Stuttering, Familial Persistent, 3

Description

Stuttering is a disorder of the flow of speech characterized by involuntary repetitions or prolongations of sounds or syllables, and by interruptions of speech known as blocks (summary by Raza et al., 2010).

For a general phenotypic description and a discussion of genetic heterogeneity of stuttering, see STUT1 (184450).

Clinical Features

Raza et al. (2010) reported a consanguineous Pakistani family in which 5 individuals above 8 years of age had persistent stuttering for more than 6 months.

Inheritance

The transmission pattern of persistent stuttering in the family reported by Raza et al. (2010) was consistent with autosomal recessive inheritance.

Mapping

By genomewide linkage analysis followed by fine mapping in a consanguineous Pakistani family with stuttering, Raza et al. (2010) found linkage to a region on chromosome 3q13.2-q13.33 (maximum 2-point lod score of 4.23 at marker D3S1310). One individual with the associated diplotype did not stutter, suggesting incomplete penetrance. Sequencing of the coding exons of the DRD3 gene (126451) did not identify any genetic variations.