OPD Syndrome         
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Oto-palato-digital syndrome, type II: report of
three cases with further delineation of the
chondro-osseous morphology

Savarirayan R, Cormier-Daire V, Unger S, Lachman RS, Roughley PJ, Wagner SF,
Rimoin DL, Wilcox WR. Medical Genetics Birth Defects Center, Steven Spielberg
Pediatrics Research Center, Cedars-Sinai Burns and Allen Research Institute, Los
Angeles, California 90048, USA.

Oto-palato-digital syndrome type II (OPD II) is a lethal X-linked skeletal dysplasia with
pleiotropic manifestations. The basic defect is not known. There has been only one
detailed report of the chondro-osseous abnormalities in this condition describing
abnormal periosteal ossification in a single case [1990: Am J Med Genet 36:226-231].
We report on three cases of OPD II emphasizing the chondro-osseous morphology.
Although endochondral ossification was normal, periosteal ossification was defective
with islands of cortical bone aplasia and hyperplasia of the periosteum. The trabecular
bone was also extremely poorly formed and markedly hypercellular. Both membranous
ossification and bone remodeling appear to be defective in OPD II and should account
for part of the observed phenotype. The biglycan gene maps to Xq28 and is involved in
bone formation, but was excluded as a candidate by direct sequencing of cDNA in one
case. Copyright 2000 Wiley-Liss, Inc. PMID: 11102922 [PubMed - indexed for