The genetic causes of some forms of cleft lip and palate are described in two reports in the October issue of Nature Genetics.
In the first report, researchers followed Icelandic, Brazilian, Canadian and American Indian families for 14 years and conducted extensive genetic analyses on data collected from them. Researchers found three genes not previously connected with human disease and compared them with gene sequences from family pedigrees.
They identified mutations in the gene TBX22 that cause a cleft palate defect inherited through the X chromosome, as well as an associated disorder called tongue-tie. The TBX22 gene is important for the proper growth of structures in the face.
In the second report, researchers at the University of Colorado and in Venezuela identified a variant of another gene—PVRL1—that predisposes people from a population in northern Venezuela to a cleft lip and palate defect. They found that 14 of 243 unrelated people who had cleft lip or palate had the genetic mutation, compared with only one of 245 people who did not have cleft lip of palate.
Previously, the scientists had found that mutations in the gene, which is important for cell fusion during development, causes an inherited cleft lip and palate syndrome in another small population in Venezuela. This gene can contribute to both inherited and sporadic forms of the disease.
Together, the two reports provide clues to the causes underlying human developmental defects.
