OPD Syndrome         
Family Resource Network
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