omodysplasia type 1
omodysplasia type 1A rare autosomal recessive skeletal dysplasia (OMIM:258315) characterised by severe congenital micromelia with shortening and distal tapering of the humeri and femora to give a club-like appearance. Typical facies include a prominent forehead, frontal bossing, short nose with a depressed broad bridge, short columella, anteverted nostrils, long philtrum and small chin.
Defects in GPC6, which encodes the cell surface proteoglycan glypican 6, cause omodysplasia type 1. Molecular changes include: point mutations of GPC6, leading to protein truncation, and larger genomic rearrangements resulting in exon deletions. All mutations in omodysplasia can lead to absence of functional glypican 6.