Genetic linkage analysis of 15 DFNB loci in a group of Iranian families with autosomal recessive hearing loss

Hearing loss [HL] is the most frequent sensory birth defect in humans. Autosomal recessive non-syndromic HL [ARNSHL] is the most common type of hereditary HL. It is extremely heterogeneous and over 70 loci [known as DFNB] have been identified. This study was launched to determine the relative contribution of more frequent loci in a cohort of ARNSHL families. Thirty-seven Iranian families including 36 ARNSHL families and 1 family with Pendred syndrome each with >/= 4 affected individuals, from seven provinces of Iran, were ascertained. DFNB1 contribution was initially studied by DNA sequencing of GJB2 and linkage analysis using the relative STR markers. The excluded families were then subjected to homozygosity mapping for fifteen ARNSHL loci. Sixteen families were found to be linked to seven different known loci, including DFNB1 [6 families], DFNB4 [3 families +1 family with Pendred syndrome], DFNB63 [2 families], DFNB2 [1 family], DFNB7/11 [1 family], DFNB9 [1 family] and DFNB21 [1 family]. DNA sequencing of the corresponding genes is in progress to identify the pathogenic mutations. The genetic causes were clarified in 43.2% of the studied families, giving an overview of the causes of ARNSHL in Iran. DFNB4 is ranked second after DFNB1 in the studied cohort. More genetic and epigenetic investigations will have to be done to reveal the causes in the remaining families

Making an experimental animal model for multiple sclerosis

To understand the mechanism of Multiple Sclerosis [MS], an autoimmune demyelinating disease, the researchers developed an experimental animal model for MS, which is called EAE [Experimental Allergic Encephalomyelitis]. There are several methods for inducing this animal model. In this research the active EAE, which is developed by injecting bovine myelin antigens into genetically susceptible animals, was used. Proteolipid protein [PLP], which is a prominent neuroantigen, was extracted from fresh bovine brain, and used for inducing EAE in female Balb/C and Guinea pig. Animals were weighed and examined daily for clinical symptoms. Also histological sections from EAE brains were prepared. These sections showed infiltration, congestion and demyelination