[Williams-Beuren syndrome: a retrospective study of a series of 11 cases at the Mohammed VI University Hospital in Marrakech]. / Syndrome de Williams-Beuren: étude rétrospective d'une série de 11 cas du Centre Hospitalier Universitaire Mohammed VI de Marrakech.

Williams-Beuren syndrome is a rare genetic disease (1/20 000) characterized by a microdeletion at 7q11.23 encompassing about 28 genes, including the elastin gene, ELN. It is a sporadic disease in the majority of cases. Easily identifiable in childhood, this developmental disorder associates suggestive face dysmorphism, cardiac defect, psychomotor retardation and specific behavioural and cognitive profile. We conducted a retrospective study of 11 patients with Williams-Beuren syndrome whose data were collected in the Genetics Department of the Mohammed VI University Hospital of Marrakech. The average age of patients was 6.05 years (SD=6.56; interquartile range=5), with a female predominance (64%; 7/11 patients). Almost all patients were mentally retarded and the diagnosis was confirmed in 100% (11) of patients using fluorescence in situ hybridisation (FISH).

Phenotypic and cytogenetic variability of patau syndrome in Morocco.

The objective of this work was to identify phenotypic features and cytogenetic aspects of trisomy 13 in Moroccan population. The retrospective study was conducted on a group of 9 cases diagnosed cytogenetically with trisomy 13. The study of sex ratio showed a slight female dominance in our group of cases. The major clinical findings included: Holoprosencephaly, microphthalmia and anophthalmia, coloboma of iris, cleft lip and palate, nasal and ear abnormalities, retrognathism and sloping forehead, polydactyly, capillary hemangiomas, omphalocele, congenital heart defect, renal abnormalities, cryptorchidism, language delay. The cytogenetic study showed the dominance of the free and homogeneous trisomy 13 (56%). Patients who have this formula are dead at an early age (does not exceed one month). However, each of the chromosomal formula, trisomy 13 by translocation and partial trisomy 13 t (13;18), was found in 20% of our patients. The partial trisomy 13 t (13;18) is the only variant that is still alive and the patients with this anomaly suffer mainly from renal and cardiac anomalies with slight dysmorphia and psychomotor retardation. Our study shows the interest of the cytogenetic analysis in the diagnosis accuracy and in the genetic counseling of patients with Patau syndrome and their parents.

Spinocerebellar ataxia Type 7: clinical and genetic study of a new Moroccan family (case report).

Spinocerebellar ataxia type 7 (SCA7) is a rare autosomal dominant neurodegenerative disease. Its clinical presentation is a progressive cerebellar ataxia associated with cone and retinal dystrophy. The CAG repeat expansion in the ataxin-7 gene (ATXN7) causes spinocerebellar ataxia type 7 - a mutation that results in the degeneration of the brain stem cells, retina and cerebellum. We report in this study the clinical and genetic features of a new Moroccan family of SCA7, from the South of Morocco. We performed the molecular genetic testing to confirm the diagnosis of SCA7. The objective of this study is to report a new Moroccan case of SCA7 and to illustrate the role of the geneticist in the diagnosis, management and development of genetic counseling of SCA7 disease.

1p36 deletion syndrome: first case report in Morocco detected by fluorescence in situ hybridization.

The 1p36 deletion syndrome results from a heterozygous deletion of the terminal chromosomal band of the short arm of chromosome 1. Monosomy 1p36 is the most common terminal deletion observed in men (1 in 5000 newborns), characterized by distinctive dysmorphia, delayed growth, psychomotor retardation, intellectual deficit, epilepsy and heart defects. Fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH-array) are currently the two best diagnostic techniques. The objective of this work is to take stock of the first Moroccan case of 1p36 deletion and to illustrate the role of the geneticist in the diagnosis and management of this syndrome. There is currently no effective medical treatment for this disease.