Clinical study and genetics of non syndromic congenital deafness

Hearing impairment affects 1/1000 infants. Congenital deafness is inherited or apparently sporadic. DFNB1 on chromosome 13 is a major locus for recessive deafness in about 80% of Mediterranean families and the connexin-26 gene gap junction protein b2 [GJB2] is mutated in DFNB1 families. We acquired DNA samples from 38 families of Moroccan children with recessive non-syndromic deafness and 95 unrelated participants with apparently sporadic congenital deafness. Therefore, we analysed the coding region of the GJB2 gene for mutations. Findings: 31.5% of participants with recessive deafness and 21.5% of sporadic deafness had mutations in the GJB2 gene. The 35delG mutation represented 24.1% of GJB2 mutations. GJB2 gene mutation is a major cause of inherited congenital deafness. 35delG mutation is the most common mutation for inherited congenital deafness. This study shows that 35delG mutation prevalence is important in Morocco with a prevalence of 31.5%, while it is inexistent in Asian population, and very rare in Africa [2.2%]. Such prevalence disparity may reflect an anthropological history of human travels. So, 35delG mutation has a Mediterranean origin. In conclusion, the mutation in the connexion-26 GJB2 gene is the most common cause of non syndromic autosomal recessive deafness in Morocco. More studies are needed to confirm these findings

Poliovirus and poliomyelitis vaccines: a review

This paper discusses poliomyelitis, a viral disease with serious sequelae, that remains a health problem in Saudi Arabia. The points discussed are related to aetiology, isolation of the viral agent, laboratory diagnosis, epidemiology and clinical manifestations of poliomyelitis. Special emphasis is placed on the types of poliomyelitis vaccines, their advantages and disadvantages. The purpose of this article is to call attention to this important disease and to stress the need for conducting more studies in order to eradicate this virus from our community