Parkinsonism with Reduced Striatal Uptake on DAT-SPECT in a Patient Harboring a Novel KCND3 Variant.
Kimitaka Katanazaka, Mariko Takata, China Kanai et al.
✦ AI-curated · Sources linked
Case in brief
A Japanese patient with a novel KCND3 missense variant classified as a variant of uncertain significance had childhood-onset, slowly progressive cerebellar ataxia and asymmetric parkinsonism, a phenotype compatible with SCA19/22. Dopamine transporter SPECT showed reduced striatal uptake. Parkinsonian symptoms partially improved with dopaminergic therapy, although this response was supported mainly by clinical observation and had limited objective evidence. The cause of the parkinsonism remained uncertain: it could relate to the KCND3-associated phenotype, coexisting Lewy body disease, or contributions from both.
What made this case unusual
Reduced striatal uptake on dopamine transporter imaging had not previously been reported in patients with SCA19/22-related phenotypes, according to the authors.
Diagnostic / clinical pearl
In a patient with a KCND3-associated ataxia phenotype and parkinsonism, reduced striatal dopamine transporter uptake does not by itself establish whether the parkinsonism is related to the variant or to coexisting Lewy body disease.