Human hereditary deafness at the DFNB29 autosomal locus on chromosome 21q22.1 is caused by recessive mutations of CLDN14, encoding claudin 14. This tight junction protein is tetra-membrane spanning that localizes to the apical tight junctions of organ of Corti hair cells and in many other tissues. Typically, the DFNB29 phenotype is characterized by pre-lingual, bi-lateral, sensorineural hearing loss. The goal of this study was to define the identity and frequency of CLDN14 mutations and associated inner ear phenotypes in a cohort of 800 Pakistani families segregating deafness. Hearing loss in 15 multi-generational families was found to co-segregate with CLDN14-linked STR markers. The sequence of the six exons and regions flanking the introns of CLDN14 in these 15 families revealed five likely pathogenic alleles. Two are novel missense substitutions (p.Ser87Ile and p.Ala94Val) while p.Arg81His, p.Val85Asp and p.Met133ArgfsX23 have been reported previously. Haplotype analyses indicate that p.Val85Asp and p.Met133ArgfsX23 are founder mutations. The p.Val85Asp accounts for approximately 67% of the mutant alleles of CLDN14 in our cohort. Combined with previously reported data, CLDN14 mutations were identified in 18 of 800 Pakistani families (2.25%; 95% CI, 1.4-3.5%). Hearing loss in the affected individuals homozygous for CLDN14 mutations varied from moderate to profound. This phenotypic variability may be due to environmental factors (e.g. drug and noise exposure) and/or genetic modifiers.

We ascertained two large Pakistani consanguineous families (PKDF231 and PKDF608) segregating profound hearing loss, vestibular dysfunction, and retinitis pigmentosa, the defining features of Usher syndrome type 1 (USH1). To date seven USH1 loci have been reported. Here, we map a novel locus, USH1K, on chromosome 10p11.21-q21.1. In family PKDF231 we performed a genome-wide linkage screen and found a region of homozygosity shared among the affected individual at chromosome 10p11.21-q21.1. Meiotic recombination events in family PKDF231 define a critical interval of 11.74 cM (20.20 Mb) bounded by markers D10S1780 (63.83 cM) and D10S546 (75.57 cM). Affected individuals of family PKDF608 were also homozygous for chromosome 10p11-21-q21.1 linked STR markers. Of the 85 genes within the linkage interval, PCDH15, GJD4, FZD4, RET, and LRRC18 were sequenced in both families, but no potential pathogenic mutation was identified. The USH1K locus overlaps the non-syndromic deafness locus DFNB33 raising the possibility that the two disorders may be caused by allelic mutations.

Stem cells are extensively used for regenerative purposes as they are unspecialized cells capable of renewal and differentiation. Growth factors like vascular endothelial growth factor (VEGF) play a crucial role in enhancing the regenerative potential of stem cells. The present study was designed to elucidate the effects of VEGF preconditioning in accelerating the regenerative potential of adipose-derived stem cells (ADSCs) for wound healing. In vivo study was carried out using female Sprague Dawley (SD) rats randomly divided into three groups, i.e., VEGF preconditioned ADSCs transplanted group (Pre-Tx), normal ADSCs transplanted group (N-Tx) and control group. ADCS were isolated from female SD rats and treated with VEGF for the Pre-Tx group. At 21st day post-transplantation, the wound in the Pre-Tx group was completely closed. However, the wound was not fully healed in the N-Tx group and the Control group. For further analysis, the experimental area of skin tissues was taken from all groups and examined histologically. The cellularity and granulation were thicker in the pre-Tx group and thicker in the pre-Tx group and thicker, indicating rapid wound recovery. Furthermore, the polymerase chain reaction results also confirmed the down-regulation of apoptotic marker caspase3, which indicates less cell death at the injury site and up-regulation of certain growth factors like IGF, sdf1α and some other markers like E cadherin and vimentin. RT-PCR analysis revealed significant up-regulation of all these factors in the pre-Tx group compared to other groups. These results suggest that VEGF pre-conditioning improves the reparative potency of ADSCs by increasing their survival rate and stimulating the secretion of various growth factors having crucial involvement in angiogenesis and recovery of damaged tissue.