Which dystonia is associated with the DYT1 mutation on chromosome 9, autosomal dominant inheritance, and typically begins in childhood?

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Multiple Choice

Which dystonia is associated with the DYT1 mutation on chromosome 9, autosomal dominant inheritance, and typically begins in childhood?

The key idea is a genetic, early-onset generalized dystonia. DYT1 is a mutation in the TOR1A gene on chromosome 9, inherited in an autosomal dominant pattern with incomplete penetrance. This combination produces early-onset dystonia that typically begins in childhood—often in a limb (like the leg or foot)—and can progress to generalized dystonia with abnormal postures and movements. This pattern—childhood onset, wide distribution, and the specific chromosome/ gene association—best fits early-onset primary dystonia, also called idiopathic torsion dystonia. Lesch-Nyhan syndrome is due to HGPRT deficiency and is X-linked, with a broader neurobehavioral picture than dystonia alone. Dopa-responsive dystonia arises from GCH1 mutations and characteristically shows diurnal fluctuation with a dramatic response to levodopa, not the DYT1-linked childhood-onset generalized pattern. Blepharospasm is a focal dystonia of the eyelids, usually later in life and not tied to the DYT1 mutation.

The key idea is a genetic, early-onset generalized dystonia. DYT1 is a mutation in the TOR1A gene on chromosome 9, inherited in an autosomal dominant pattern with incomplete penetrance. This combination produces early-onset dystonia that typically begins in childhood—often in a limb (like the leg or foot)—and can progress to generalized dystonia with abnormal postures and movements. This pattern—childhood onset, wide distribution, and the specific chromosome/ gene association—best fits early-onset primary dystonia, also called idiopathic torsion dystonia.

Lesch-Nyhan syndrome is due to HGPRT deficiency and is X-linked, with a broader neurobehavioral picture than dystonia alone. Dopa-responsive dystonia arises from GCH1 mutations and characteristically shows diurnal fluctuation with a dramatic response to levodopa, not the DYT1-linked childhood-onset generalized pattern. Blepharospasm is a focal dystonia of the eyelids, usually later in life and not tied to the DYT1 mutation.

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