University Of Maryland Researchers Report On Genetics Of Asthma, Adult-Onset Diabetes, Lethal Dwarfism, And Cardiovascular Disease

GENETICS OF ASTHMA

At least two genes control bronchial hyper-responsiveness, a major characteristic of asthma, genetics researchers at the University of Maryland School of Medicine report.

In a study of 123 Dutch families, Eugene Bleecker, MD, and Deborah Meyers, PhD, codirectors of the UM Center for the Genetics of Asthma and Complex Diseases, Jianfeng Xu, MD, DrPh, assistant professor of medicine at the UM medical school, and colleagues at University Hospital Groningen in The Netherlands, found one major locus and another modifier locus.

The two genes account for 74.3 percent of the bronchial hyper-responsiveness in the Dutch families studied.

The Maryland researchers will present a poster on their work on Wednesday, October 29 at the American Society of Human Genetics annual meeting in Baltimore.

AMISH STUDY HELPS IDENTIFY GENES FOR ADULT-ONSET DIABETES

Studies of 950 Amish volunteers from the Lancaster, Pennsylvania, area may help researchers at the University of Maryland School of Medicine identify the regions on chromosomes and specific disease-related genes for adult-onset diabetes.

Alan Shuldiner, MD, head of the Division of Diabetes, Obesity and Nutrition at the Baltimore medical school, has been traveling the Amish countryside for the past five years, taking blood samples to test for diabetes and cholesterol.

DNA from the blood is used to perform more than 400 different genetic tests on each sample. Shuldiner treats study subjects diagnosed with diabetes, providing blood-glucose monitors and instruction on monitoring their blood-glucose levels at home, as well as information on proper diet and exercise. He will report on the research, funded by Glaxo Wellcome Inc. and Sequana Therapeutics Inc., on Thursday, October 30, at the American Society of Human Genetics annual meeting in Baltimore.

MUTATION LINKED TO CARDIOVASCULAR, KIDNEY DISEASE

A genetic mechanism that may play a role in cardiovascular and kidney disease has been identified by University of Maryland School of Medicine genetics researcher Rong-Fong Shen, PhD, and colleagues.

They will present a poster on their findings at the American Society of Human Genetics annual meeting in Baltimore on Saturday, November 1.

Shen and his associates, S.J. Baek, K-D Lee and T. Fleisher, sequenced the gene for human thromboxane synthase, an enzyme that produces thromboxane A2—a compound that acts as a vasoconstrictor and induces platelet aggregation.

They found two repetitive sequences that significantly suppressed the expression of the gene, said Shen. A mutation in one of those regions could be a factor leading to overexpression of the thromboxane A2-producing enzyme, which in turn could result in the development of cardiovascular and kidney diseases due to excessive amounts of thromboxane A2.

Shen is a research associate professor of human genetics and a researcher in the UM Center for the Genetics of Asthma and Complex Diseases. He is an American Heart Association-Genentech special Awardee in Thrombosis.

ULTRASOUND CAN DIAGNOSE LETHAL DWARFISMS IN FETUSES

Ultrasound tests are a reliable way to diagnose rare but lethal genetic dwarfisms prenatally, University of Maryland School of Medicine genetics researchers say.

In a study of 27 cases at the University of Maryland Medical Center, Eric Wulfsberg, MD, and colleagues succeeded in diagnosing 93 percent of cases of lethal skeletal dysplasias, a rare group of genetic disorders that cause lethal dwarfism.

The success rate was nearly double that of studies done 10 to 15 years ago, in which ultrasonography during pregnancy identified fewer than 50 percent of cases.

The tests were much less helpful in making a specific diagnosis, which must be done in order to determine the risk of recurrence of the genetic defect.

"This has not changed much over time and shows a continuing need for clinical geneticists and radiologists to make post-natal diagnoses to make recurrence risk counseling possible," said Wulfsberg, associate professor and head of clinical genetics at the University of Maryland School of Medicine. Wulfsberg and colleagues will present their findings on Saturday, November 1, at the American Society of Human Genetics annual meeting in Baltimore.