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We read with interest the report by Janot et al describing an individual with elevated steroid precursors suggestive of 11β-hydroxylase deficiency and clinical features consistent with congenital adrenal hyperplasia (CAH).1 A single paternally inherited frameshift variant in CYP11B1 prompted manual scrutiny of read alignments and the identification of an intragenic inversion NC_000008.11(NM_000497.4):c.[892_1121+7 inv;1121+8_1121+9del]. This inversion had evaded detection by both Sanger sequencing and next-generation sequencing (NGS) analysis using a custom bioinformatics pipeline. Using data from the 100 000 Genomes Project (100kGP)2 and UK Biobank (UKB),3 we use existing structural variant (SV) calls and a nearby tagging variant to establish that this inversion is relatively widespread, algorithmically detectible from short-read sequencing data and likely arose from a shared ancestor ~90 generations ago.