KCNQ4 Gene

Definition: Potassium voltage-gated channel, KQT-like subfamily, member 4

Official Symbol:KCNQ4

 Chromosome:1

 Location : 1p34

Gene Size: 54677 bp (41022271..41076947)


No Exons:14


Description:

The protein encoded by this gene forms a potassium channel that is thought to play a critical role in the regulation of neuronal excitability, particularly in sensory cells of the cochlea. The current generated by this channel is inhibited by M1 muscarinic acetylcholine receptors and activated by retigabine, a novel anti-convulsant drug. The encoded protein can form a homomultimeric potassium channel or possibly a heteromultimeric channel in association with the protein encoded by the KCNQ3 gene,Potassium channels made with the KCNQ4 protein are found in the inner ear and along part of the nerve pathway from the ear to the brain (auditory pathway). KCNQ4 potassium channels are also found in small numbers in the heart and some muscles.

Disease :

Defects in this gene are a cause of nonsyndromic sensorineural deafness type 2 (DFNA2), an autosomal dominant form of progressive hearing loss. Two transcript variants encoding different isoforms have been found for this gene.

Nonsyndromic deafness - caused by mutations in the KCNQ4 gene

    Several KCNQ4 mutations have been reported in individuals with a form of nonsyndromic deafness (hearing loss without related signs and symptoms affecting other parts of the body) called DFNA2. Most KCNQ4 mutations change one of the building blocks (amino acids) used to make the KCNQ4 protein. Nearly all of these changes affect the region of the protein that forms the pore or channel opening. As a result, the channel does not function properly and normal potassium ion levels may be disturbed. Two mutations delete part of the KCNQ4 gene, which results in an abnormally small KCNQ4 protein that cannot form functional channels. It is unclear whether deafness results from disturbed potassium levels within the inner ear, alterations in the auditory pathway, or both.

ESPN Gene

Definition:

The official name of ESPN is "espin",ESPN is the official Gene symbol,it is also knwon has DFNB36; LP2654; DKFZp434A196; DKFZp434G2126

Chromosome:1

Position:1p36.31; 1p36.31-p36.11

Gene Size: 36157 bp (6407435 to 6443591


No of  Exons: 13

Description:

ESPN  provides instruction for making a protein called espin.This protein is active ear where it plays important role in normal hearing and balance,it is believed to bind  with actin a protein that is important for cell movement and shape,it probably involved in the growth and maintiance of hair like projections called strereocilia,Espin may also play a role in other types of sensory cells. Some studies suggest that this protein is present in taste receptor cells, cells involved in recognizing smells, and Merkel cells in the skin, which are associated with the sense of touch. In these cells, espin is located in small, fingerlike structures called microvilli that project from the cell surface. Like stereocilia in the inner ear, microvilli contain a large amount of actin.

Disease :

Mutations in ESPN gene causes nonsyndromic deafness(hearing loss without related signs and symptoms affecting other parts of the body) called DFNB36.Several  mutations in ESPN gene  cause an autosomal recessive form of nonsyndromic deafness that includes problems with balance. Autosomal recessive inheritance means that two copies of the gene in each cell are altered. These genetic changes delete a small amount of DNA from critical regions of the ESPN gene. Researchers believe that these genetic changes may prevent the production of espin or lead to an abnormally small, nonfunctional version of the protein that cannot bind to actin. A loss of espin function likely disrupts the development, structure, and organization of stereocilia, leading to hearing loss and balance problems.