A growing body of evidence suggests that genes figure significantly in the risk for pelvic organ prolapse (POP), researchers said here at the American Urogynecologic Society 31st Annual Scientific Meeting.
In the first genome-wide association analysis for POP, Peggy Norton, MD, from the University of Utah School of Medicine in Salt Lake City, presented evidence that at least 6 single-nucleotide polymorphisms (SNPs) are significantly associated with POP.
“These results provide additional evidence for a genetic contribution to POP,” Dr. Norton said in an oral presentation at the conference.
The study subjects were 115 white women who had been treated for POP at the university clinic between 1996 and 2008, all of whom had a family history of pelvic floor disorders. Of those, 113 women had undergone surgery at least once. Their mean age at diagnosis was 48.8 years (range, 21 to 75 years), and mean parity was 4.3 (range, 0 to 13). They had a mean body mass index of 26.6 kg/m2 (range, 16 to 47 kg/m2).
Most of the participants had morbidities other than POP, Dr. Norton said. “These are the women you see in your practice. In addition to POP, 72 had been treated for stress urinary incontinence, 37 for overactive bladder, and 13 for hernias.”
The patients in the study were genotyped using genome-wide association studies (GWAS), which are commonly used to look for genetic contributions to complex diseases. “GWAS is becoming popular because it can be performed on unrelated individuals,” Dr. Norton explained.
The study subjects were compared with 2976 control subjects drawn from the general population. The control group was racially similar to the study group, but the prevalence of POP in the control group was unknown.
The investigators also analyzed data from a local control group (n = 264), which consisted of patients who had been genotyped for breast cancer, prostate cancer, melanoma, and others who participated in the International HapMap Project, a multicountry effort to identify and catalogue human genetic differences and similarities. The HapMap control subjects were drawn from the Centre d’Étude du Polymorphisme Humain (CEPH) pedigree, consisting of 30 white trios from Utah.
Using GWAS techniques, Dr. Norton and her colleagues identified 133 SNPs. Further analysis determined that 7 of those had a significant association with POP when compared with genome analysis of the control group. The SNPs were located on chromosomal regions 4q21, 8q24, 9q22, 11q14, 15q11, 20p13, and 21q22. Analysis of data from the HapMap control group revealed that all except the SNP at 20p13 retained a significant association with POP.
The choice of control groups for this study was important, said Ingrid Nygaard, MD, professor of obstetrics and gynecology at the University of Utah School of Medicine, and comoderator of the session at which Dr. Norton presented her research. She noted that some of the women in the control group might have had POP, and “it seems to me this would have affected your results.” Dr. Nygaard was not involved in this study.
Some of the control subjects might indeed have had POP, Dr. Norton said. They were selected because they were white women of northern European descent, and currently “that’s about as close as you can come” to a genetic match. “The more people who begin working in this area, the more we’ll be able to identify [appropriate] controls.”
Ultimately, POP probably will turn out to be the result of several genetic variations, perhaps affecting the patient’s ability to synthesize connective tissue, she said. “Right now, we can tell patients we’re working on it, and if it’s running in families, we will be able to give better advice to the next generation,” Dr. Norton observed.
Drs. Norton and Dr. Nygaard have disclosed no relevant financial relationships.
American Urogynecologic Society (AUGS) 31st Annual Scientific Meeting: Abstract 1. Presented October 20, 2010.
Norra MacReady for original article click here.
J. Kyle Mathews, MD
Plano Urogynecolgy Associates
Plano OBGYN Associates
Tags: American Urogynecologic Society, Annual Scientific Meeting, Annual Scientific Meeting Abstract, cancer, Dr. Mathews, Genetic, GWAS, Peggy Norton, pelvic organ prolapse, Plano Urogynecolgy Associates, POP, SNP, women | Category: News & Education, Pelvic Reconstructive Surgery & Urogynecology |