Comorbidity in the Tunisian population.

Genetic diseases in the Tunisian population represent a real problem of public health as their spectrum encompasses more than 400 disorders. Their frequency and distribution in the country have been influenced by demographic, economic and social features especially consanguinity. In this article, we report on genetic disease association referred to as comorbidity and discuss factors influencing their expressivity. Seventy-five disease associations have been reported among Tunisian families. This comorbidity could be individual or familial. In 39 comorbid associations, consanguinity was noted. Twenty-one founder and 11 private mutations are the cause of 34 primary diseases and 13 of associated diseases. As the information dealing with this phenomenon is fragmented, we proposed to centralize it in this report in order to draw both clinicians' and researcher's attention on the occurrence of such disease associations in inbred populations as it makes genetic counseling and prenatal diagnosis challenging even when mutations are known.

Biotinidase deficiency: novel mutations in Algerian patients.

Biotinidase deficiency is an autosomal recessive disorder of biotin metabolism leading to varying degrees of neurologic and cutaneous symptoms when untreated. In the present study, we report the clinical features and the molecular investigation of biotinidase deficiency in four unrelated consanguineous Algerian families including five patients with profound biotinidase deficiency and one child characterized as partial biotinidase deficiency. Mutation analysis revealed three novel mutations, c.del631C and c.1557T>G within exon 4 and c.324-325insTA in exon 3. Since newborn screening is not available in Algeria, cascade screening in affected families would be very helpful to identify at risk individuals.

A study survey on intestinal and blood parasites among school children in Sana'a province, Yemen.

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Vitamin B-complex deficiency and visual acuity.

1. A study was carried out on 973 school children to find out any relationship between vitamin B-complex deficiency signs and defective vision, and the effect of supplementation of B-complex vitamins on visual acuity. 2. The results of the study showed a significant association between presence of clinical signs of vitamin B-complex deficiency and defective vision. 3. Supplementation with vitamin B-complex was found to have a beneficial effect in improving the visual-acuity status of defective children and in preventing visual defects from developing. 4. It is concluded, therefore, that from the present study it appears that the relationship between vitamin B-complex deficiency and visual defects could be one of 'cause and effect'.