MON-060 P-450 Oxidoreductase Deficiency with Antley Bixler Phenotype: A Novel Mutation

Abstract

IntroductionWe present first case of 46 XY Disorder of Sex Development (DSD) from India due to P-450 Oxidoreductase Deficiency with Novel variant (p.Ala541Thr) in a heterozygous state.Case Discussion6 months old boy presented with ambiguous genitalia since birth. No history of neonatal crisis, failure to thrive and pigmentation of skin, maternal virilisation or drug ingestion during pregnancy. On examination: weight 6.2 Kg (3rd centile), height 64 cm (3rd centile), MPH-170 (25-50th centile), head circumference 38 cm (−2.7 SD), vitals stable, trigonocephaly with fused anterior and posterior fontanelle, prominent pointed forehead, midfacial hypoplasia, up slanting eyes, hypertelorism and low set ears were present. Genitalia: 1.5 cm phallus like structure with foreskin, chordee, single perineal opening in form of peno-scrotal hypospadias, bifid scrotum with poor rugosity and poor pigmentation and both gonads (1 ml) were palpable in labio-scrotal fold with external masculinization score (EMS), 6/12 and Prader stage 4.Investigations showed normal electrolytes and blood sugar, High basal ACTH, post stimulation cortisol 14mcg/dl, Basal 17-OHP was 8.6 ng/ml and post stimulation 12ng/ml, with low DHEAS 36.4 mcg/dl and androstenedione 0.42 ng/ml, LH 16.09 mIU/ml (elevated), FSH 2.97 mIU/ml (normal) and low Testosterone for his age. T/DHT 9.6 (normal<10) and Testosterone /Androstenedione ratio 0.95 (normal >0.8). Abdominal and Pelvic imaging showed normal adrenal glands and absent female internal genitalia, bilateral testis in labio-scrotal fold (right testis-6x6.5x11 mm, left testis-6.6x7x10 mm), corpora cavernosa and bifid scrotum. NCCT Head showed metopic craniosynostosis with trigonocephaly and hypotelorism. Skeletal survey showed bowing of femora. 20 cell Karyotype of peripheral blood lymphocyte was 46 XY. NGS was done of the POR gene, which revealed a heterozygous missense variation in exon 13 of the POR gene variant (p.Ala541Thr) which has not been reported yet.The patient was initiated hydrocortisone, fludrocortisone, DHT gel and corrective surgery is planned.Clinical learningAlthough in PORD classically the inheritance is generally autosomal recessive, but manifesting heterozygotes are not uncommon1. This case also shows the value of Next gen sequencing and the role it can play in DSD1. Scott RR, Gomes LG, Huang N, Van Vliet G, Miller WL. Apparent manifesting heterozygosity in P450 oxidoreductase deficiency and its effect on coexisting 21-hydroxylase deficiency. J Clin Endocrinol Metab. 2007;92:2318–2322