['To identify the underlying molecular basis of a familial developmental disorder characterized by chorea, marked speech delay, and learning difficulties in 4 sisters from a consanguineous family.', 'Whole-exome analysis of DNA of the 2 older patients followed by Sanger sequencing of the mutated exon in all family members.', 'A homozygous deleterious mutation, p.C291X, was identified in the GPR88 gene in both exome analyses. The mutation segregated with the disease in the family and was absent from a large cohort of controls.'] Is deleterious mutation in GPR88 associated with chorea , speech delay , and learning disabilities?