Inherited and de novo variants in young females potentially associated with pelvic organ prolapse.

Abstract

Pelvic organ prolapse is a common condition usually affecting postmenopausal women, but it is also seen in about 10% of women aged 20 to 39 years. In young females, genetic factors seem to be of particular interest. This study aimed to identify inherited and de novo variants relevant to pelvic organ prolapse in young females without a family history. A total of 25 women aged ≤40 years with parity ≤2 and Pelvic Organ Prolapse Quantification stage ≥II were included in the study. Moreover, females had no history of pelvic organ prolapse and any previous history of urogynecological surgery. A trio-based exome analysis was performed on patients and both their parents. Bioinformatic analysis of raw whole exome sequencing data and genetic variant prioritization were performed using in-house bioinformatic pipeline. The ClinVar database, GeneCard, and the Human Protein Atlas were used to determine clinical significance, disease associations, and linked phenotypes of the genetic variants. The impact of causative genetic variants on protein structure and function was assessed using various prediction tools including Sorting Intolerant From Tolerant, PolyPhen2, MutPred2, Phyre2, and SNPeffect 4.0. To determine the molecular interaction network of the proteins, Search Tool for the Retrieval of Interacting Genes database was applied. The mean age of women was 33.50 (±3.07) years, the mean body mass index value was 21.80 (±2.07), and the number of parity was 1.76 (±0.44). In the study group, 18 of 25 women required surgical treatment. Whole exome sequencing analysis identified 76 de novo variants, but only 19 were missense and 2 were nonsense variants. Three genetic variants in CSPG4, ITGA7, and MT-CO3 genes appear potentially relevant to pelvic organ prolapse. Interestingly, paternally inherited variants in SGCG, CYP24A1, and TK2 genes likely related to pelvic organ prolapse were found in carriers of new de novo variants. In this study, no common genetic variants were found in the female group. Potentially causative patient-specific variants were found in genes related to extracellular matrix, mitochondria, or skeletal muscle conditions. The uncovered genetic variants presumably disrupt the functioning of muscles and mitochondria, which may consequently lead to pelvic floor dysfunction in young women.