Gene linked to fetal abnormalities identified

A newly identified genetic defect may help reduce fetal abnormalities such as Meckel-Gruber and Joubert syndromes, according to a new study in the journal Nature Genetics.

Researchers have shown that a previously unknown gene, TMEM216, causes Meckel-Gruber and Joubert syndromes, which are known to produce fetal deformities such as abnormal numbers of fingers and toes, along with brain and eye defects.

In order to isolate the gene responsible, DNA samples were examined using both skin cells donated by those with a family history of Meckel-Gruber and Joubert disorders, as well as using in vitro cells.

TMEM216 deformities were found to trigger Meckel-Gruber and Joubert syndromes. Furthermore researchers found that the faulty TMEM216 gene prevented cells from making a protein needed for signalling. The UK Press Association said that without this signalling protein, neural tube development could be affected in maturing embryos, which could lead to brain abnormalities.

Researchers also found Meckel-Gruber and Joubert syndromes were genetic disorders with recessive characteristics. Hence, researchers explained, couples who both have a copy of the mutated TMEM216 gene were found to be at risk of conceiving children with similar birth defects.

Lead researcher Professor Colin Johnson said: 'By understanding the science behind this relatively rare condition, we can gain insight into other developmental conditions that are less serious but far more frequent. Spina bifida, for example, is one of the most common birth defects, affecting one in every 1000 children'.

Meckel-Gryber and Joubert Syndromes are part of a wider family of disorders called 'ciliopathies', where the cell's cilia - finger-like antennae structures - do not function correctly and consequently do not fully respond to cellular signals.