Northwestern University researchers have discovered a gene, DMP1 (for dentin matrix protein), that may help unravel the mystery of how teeth normally harden. When mutated, the gene appears to be linked to the hereditary disease, Dentinogenesis Imperfecta Type II, a defect affecting 1 in every 10,000 people, where teeth become weak and turn a dull bluish brown.
Molecular biologist Anne George said DMP1 bears biological resemblance to many calcium-attracting molecules of bones, but is the first of its kind to be found in teeth. The two classes of molecules might work by pulling calcium from the bloodstream and depositing the mineral into developing teeth and bones, she said.
The results will be published in the November issue of the Journal of Histochemistry and Cytochemistry.
LASER SAVES TWINS AT RISK IN WOMB
Using a laser to redirect the flow of blood in fetuses still in the womb, Dr. Julian De Lia of the Medical College of Wisconsin in Milwaukee is saving the lives of identical twins who are prone to dangerous blood flow problems.
The condition, known as Twin to Twin Transfusion Syndrome, occurs in about 5 percent of pregnancies involving identical twins or triplets and is fatal 80 to 100 percent of the time.
The condition is caused by abnormalities in the placenta, which cause one twin to receive too much blood and the other not enough. As a result, one fetus usually dies of anemia and the other from an overworked heart.
Inserting a flexible laser scope through a small hole in a pregnant woman’s abdomen, De Lia seals off abnormal blood channels from the placenta, thus enabling all the fetuses to receive equal amounts of blood. So far the new laser surgery has saved one set of triplets, seven sets of twins and nine sole surviving twins.
ENVIRONMENTAL LINKS TO SCHIZOPHRENIA
Schizophrenia has strong genetic links but it is also affected by such environmental factors as exposure to chemicals and viruses, a study of adopted children in Denmark has found.
The study, which involved 8,944 children who were adopted outside Copenhagen from 1924 through 1947, showed that schizophrenia was 10 times more likely in the relatives of schizophrenic patients than in the relatives of normal control group members, said Dr. Seymour S. Kety of the Danish National Institute of Mental Health.
“Continued investigation of the genetic and extragenetic contributions will be necessary to elucidate the modes of genetic transmission and expression, and to identify and define the large number of environmental influences operating in tandem with them in the development of this disorder,” Kety reported in the Archives of General Psychiatry.
