Genetic Cause Of Two Types Of Cleft Lip: The Twin Approach

Cleft lips and palates can be caused by either genetic or environmental factors. Jeff Murray (of The University of Iowa) and colleagues collected a large number of families with children affected by one of two cleft lip disorders -- Van der Woude and popliteal pterygium syndromes. Previous studies had indicated that the relevant gene or genes sit in a region of chromosome 1, but collaring the ‘causative’ gene was difficult, because of the many genes and SNPs in the region. To get around this problem, the researchers focused their attention on a pair of identical twins--one has a cleft lip, and the other does not. As the twins are (almost) genetically identical, the scientists reasoned that comparison of their DNA would divulge only one difference: the mutation causing the condition. This approach led them to identify a mutation in the gene encoding interferon regulatory factor 6, which produces a protein involved in turning other genes on and off.

Analysis of 57 other families found mutations associated with both cleft disorders. Murray and colleagues have not only identified a gene that controls the development of the face of the embryo—they have demonstrated for the first time that you can track down a ‘disease’ gene by analyzing a pair of ‘identical’ twins.

Author contact details:
Dr. Jeff Murray
University of Iowa
Iowa City, IA, USA
Tel: + 1 319 335 6897
E-mail: jeff-murray@uiowa.edu

(C) Nature Genetics press release.

Message posted by: Trevor M. D'Souza