Such phenotypes range from severe myopathy, cardiomyopathy and neutropenia (TAZ) to multisystemic disorders comprising progressive encephalopathy and neurodevelopmental regression (PNPLA8, CRLS1, TAMM41, PTPMT1).10,16,17,64 Cardiolipin is particularly abundant in heart tissue; however, cardiac manifestations were not observed in the herein reported subjects. Here, PTPMT1 is linked to neutropenia.