Genetic Link for Cleft Palate May Help Explain Spinal Defect
Mar. 05, 1987
NEW YORK (AP) _ A newfound link between a faulty gene and a rare form of cleft palate may help lead to better understanding of another birth defect, spina bifida, a scientist says.
Researchers reported today that cases of cleft palate in a family in Iceland have been traced to a gene on a portion of the ''X'' chromosome.
Once the gene is isolated and studied, scientists should get a clue into just how it produces cleft palate, said study co-author Gudrun Moore.
And since cleft palate and spina bifida both involve failure of particular tissues to fuse in an embryo, there may be some similarities in their causes, she said. Some cases of spina bifida are also linked to the X chromosome, and further study of them may shed light on any similarities, she said.
A chromosome is a tiny strand within bodily cells along which genes lie like pearls on a necklace. The X chromosome is one of two that determine the sex of a person.
Norman Coe, executive director of the Spina Bifida Association of America, agreed it is plausible that research into cleft palate could shed light on what causes spina bifida.
Moore is at the biochemistry department at St. Mary's Hospital Medical School at the University of London. She reported the work in the British journal Nature with colleagues at her school, at the Whitehead Institute for Biomedical Research in Cambridge, Mass., and at National University Hospital in Reykjavik, Iceland.
The work involved a cleft of the secondary palate, which is failure of tissues to form the roof of the mouth. The tissues normally fuse to create that feature during the seventh to ninth weeks of gestation.
The cleft, which appears in about one of every 1,500 infants, interferes with speaking ability and causes dental problems. Treatment includes surgery and sometimes speech therapy.
Scientists trace the defect both to genetic and environmental factors such as nutrition and certain medications. The form Moore studied, linked to the X chromosome, accounts for only about 2 percent of secondary palate clefts, she said.
Spina bifida, which occurs in about 1.5 per 1,000 live births, is failure of the spinal column to close fully. In its most serious form, called anencephaly, the brain fails to develop fully and a newborn dies within days.
In other cases, infants can suffer swelling of the brain, urinary problems, eye troubles and bone conditions such as curvature of the spine, said Coe. Many cannot walk or need braces to walk because of the bone problems, he said.
No cure is known, but surgery can help, he said. Defective genes are part of the cause, but some theories suggest environmental contributions as well, he said.
Moore's research studied genes from 82 members of the Iceland family. Nine of the males and one female had cleft palate and 10 females had a condition called ankyloglossia, in which a band of tissue holds the tongue to the bottom of the mouth. One male had an abnormally shaped palate.