "mental retardation", "X chromosome", "gene", "syndromic mental retardation", "non-syndromic mental retardation". In this review a number of X linked genes, the clinical features associated with the gene abnormality, and the prevalence of the disease gene are discussed. We classified these genes by order of their first implication in MR. A table presented on the XLMR Update Web site who list the 82 known XLMR genes is available as XLMR Genes and corresponding proteins

[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

[Interest of studying subtelomeric abnormalities by in situ fluorescent hybridization to explore idiopathic mental retardation]

Nowadays, the genetic basis of mental retardation is a huge field of investigations. Genetic abnormalities frequently give rise to a mental retardation phenotype and are observed in 10 to 40% of known etiologies. New syndromes have identified [chromosome 1p, 22q, 3q29 and 9q34] but for 60% of patients there is no etiology because there is no characteristic phenotype. Many studies involve subtelomeric duplications and deletions in idiopathic mental retardation. The auteurs describe and discuss the interest and the limits of telomeric FISH [Chromoprobe Multiprobe T System] in exploring mental retardation

[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

[Molecular analysis of the smni and naip genes in 60 Tunisian spinal muscular atrophy patients]

In this study we examined the deletion of SMN and NAIP genes in 60 Tunisian families There were 35 patients with type I SMA. 18 with type II SMA, 6 with type Ill SMA and 1 with type IV SMA .The age of onset was before 6 months for type I, between 6 months and 2 years for type II. between 2 years and 17 years for type III and 30 years for type IV. Exon 7 of SMN 1 gene was homozygously deleted in 95% [57/60] of SMA patients. There was a higher frequency of homozygous absence of SMN I in type I and type 11 [100% and 94% respectively] than in type III [66,7%]. SMN 1 exon 8 was undetectable in 88%[53/60] of patients .The case type II patient with homozygous deletion of SMN I exon 7 and not exon 8 was tested for the presence of a hybrid SMN gene. This patient showed in the second PCR a SMN I exon 8 product by restriction site assay indicating that a gene conversion event had occurred. All parents' individuals retained one copy of their SMN I gene. Exon 5 of NAIP gene was homozygously deleted in 58% [35/60] of patients [77% in type I [27/35], 27, 7% in type 11 [5/18], 50% [3/6] in type III [Table 1]. No patient had a deletion in NAIP gene without a deletion in the SMN1 gene. Homozygous deletion of NAIP exon 5 was detected in 1 parent. Our results show that the incidence of NAIP deletion is higher in the more severe SMA cases

de'terminisme du sexe

Sex determinism is the series of mechanisms that make an undifferentiated gonad start the process that will lead to testicular or ovarian development. It consists of a very complex cascade sequence that necessitates the interaction of several genes. We review in this work this cascade sequence with in particular the SRY gene which the primary signal that will trigger the formation of the testis. The role of several other genes in sex determination has been also demonstrated and is reviewed such as DSS, WTI, SFI, SOX9,. although their made and sequence of the action in the cascade are still being investgated