2023-06-12 06:00:21
Formerly called “lip lip”, cleft lip and palate (FLP) is the most common craniofacial malformation and affects on average one in 700 to 1,000 live births in Europe, according to sources.
In a article published on May 24 by the scientific journal Nature Communicationsthe Brazilian geneticist Lucas Alvizi Cruz (University of London) suggests that the combination of a genetic factor with an inflammatory environmental factor is responsible for the formation of this malformation of the face which affects the lips and/or the palate (cleft lip, palatal or labiopalatal).
The team focused their research on inherited or ‘familial’ cleft lip and palate, which accounts for around 25% of non-syndromic FLP cases – which are not linked to other abnormalities like in Pierre Robin syndrome.
“We studied six families over several generations. All of their members had a variation on the CDH1 gene, known to be involved in cleft lip and palate, but only a few were born with FLP.”explained Lucas Alvizi Cruz.
The CDH1 gene is responsible for making a protein, E-cadherin, which acts as a kind of glue between neural crest cells. These cells structure the face of the embryo between the seventh and tenth week of pregnancy: “They form the inside of the lips, eyelids, cheekbones, all the bones and muscles of the face…”details the geneticist.
To do this, these architectural cells of the face move like a wave from the back of the skull, on each side of the head, before meeting at the level of the midline. Provided that cadherin E, the “stick” protein, allows them to move in groups and to join correctly on arrival.
A jammed mechanism
It is when a phenomenon stops this mechanism that a cleft lip and palate forms. But the genetic variation of CDH1, called “loss of function”, which leads to a defect in the production of E-cadherin does not lead, on its own, to the formation of an FLP.
Based on knowledge of the causes of this malformation, Lucas Alvizi Cruz and his team formulate hypotheses and experiment with them on mice, Xenopus (amphibians) and human stem cells.
They conclude that an inflammatory environmental factor, such as tobacco, infection or malnutrition, affects the CDH1 gene and also reduces E-cadherin. “When the mutation is combined with a reduction in the protein due to inflammation, the embryo can no longer take it as part of the development of its facial structure”continues Mr. Alvizi Cruz.
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