Evolution of molecular diagnosis of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is the commonest of the muscular dystrophies. The DMD gene (DMD) is the biggest human gene and the most common molecular defect in the DMD gene, accounting for approximately 65 % of cases of DMD, is the deletion of one or more exons. The most basic method still in regular use involves multiplex PCR of the exons, known to be most commonly deleted. The multiplex is relatively simple. Quantitative analysis of all exons of the gene and multiplex ligation-dependent probe amplification have brought about an improvement in mutation detection rate, as they will detect all exon scale deletions as well as duplications, widely used to detect exonic and intronic mutations. As a sensitive and discriminative tool, MLPA can be used for prenatal testing. A more recent development in quantitative analysis is the use of oligonucleotide-based array comparative genomic hybridization.

Prevalence of angiotensin-converting enzyme, methylenetetrahydrofolate reductase, Factor V Leiden, prothrombin and apolipoprotein E gene polymorphisms in Morocco.

BACKGROUND: Evidence of the influence of genetic risk factors on cardiovascular diseases is more or less established. These genetic factors are involved in several pathways affecting blood pressure regulation, blood coagulation, homocysteine and lipid metabolisms. AIM: We evaluated frequencies of five genetic polymorphisms to assess their informativeness as markers for prospective clinical studies. SUBJECTS AND METHODS: 182 healthy Moroccan subjects were genotyped for ACE I/D by amplification alone and by amplification followed by enzymatic digestion for other polymorphisms. RESULTS: Allele frequencies of ACE ID, MTHFR C677T were 76.6%, 26.9% for D and T alleles, respectively. APOE polymorphism showed 11.3%, 78.6% and 10.2% for the alleles E2, E3 and E4, respectively. The frequency for FII G20210A polymorphism was around 2.7% for A allele. Our data showed an absence of FVL mutation. Using allele frequencies, genetic distances between Moroccan and other populations revealed an independent variability of these polymorphisms. CONCLUSION: These values appear to be influenced by findings in European and African peoples, and may be considered in assessing the clinical significance of a predisposition to cardiovascular disease.

A rapid polymerase chain reaction-based test for screening Steinert's disease (DM1).

Myotonic dystrophy (DM) is a multisystemic neuromuscular disorder caused by a dynamic mutation of (CTG) trinucleotide repeats in the 3' untranslated region of the myotonic dystrophy protein kinase gene (DMPK). The aim of the present study was to establish the use of polymerase chain reaction (PCR)-based simple and rapid method for initial sample screening. Only a minority of samples were tested positive with the above method and need to be detected by tri primer (TP)-PCR and Southern blotting which is more time consuming and involves use of radioactive material. This study concerned 24 patients from nine families with a clinical diagnosis of the DM1. DNA extracted from the blood was used for amplification of the triplet repeat sequences at the DMPK loci. We obtained two bands for the normal subjects and one band for patients corresponding to normal DMPK allele, confirmed by the TP-PCR and the Southern blot. This rapid test for initial screening of samples for the presence of DMPK mutations is economical and reliable method. This method reduces the number of samples needing TP-PCR and Southern blotting.

Duchenne and Becker muscular dystrophy: contribution of a molecular and immunohistochemical analysis in diagnosis in Morocco.

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are X-linked recessive disorders caused by mutations of the DMD gene located at Xp21. In DMD patients, dystrophin is virtually absent; whereas BMD patients have 10% to 40% of the normal amount. Deletions in the dystrophin gene represent 65% of mutations in DMD/BMD patients. To explain the contribution of immunohistochemical and genetic analysis in the diagnosis of these dystrophies, we present 10 cases of DMD/BMD with particular features. We have analyzed the patients with immunohistochemical staining and PCR multiplex to screen for exons deletions. Determination of the quantity and distribution of dystrophin by immunohistochemical staining can confirm the presence of dystrophinopathy and allows differentiation between DMD and BMD, but dystrophin staining is not always conclusive in BMD. Therefore, only identification involved mutation by genetic analysis can establish a correct diagnosis.

The Aurora Kinase C c.144delC mutation causes meiosis I arrest in men and is frequent in the North African population.

Infertility concerns a minimum of 70 million couples worldwide. An important proportion of cases is believed to have a genetic component, yet few causal genes have been identified so far. In a previous study, we demonstrated that a homozygous mutation (c.144delC) in the Aurora Kinase C (AURKC) gene led to the production of large-headed polyploid multi-flagellar spermatozoa, a primary infertility phenotype mainly observed in North Africans. We now want to estimate the prevalence of the defect, to improve our understanding of AURKC physiopathology in spermatogenesis and assess its implication in oogenesis. A carrier frequency of 1/50 was established from individuals from the Maghrebian general population, comparable to that of Y-microdeletions, thus far the only known recurrent genetic event altering spermatogenesis. A total of 62 patients were genotyped, all who had a typical phenotype with close to 100% large-headed spermatozoa were homozygously mutated (n = 32), whereas no AURKC mutations were detected in the others. Two homozygous females were identified; both were fertile indicating that AURKC is not indispensible in oogenesis. Previous FISH results had showed a great chromosomal heterogeneity in these patient's spermatozoa. We demonstrate here by flow cytometry that all spermatozoa have in fact a homogeneous 4C DNA content and are thus all blocked before the first meiotic division. Our data thus indicate that a functional AURKC protein is necessary for male meiotic cytokinesis while its absence does not impair oogenesis.