Complex V of the respiratory chain (also termed ATP Synthase) is the final step in this process cellular energy production in the form of ATP molecules. TMEM70 gene defects were recently shown to cause ATP synthase deficiency in several patients of gypsy origin. In this study we describe six Israeli patients caused by four novel mutations in the TMEM70 gene. Their disease is highlighted by congenital hypertrophic cardiomypathy, severe life threatening episodes of lactic acidemia and variable degree of neurologic impairment. The disease is accompanied by significant infantile mortality and major morbidity in the survivors. The study confirms TMEM70 gene deleterious mutations as the most common cause of ATP synthase deficiency and suggests sequence analysis of this gene in patients with typical clinical features.  (By Dr. Ronen Spiegel, http://jmg.bmj.com/content/early/2010/12/08/jmg.2010.084608?papetoc=)