Autosomal dominant thrombocytopenia caused by a heterozygous CYCS variant: a new family and literature review.
Liping Luo, Hualei Luo, Tingyan He et al.
✦ AI-curated · Sources linked
Case in brief
Four affected members of a Chinese family across three generations had isolated mild-to-moderate thrombocytopenia, with platelet counts of 54 to 83 × 10⁹/L and normal platelet size and morphology. Thromboelastography showed decreased maximum amplitude; two individuals had mildly reduced responses to several platelet agonists, while surface glycoprotein expression was normal. Sequencing identified a heterozygous CYCS missense variant, c.292T>C (p.Y98H), that cosegregated with thrombocytopenia. Structural prediction suggested protein destabilization. The findings supported CYCS-associated thrombocytopenia (THC4).
What made this case unusual
The family carried the rare CYCS p.Y98H variant, with detailed platelet-function findings despite normal platelet morphology and surface glycoprotein expression.
Diagnostic / clinical pearl
In familial isolated thrombocytopenia with normal platelet size and morphology, CYCS-related THC4 is a diagnostic consideration; genetic testing can establish the association when routine platelet findings are not distinctive.