In an ATPase activity study, Na and K concentrations were studied in the platelets of normal subjects and patients with Down syndrome; the results showed that the patients’ platelet K content was significantly decreased (13.12±0.48 μg per 109 platelets vs. 19.78±0.72 μg per 109 platelets; p<0.001) [43]. Here, DNAH8 is linked to Down syndrome.