Finally, epileptic seizures resulting from TNAP deficiency are likely due to lack of pyridoxal phosphate dephosphorylation in the serum [37, 38], which is an essential step in pyridoxal entry into cells and synthesis of gamma-amino butyric acid (GABA) [39, 40]. Akp2-null mice die from apnea associated with epileptic seizures before weaning [40, 41], whereas in humans severe forms of HPP are lethal perinatally, due to respiratory complications linked to hypoplastic lungs and rachitic deformities of the chest, apnea [42], and/or to fatal encephalopathy [30, 31]. The gene discussed is ALPL; the disease is hypophosphatasia.