See Table A. Genes and Databases for chromosome locus and protein.

See Molecular Genetics for information on variants detected in this gene.

Sequence analysis detects variants that are benign, likely benign, of uncertain significance, likely pathogenic, or pathogenic. Variants may include small intragenic deletions/insertions and missense, nonsense, and splice site variants; typically, exon or whole-gene deletions/duplications are not detected. For issues to consider in interpretation of sequence analysis results, click here.

The results of POR molecular genetic testing in 140 individuals with PORD have been reported (see Molecular Genetics). Homozygous or compound heterozygous pathogenic variants were detected by sequence analysis of POR in 266 alleles. In seven individuals, a large deletion or insertion was detected on one allele by gene-targeted deletion/duplication analysis [Soneda et al 2011, Krone et al 2012].

Gene-targeted deletion/duplication analysis detects intragenic deletions or duplications. Methods used may include a range of techniques such as quantitative PCR, long-range PCR, multiplex ligation-dependent probe amplification (MLPA), and a gene-targeted microarray designed to detect single-exon deletions or duplications.

Affected individuals have been reported with a single pathogenic variant and nearly complete absence of mRNA made from the allele in which no pathogenic variant was found [Fukami et al 2009]. Also reported: a pathogenic variant in a different gene involved in steroidogenesis: a female with a single POR pathogenic variant in addition to pathogenic variants in both copies of CYP21 [Scott et al 2007]; and, as part of a larger PORD cohort, three individuals (5 alleles) in whom a pathogenic sequence variant could not be found following direct sequencing and MLPA [Krone et al 2012].