omodysplasia

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Epidemiology

rare

autosomal recessive
associated with defects in GPC6 (type 1)
- point mutations leading to protein truncation, as well as larger genomic rearrangements resulting in exon deletions, have been found in family segregating omodysplasia type 1
- all mutations identified in individuals affected by omodysplasia could lead to the absence of a functional GPC6 protein, the mutant RNAs being suspected to be nonsense-mediated mRNA decay (NMD) targets
- even if the mRNA escapes NMD & is translated, all mutations are expected to disrupt the three-dimensional protein structure and often to abolish multiple highly conserved Cys

severe congenital micromelia with
shortening & distal tapering of the humerus & femur to give a club-like appearance
typical facial features include a prominent forehead, frontal bossing, short nose with a depressed broad bridge, short columella, anteverted nostrils, long philtrum, & small chin.