Clinical and genetic analysis of cytochrome P450 oxidoreductase (POR) deficiency in a female and the analysis of a novel POR intron mutation causing alternative mRNA splicing

Abstract

Objective To characterize the clinical features of a female with P450 oxidoreductase (POR) deficiency and to investigate the underlying mechanisms of POR inactivation. Methods The proband was a 35-year-old woman with primary infertility and menstrual irregularity. The reproductive endocrine profile was evaluated. DNA sequencing was conducted for the identification of POR gene mutation. RT-PCR was performed to confirm the impact of the mutation on POR mRNA. A molecular model was built for the structural analysis of mutant POR protein. ResultsThe evaluation of reproductive endocrine profile revealed elevation of serum follicle-stimulating hormone (11.48 mIU/ ml), progesterone (11.00 ng/ml), 17α-hydroxyprogesterone (24.24 nmol/l), dehydroepiandrosterone (6300 nmol/l), and androstenedione (3.89 nmol/l) and decreased estradiol (36.02 pg/ml). Sequencing of the POR gene showed the female was a compound heterozygote of the paternal P399_E401 deletion and a novel maternal IVS14-1G>C mutation. Functional analysis revealed IVS14-1G>C mutation caused alternative splicing of POR mRNA, with the loss of 12 nucleotides in exon 15 (c.1898_1909delGTCTACGTCCAG). Also, the resulting mutant POR protein had a V603_Q606 deletion, which inactivated the nucleotide-binding domain of NADPH in POR protein (K602_Q606). Conclusion The mutation IVS14-1G>C of the POR gene could cause alternative splicing of POR mRNA and dysfunction of the resulting POR protein. Under proper IVF strategy with glucocorticoid therapy and endometrial preparation, females with mild POR deficiency still have the opportunity to have a live birth.Keywords Cytochrome P450 oxidoreductase deficiency . Live birth . In vitro fertilization . Alternative splicing . Compound heterozygote Précis Clinical and genetic analysis of POR deficiency in a female.

Antley-Bixler syndrome arising from compound heterozygotes in the P450 oxidoreductase gene: a case report

“…Five cases in the Chinese cohort carried homozygous p.R457H, and the P399_E401 deletion reported first in Turkish families was found in one Chinese case (39). To date, p.A287P, which has a high prevalence in Caucasian populations, has not been detected in Chinese PORD patients (13,14,25).…”

“…The majority of reported PORD cases are of Japanese or European descent, and more than 90 mutations in the POR gene have been identified (http://www.hgmd. cf.ac.uk/ac/index.php) (11,13,14,20,25,(28)(29)(30)(31). There have been few PORD case cohorts reported in China (4).…”

“…There have been few PORD case cohorts reported in China (4). Hence, we performed a genotype-phenotype correlational analysis on 21 Chinese patients identified with POR gene mutations, based on the literature published in Chinese or English (Table 1) (1)(2)(3)(4)7,13,(32)(33)(34)(35)(36)(37)(38).…”

“…Indeed, deficiencies in the steroidogenic P450 enzymes including CYP17A1, CYP21A2, and CYP51A1 are most commonly associated with ABS (2,7,10). To date, a number of mutations, including missense, nonsense, splice site, and frameshift, as well as microdeletions or microduplications have been reported in the POR gene region (11)(12)(13)(14). Previous studies have shown that the A287P missense POR mutation resulted in a 40% residual POR activity and has been proved to be the most frequent mutation in Caucasian patients, whereas R457H occurred in over 70% of Japanese patients and led to a 3% residual POR activity (15)(16)(17)(18).…”

Infertility treatment for Chinese women with P450 oxidoreductase deficiency: Prospect on clinical management from IVF to FET

“…PCOS is always accompanied by hyperandrogenemia, while PORD female adults mainly exhibit impaired sex hormone synthesis with combined 17ahydroxylase and 21-hydroxylase deficiency (11). To date, only five women with PORD became pregnant after assisted reproductive techniques (ARTs) have been reported (10,(12)(13)(14). The in vitro fertilization (IVF) and frozen embryo transfer (FET) protocols have not been well summarized.…”