[Confirmation of the high prevalence in Morocco of the homozygous mutation c.144delC in the aurora kinase C gene (AURKC) in the teratozoospermia with large-headed spermatozoa]. / Confirmation de la forte prévalence au Maroc de la mutation homozygote c.144delC du gène aurora kinase C (AURKC) dans les tératozoospermies avec spermatozoïdes macrocéphales.

OBJECTIVES: To confirm the recurrent character of the mutation c.144delC in the aurora kinase C (AURKC) gene in Morocco and determine the indication and the interest of the research of this anomaly. PATIENTS AND METHODS: We looked for the mutation c.144delC in the AURKC gene in 18 infertile Moroccan patients. They were seen in medical genetic consultation within the framework of the preparatory assessment for medically-assisted procreation. Genomic DNA was extracted from 5 ml of EDTA-blood. The gene AURKC exon 3 was amplified by PCR then sequenced by using the Big-Dye Terminator V3.1 kit and an ABI Prism 310 Genetic Analyzer (Applied Biosystems). RESULTS: All the patients who had a typical phenotype with high rates of large-headed spermatozoa were homozygous for the mutation c.144delC in the AURKC gene. CONCLUSION: We confirm in this study the research interest of the recurrent mutation c.144delC in the gene AURKC in male infertility with high rates of large-headed spermatozoa. This molecular analysis avoids to many infertile couples unnecessary expenses and succession failures in case of use of medically-assisted procreation (MAP).

Autosomal dominant anhidrotic ectodermal dysplasias at the EDARADD locus.

Anhidrotic ectodermal dysplasia (EDA) is a disorder of ectodermal differentiation characterized by sparse hair, abnormal or missing teeth, and inability to sweat. X-linked EDA is the most common form, caused by mutations in the EDA gene, which encodes ectodysplasin, a member of the tumor necrosis factor (TNF) family. Autosomal dominant and recessive forms of EDA have been also described and are accounted for by two genes. Mutations in EDAR, encoding a TNF receptor (EDAR) cause both dominant and recessive forms. In addition, mutations in a recently identified gene, EDARADD, encoding EDAR-associated death domain (EDARADD) have been shown to cause autosomal recessive EDA. Here, we report a large Moroccan family with an autosomal dominant EDA. We mapped the disease gene to chromosome 1q42.2-q43, and identified a novel missense mutation in the EDARADD gene (c.335T>G, p.Leu112Arg). Thus, the EDARADD gene accounts for both recessive and dominant EDA. EDAR is activated by its ligand, ectodysplasin, and uses EDARADD to build an intracellular complex and activate nuclear factor kappa B (NF-kB). We compared the functional consequences of the dominant (p.Leu112Arg) and recessive mutation (p.Glu142Lys), which both occurred in the death domain (DD) of EDARADD. We demonstrated that the p.Leu112Arg mutation completely abrogated NF-kB activation, whereas the p.Glu142Lys retained the ability to significantly activate the NF-kB pathway. The p.Leu112Arg mutation is probably a dominant negative form as its cotransfection impaired the wild-type EDARADD's ability to activate NF-kB. Our results confirm that NF-kB activation is impaired in EDA and support the role of EDARADD DD as a downstream effector of EDAR signaling.

Linkage analysis of families with severe childhood autosomal recessive muscular dystrophy in Morocco indicates genetic homogeneity of the disease in north Africa.

It has been previously shown in Tunisian and Algerian families that the locus for SCARMD maps to the proximal part of 13q, and in Algerian families that the disease is associated with deficiency of the 50 kDa dystrophin associated glycoprotein (50DAG). We have tested this linkage in six families from Morocco where this disease is also prevalent. In one family the 50DAG was tested and found to be negative in a muscle biopsy. Our results showed similar linkage in this country, with statistical tests indicating genetic homogeneity between the three Maghreb countries.

Genetic heterogeneity of severe childhood autosomal recessive muscular dystrophy with adhalin (50 kDa dystrophin-associated glycoprotein) deficiency.

Severe autosomal recessive muscular dystrophy (SCARMD), McKusick n. 253700, has been originally described in North-African populations, in which significant linkage has been established with DNA markers mapping to the proximal region of the long arm of chromosome 13, without evidence for heterogeneity of the SCARMD locus in these populations. A striking feature of this disease is the isolated deficiency of adhalin, a sarcolemmal 50 kDa dystrophin-associated glycoprotein. We report a non-inbred French family with a milder progressive form of muscular dystrophy affecting subjects of both sexes. The parents are not affected suggesting an autosomal recessive transmission. In 4 siblings displaying mild to overt clinical signs of muscular dystrophy, serum creatine kinase was high, and muscle specimens showed variable degree of necrosis-regeneration with little fibrosis. In the 4 cases adhalin was completely absent in muscle sections, whereas dystrophin and the other members of the dystrophin-associated protein complex were normal, except for the 35 kDa dystrophin-associated glycoprotein which was decreased as usually observed in SCARMD. Linkage and homogeneity analysis using 4 microsatellite markers of chromosome 13q that are linked to the North-African SCARMD locus were performed in this family. Results show that the morbid locus involved in this family does not map to the same region as the SCARMD locus. This second locus may be involved in sporadic cases of muscular dystrophy with adhalin deficiency that have been reported in Europe.