Cold Spring Harbor, NY By identifying a protein that acts as a genetic modifier, scientists at Cold Spring Harbor Laboratory (CSHL) have solved the mystery of why some infants are born with a grave syndrome consisting of cleft palate and major deformities of the skin and limbs, while other infants bearing the same predisposing genetic mutation bear little or no sign of the illness, called EEC.
EEC stands for "Ectodactyly, Ectodermal dysplasia, Clefting syndrome." It is rare in its full-blown form, although individual aspects of the associated pathology, such as cleft palate, are more common.
EEC has a known genetic culprit, a single-"letter" DNA mutation in a gene called p63. This error causes a mutation in the p63 protein that the gene encodes. EEC is autosomal dominant, meaning that only one parent needs to contribute the defective copy of the gene for a child to develop the illness. When one parent carries the mutant gene, each child has a 50% chance of having EEC.
"But the big question is why some children with the mutation have severe birth defects, while othersin some cases, siblings of those affectedwho bear the same p63 mutation, are mostly or entirely symptom-free," says Professor Alea Mills, Ph.D., the CSHL geneticist who led the team that has just solved this mystery.
A complex series of genetic experiments directed by Mills reveals that the presence or absence of one variant type of the p63 protein, called TAp63, determines whether or not a child with the p63 mutation will in fact develop EEC pathology. TAp63 normally protects from the birth defects, and if it is not present, pathology is certain to occur, the team's experiments showed.
Solving the mystery of variable pathology
In 1999, Mills made the first genetic "knock-out" model for p63, in mice, putting the p63 gene on the map. Mice completely lacking the p63 gene were born with birth defects similar to the severest symptoms th
|Contact: Peter Tarr|
Cold Spring Harbor Laboratory