For example, Amish lethal microcephaly is caused by a mutation of the SLC25A19 (Solute carrier family 25 member 19), coding for a mitochondrial thiamine pyrophosphate carrier, which is a coenzyme for α-ketoglutarate dehydrogenase that operates in the TCA (tricarboxylic acid) cycle, (Kelley et al., 2002; Rosenberg et al., 2002). The gene discussed is SLC25A19; the disease is microcephaly.