Study may improve genetic counseling

STATE COLLEGE, Pa., July 1 (UPI) -- U.S. scientists studying how some human DNA mutations are involved in inherited diseases say their findings may affect the way genetic counseling is offered.

Pennsylvania State University researchers said their study has shed light on the processes that lead to human DNA mutations implicated in such diseases as tuberous sclerosis and neurofibromatosis type 1.

The scientists, led by Associate Professors Kateryna Makova and Francesca Chiaromonte, examined mutations in which small fragments of DNA are either added or subtracted from the genome. They said they found patterns in the DNA sequences immediately surrounding those mutations.

Chiaromonte said the study is the first to detect patterns in the DNA sequences adjacent to insertions and deletions of DNA fragments at the genome-wide scale.

"We were surprised to find that the patterns … are unique because scientists previously have lumped the two types of mutations together," graduate student Erika Kvikstad said. "What's striking is that most insertions and deletions are thought to occur by replication errors and, while this is a primary source generating the mutations, we discovered that recombination also is very important."

The scientists said that if it's know that certain diseases are more likely to be caused by recombination than by replication errors, physicians can provide better advice to couples who want to have children.

The research is detailed in the July issue of the journal Genome Research.