OPD Syndrome
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Otopalatodigital syndrome spectrum disorders:
otopalatodigital syndrome types 1 and 2, frontometaphyseal
dysplasia and Melnick-Needles syndrome
Stephen P Robertson
The term otopalatodigital syndrome spectrum disorders is an umbrella category that includes four
phenotypically related conditions, otopalatodigital syndrome types 1 and 2, frontometaphyseal dysplasia
and Melnick–Needles syndrome. The phenotype of these conditions in the male ranges from a severe
perinatally lethal multiple malformation syndrome to a mild skeletal dysplasia. Most, but not all, instances
of these conditions are associated by mutations in the X-linked gene encoding the cytoskeletal protein
filamin A. Mutations in this gene are clustered, exhibit a strong genotype–phenotype correlation and are
presumed to exert their effect by a gain-of-function mechanism.
Keywords: otopalatodigital syndrome 1, otopalatodigital syndrome type 2, Melnick–Needles syndrome,
frontometaphyseal dysplasia, filamin A