Recessive splice site and nonsense mutations of PCDH15, encoding protocadherin 15, are known to cause deafness and retinitis pigmentosa in Usher syndrome type 1F (USH1F). Here we report that non-syndromic recessive hearing loss (DFNB23) is caused by missense mutations of PCDH15. This suggests a genotype-phenotype correlation in which hypomorphic alleles cause non-syndromic hearing loss, while m...

The study comprised 25 patients with Syndromic genetic hearing loss. They were selected from the Audiology Unit, Faculty of Medicine, and the Human Genetics clinic, Medical Research Institute, , Alexandria University. Their ages ranged from 2.5 to 19 years. Males were more affected than females (M/F ratio = 2:1). T he high parental consanguinity (63.2 %) emphasizes the contribution of autosomal...

Autosomal-recessive genes account for about 80% of the patients of non-syndromic deafness, and a major portion of those lead to cochlear pathology. Given the strong cultural practice of consanguineous marriages and the lack of awareness regarding screening modalities, a high prevalence of hereditary pre-lingual deafness is seen in Pakistan. Considering the situation, cochlear implant surgery wa...

Advances in sequencing technologies and increased understanding of the contribution of genetics to congenital sensorineural hearing loss have led to vastly improved outcomes for patients and their families. Next-generation sequencing and diagnostic panels have become increasingly reliable and less expensive for clinical use. Despite these developments, the diagnosis of genetic sensorineural hea...

Human pendrin (SCL26A4, PDS) is a 780 amino acid integral membrane protein with transport function. It acts as an electroneutral, sodium-independent anion exchanger for a wide range of anions, such as iodide, chloride, formate, bicarbonate, hydroxide and thiocyanate. Pendrin expression was originally described in the thyroid gland, kidney and inner ear. Accordingly, pendrin mutations with reduc...

BACKGROUND Non-syndromic hearing loss is among the most genetically heterogeneous traits known in humans. To date, at least 50 loci for autosomal dominant non-syndromic sensorineural hearing loss (ADNSSHL) have been identified by linkage analysis. OBJECTIVE To report the mapping of a novel autosomal dominant deafness locus on the long arm of chromosome 14 at 14q11.2-q12, DFNA53, in a large mu...

Hearing loss is the most common inherited sensorial deficiency in humans; about 1 in 1000 children suffer from severe or profound hearing loss at birth. Mutations in the GJB2 gene are the most common cause of prelingual, non-syndromic autosomal recessive deafness in many populations; the c.35delG mutation is the most common in Caucasian populations. The frequency of the c.35delG mutation was es...

The pathogenetic mechanism of the human mitochondrial 12S rRNA gene mutation at position 1555, associated with non-syndromic deafness and aminoglycoside-induced deafness, has been investigated in 33 transformants obtained by transferring mitochondria from lymphoblastoid cell lines into human mitochondrial DNA (mtDNA)-less (rho *206) cells. In this nearly constant nuclear background, 15 transfor...

We have cloned a human cDNA, DELGEF (deafness locus associated putative guanine nucleotide exchange factor), derived from a 225 kb genomic sequence of chromosome 11p14, critical for the Usher 1C syndrome and for DFNB18, a locus for non-syndromic sensorineural deafness. The amino acid sequence of the protein hDelGEF1 is homologous to the nucleotide exchange factor RCCI for the small GTPase Ran. ...