LONDON: In what could be called a
major breakthrough, scientists claim to have identified a gene which is linked
to birth defects in many individuals.
An international team, led by
Leeds University, has, in fact, found the genetic cause of inherited conditions
-- Meckel-Gruber syndrome and Joubert syndrome -- that causes severe foetal
abnormalities, the 'Nature Genetics' reported.
Meckel-Gruber syndrome
and Joubert syndrome are part of a wider family of disorders known as
"ciliopathies" --so called because the cilia are not working as they should and
don't respond properly to signals.
This lack of communication can
prevent the neural tube from developing correctly in growing embryos, leading to
abnormalities in the brain. Affected embryos can also develop abnormalities in
the eyes, extra fingers or toes, and multiple cysts in their kidneys, say the
scientists.
To find the gene responsible for Meckel-Gruber and
Joubert syndromes, the scientists examined DNA from families with a history of
the disorder, from skin cells donated by patients, and from cells grown in the
laboratory. They also studied zebrafish, which have very visible
embryos.
The work identified a previously unknown gene --TMEM216 --
as a cause of Meckel-Gruber and Joubert syndromes. They also showed that the
faulty TMEM216 gene stopped cells from making a protein that is needed for
signalling.
Because Meckel-Gruber and Joubert syndromes are recessive
genetic disorders, only couples who both have a copy of the disease gene are at
risk of conceiving babies with these birth defects.
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