What does the GJB2 gene do?
Normal Function. The GJB2 gene provides instructions for making a protein called gap junction beta 2, more commonly known as connexin 26. Connexin 26 is a member of the connexin protein family.
What is connexin gene?
Background: Connexins are a family of transmembrane proteins that are widely expressed in the human body. Connexins play an important role in cell-cell communication and homeostasis in various tissues by forming gap junction channels, which enable a direct passage of ions or metabolites from one cell to another.
How common is GJB2 mutation?
We found 19 previously reported pathogenic variants, and 5 variants found in this study were unclassified, so the carrier frequency of the GJB2 mutations is estimated to be at least 3.73–4.72% (19–24/509).
What is the function of connexin?
Connexins constitute a large family of trans-membrane proteins that allow intercellular communication and the transfer of ions and small signaling molecules between cells.
Where is connexin found?
Connexins have been found in the nucleus, where they may function as transcription factors, and at the mitochondrial membrane, where they may function in bcl-2 activation and apoptosis.
How do we know if deafness will be passed down?
A recessive gene mutation that causes deafness in a child must have been passed on by both the mother and father. If the child only inherits one copy of the affected gene from one parent, they’ll be a carrier. This means that although they can hear, they can pass on the affected gene to their own children.
What is connexin 26 deafness?
Hearing loss due to mutations in the connexin gene family, which encodes gap junctional proteins, is a common form of hereditary deafness. In particular, connexin 26 (Cx26, GJB2) mutations are responsible for ~50% of non-syndromic hearing loss, which is the highest incidence of genetic disease.
Is GJB2 hearing loss progressive?
Conclusions. Hearing loss owing to GJB2 mutations ranges from mild to profound and is usually congenital. More than 50% of patients will experience some hearing loss progression, generally gradually but occasionally precipitously.
Will deaf parents have a deaf child?
There is a wide variation in the causes of deafness. Because of this 9 out of 10 deaf children are born to hearing parents and 1 out of 10 children born to deaf parents are also deaf. With current tests, it is only possible to determine the probable cause of their deafness for about half (40-50%) of children.