GNAL mutations cause adult-onset primary dystonia

• OBJECTIVE: Identification of the causal mutation in an African-American family with adult-onset primary dystonia. BACKGROUND: The vast majority of patients with dystonia are adults with primary focal or segmental anatomical distributions. Familial and sporadic dystonia appear to share the same genetic etiological background. Although approximately 10% of probands have at least one first- or second-degree relative with dystonia, large pedigrees suited for linkage analysis are uncommon. In previous work, we excluded THAP1 and TOR1A mutations in an African-American family with clinical phenotypes that included cervical, laryngeal and hand-forearm dystonia. DESIGN/METHODS: Linkage and haplotype analyses were combined with solution-based whole-exome capture and massively parallel sequencing in order to identify the causal mutation (GNAL, c.913G>T) in our African-American family with dystonia. High resolution melting and Sanger sequencing were used to screen 768 additional subjects with primary cervical or segmental dystonia for sequence variants in GNAL. RESULTS: The missense mutation in GNAL (c.913G>T, p.V305F) was found to co-segregate with dystonia in our African-American pedigree. GNAL encodes guanine nucleotide-binding protein G(olf), subunit alpha [Gα(olf)]. Gα(olf) is highly expressed in the olfactory bulb, striatum and cerebellar Purkinje cells. Gα(olf) plays a role in olfaction, coupling D1 and A2a receptors to adenylyl cyclase, and histone H3 phosphorylation. Screening identified two additional pedigrees with GNAL mutations (c.822-823insA [p.R275T∗13] and c.964C>T [p.R322∗]). None of these sequence variants were found in 760 controls. CONCLUSIONS: Mutations in GNAL are causally-associated with adult-onset primary cervical and segmental dystonia. The prominent expression of Gα(olf) in striatum and cerebellar Purkinje cells points to potential sites of functional pathology in primary dystonia.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Neurologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Neurology (hsv//eng)

Nyckelord

protein G

guanine nucleotide binding protein

histone

adenylate cyclase

receptor

adult

dystonia

neurology

mutation

African American

pedigree

corpus striatum

Purkinje cell

segmental dystonia

forearm

olfactory bulb

phenotype

alpha chain

linkage analysis

second-degree relative

missense mutation

screening

phosphorylation

high resolution melting analysis

exome

smelling

haplotype

human

pathology

patient

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