In this study we show that (1) our specific cohort of PKAN patients has increased levels of acanthocytes compared to control donors (2) the degree of acanthocytosis varies among these patients despite of their identical Pank2 mutation and (3) donors being heterozygous with respect to this Pank2 mutation have an increased tendency to mild acanthocytosis. The gene discussed is PANK2; the disease is Constitutional hemolytic anemia due to acanthocytosis.