To find the gene responsible for Meckel-Gruber and Joubert syndromes, the researchers 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 were used because the embryos are transparent during development.
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 cilia 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. The condition is more common in certain close-knit populations where the gene has been passed down from generation to generation. These include families of Ashkenazi Jewish origin.
"Accurate genetic testing for TMEM216 will be particularly important for families throughout the world that have a history of ciliopathies caused by mutations to this gene," said Professor Attie-Bittach from the University of Paris.
"Now that we have identified a gene that causes Meckel-Gruber syndrome and Joubert syndrome, the role of particular signalling pathways as the embryo is developing can also be more clearly understood," added Professor Colin Johnson from the University of Leeds in the UK.
|Contact: Debra Kain|
University of California - San Diego