XK and McLeod neuroacanthocytosis syndrome: Molecular weight of 50.9 kDa10 transmembrane segmentsShort N-terminal domain (intracellular)Large C-terminal domain (intracellular)A large hydrophilic loop (Figure 3)Single cysteine residue that binds covalently to Cys72 on KellLoss of XK leads to McLeod syndrome that has X-linked inheritance