HOXA10 and HOXA13 sequence variations in human female genital malformations including congenital absence of the uterus and vagina

Abstract

Congenital genital malformations occurring in the female population are estimated to be 5 per 1000 and associate with infertility, abortion, stillbirth, preterm delivery and other organ abnormalities. Complete aplasia of the uterus, cervix and upper vagina (Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome) has an incidence of 1 per 4000 female live births. The molecular etiology of congenital genital malformations including MRKH is unknown up to date. The homeobox (HOX) genes HOXA10 and HOXA13 are involved in the development of human genitalia. In this investigation, HOXA10 and HOXA13 genes of 20 patients with the MRKH syndrome, 7 non-MRKH patients with genital malformations and 53 control women were sequenced to assess for DNA variations. A total of 14 DNA sequence variations (10 novel and 4 known) within exonic and untranslated regions were detected in HOXA10 and HOXA13 among our cohorts. Four HOXA10 and two HOXA13 DNA sequence variations were found solely in patients with genital malformations. In addition to mutations resulting in synonymous amino acid substitutions, in the HOXA10 gene a missense mutation was identified and predicted by computer analysis as probably damaging to protein function in two non-MRKH patients, one with a bicornate and the other patient with a septated uterus. A novel exonic HOXA10 cytosine deletion was also identified in a non-MRKH patient with a septate uterus and renal malformations resulting in a premature stop codon and loss of the homeodomain helix 3/4. This cytosine deletion and the missense mutation in HOXA10 were analysed by real time PCR and sequencing, respectively, in two additional larger cohorts of 103 patients with MRKH and 109 non-MRKH patients with genital malformations. No other patients were found with the cytosine deletion however one additional patient was identified regarding the missense mutation. Rare DNA sequence variations in the HOXA10 gene could contribute to the misdevelopment of female internal genitalia.