The Ehlers-Danlos syndrome: on beyond collagens
J. Clin. Invest. Jau-Ren Mao, et al. 107:1063 doi:10.1172/JCI12881 [
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Figure 3A novel deletion in the
C4/CYP21/TNX/CREB-rp locus is associated with EDS. The
C4 genes, the
CYP21 genes and part of
TNX are duplicated on chromosome 6. Dashed lines indicate the limits of the duplication event. The normal locus is shown in the top panel. Arrows indicate direction of transcription.
TNX is overlapped at its 3′ end by the
CYP21B (21B) gene encoding steroid 21-hydroxylase and, at its 5′ end, by CREB-related protein (
CREB-rp).
XA is a partial duplicate of
TNX that is a pseudogene transcribed but not translated in the human adrenal.
XA contains a 121 bp deletion (Δ) that truncates the open reading frame corresponding to
TNX.
CYP21A (21A) is a pseudogene. One-quarter of
CYP21B-deficient alleles carry a 30 kb deletion extending from
CYP21A to
CYP21B (middle panel). This creates a nonfunctional
CYP21AB fusion gene and deletes XA, but does not alter TNX. We described a similar deletion (lower panel) extending from
XA to
TNX that completely deletes
CYP21B and creates a
TNX/XA fusion gene. This deletion is associated with a new contiguous gene syndrome consisting of congenital adrenal hyperplasia, due to CYP21B deficiency, and EDS, due to TNX deficiency.
