Consanguineous marriage is traditionally common throughout Arab countries. This leads to an increased birth prevalence of infants with recessive disorders, congenital malformations, morbidity and mortality. The aim of this study was to evaluate the rate of consanguineous marriage in families with autosomal recessive diseases, and to compare it with the average rate of consanguinity in the Moroccan population. The study was conducted in the Department of Medical Genetics in Rabat on 176 families with autosomal recessive diseases diagnosed and confirmed by clinical, radiological, enzymatic or molecular investigations. The rate of consanguinity was also studied in 852 families who had infants with trisomy 21 confirmed by karyotyping. These families were chosen because: (i) there is no association between trisomy 21 and consanguinity, (ii) these cases are referred from different regions of Morocco and (iii) they concern all social statuses. Among 176 families with autosomal recessive disorders, consanguineous marriages comprised 59.09% of all marriages. The prevalence of consanguinity in Morocco was found to be 15.25% with a mean inbreeding coefficient of 0.0065. The differences in the rates of consanguineous marriages were highly significant when comparing the general population and couples with offspring affected by autosomal recessive conditions. These results place Morocco among the countries in the world with high rates of consanguinity. Autosomal recessive disorders are strongly associated with consanguinity. This study better defines the health risks associated with consanguinity for the development of genetic educational guidelines targeted at the public and the health sector.

Familial Mediterranean fever (FMF) is an autosomal recessive inherited disease caused by mutations in MEFV. This disease is characterized by recurrent episodes of fever accompanied with topical signs of inflammation. Some patients can develop renal amyloidosis. We prospectively investigated MEFV mutations in a cohort of 209 unrelated Arab patients from Maghreb (85 Algerians, 87 Moroccans, and 37 Tunisians) with a clinical suspicion of FMF. FMF is the main cause of periodic fever syndrome in Maghreb. The most frequent MEFV mutations in this cohort were M694V and M694I. These mutations account for different proportions of the MEFV mutations in Algeria (5%, 80%), Morocco (49%, 37%), and Tunisia (50%, 25%) patients. M694I mutation is specific to the Arab population from Maghreb. Other rare mutations were observed: M680L, M680I, A744S, V726A, and E148Q. We estimated the frequency of MEFV mutation carriers among the Arab Maghrebian population at around 1%, which is significantly lower than in non-Ashkenazi Jews, Armenians or Turks.

Familial Mediterranean Fever (FMF, MIM 249100) is an autosomal recessive disease mainly affecting patients of the Mediterranean basin. It is an autoinflammatory periodic disorder characterised by recurrent episodes of fever and abdominal pain, synovitis and pleuritis. FMF is caused by mutations in the Mediterranean Fever (MEFV) gene located on chromosome 16p13.3. Several mutations in the MEFV gene have been characterised in different populations. However, very little is known about mutations in the MEFV gene in patients with Moroccan origin. The aim of this study is to determine the clinical components of FMF and characterise mutations in the MEFV gene in Moroccan patients. The study was carried out on 120 unrelated Moroccan patients referred to the department of medical genetics in Rabat for suspicious FMF over a period of 10 years. Patients were screened for the most common MEFV mutations by direct sequencing of exons 2 and 10. Of the 120 unrelated patients investigated, 56 patients (47%) were carriers of one or two MEFV mutations, and 64 patients (53%) had no detected mutations. Of those with mutations, 24 were homozygous (44%), 13 were compound heterozygotes (24%), and 19 patients had only 1 identifiable mutation (32%). The most frequent mutation in Moroccan patients is M694V (47%), followed by M694I (32%), A744S (6.5%), M680L (4%), M694del (2%) and E148Q (6.5%). The R761H, K695R and I692del mutations were rarely encountered (less than 1%). The V726A mutation was not found in our study. Our data represent the first report of MEFV gene mutations causing FMF in Moroccans patients. The M694V and M694I mutations are the most common mutations found in MEFV gene in Moroccan population; while the most common mutation in Arabs from the Middle-East region, the V726A, was not found in our population.

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