The importance of the multiplex ligation-dependent probe amplification in the identification of a novel two-exon deletion of the NR5A1 gene in a patient with 46,XY differences of sex development.
Nuclear receptor subfamily 5 group A member 1/Steroidogenic factor 1 (NR5A1; SF-1; Ad4BP) mutations cause 46,XY disorders of sex development (DSD), with phenotypes ranging from developmentally mild (e.g., hypospadias) to severe (e.g., complete gonadal dysgenesis).
Literature search confirmed twelve other cases of this scenario, namely, severe under-virilization in utero followed by spontaneous virilization around puberty in NR5A1-related 46,XY DSD.
Our results suggest that the broad phenotype in these heterozygous NR5A146,XY DSD subjects may well be explained by an oligogenic mode of inheritance, in which multiple hits, individually non-deleterious, may contribute to a DSD phenotype unique to each heterozygous SF-1/NR5A1 individual.
In the present study, we describe the impact of five NR5A1 variants (three novel: p.Arg39Cys, p.Ser32Asn, and p.Lys396Argfs*34; and two previously described: p.Cys65Tyr and p.Cys247*) on protein function, identified in seven patients with 46,XY DSD.
The first human NR5A1 mutation was a heterozygous de novo p.G35E variant identified in a patient with disorder of sex development (DSD) 46,XY and primary adrenal insufficiency.
Mutations in NR5A1 have been reported as a frequent cause of 46,XY disorders of sex development (DSD) associated to a broad phenotypic spectrum ranging from infertility, ambiguous genitalia, anorchia to gonadal dygenesis and female genitalia.
We provide new evidence of this involvement, describing a novel heterozygous non-sense NR5A1 mutation in a 46,XY-DSD with polysplenia female proband and her father, who had hypospadias and asplenia.
The NR5A1p.Arg92Gln variant, which has thus far only been seen in a family with 46,XY DSD, most likely contributes to the ovotesticular DSD in this case.
For the clinical utility of NR5A1 gene mutations, more comprehensive studies with large 46,XY DSD patient series in different populations are suggested.
Based on this finding, we screened patients with unexplained 46,XY DSD (n = 11), proximal hypospadias (n = 21) and 46,XX POF (n = 36) for possible NR5A1 copy-number variations (CNVs) via multiplex ligation-dependent probe amplification (MLPA), but did not identify any additional CNVs involving NR5A1.
In order to ascertain whether or not the histological features were the characteristics of NR5A1 mutations, we screened the testicular histology of 242 patients with 46,XY DSD and then subsequently assessed NR5A1 mutations.