Perinatal hypophosphatasia presenting as neonatal epileptic encephalopathy with abnormal neurotransmitter metabolism secondary to reduced co‐factor pyridoxal‐5′‐phosphate availability

• DOI: 10.1007/s10545-009-9012-y
• Publication Date: 2010-01-04T09:33:14Z
• Authors: Shanti Balasubram...; Frank Bowling; Kevin Carpenter; John Earl; Jeffrey Chaitow; James Pitt; Etienne Mornet; David Sillence; Carolyn Ellaway
• Keywords: Male; 0301 basic medicine; Brain Diseases, Metabolic; Infant, Newborn; Hypophosphatasia; Alkaline Phosphatase; Pyridoxaminephosphate Oxidase; 3. Good health; 03 medical and health sciences; Fatal Outcome; Phenotype; Treatment Outcome; Seizures; Pyridoxal Phosphate; Hypoxia-Ischemia, Brain; Mutation; Vitamin B Complex; Humans; Anticonvulsants; Biogenic Monoamines; Female; Genetic Predisposition to Disease; Vitamin B 6 Deficiency

AbstractWe describe two neonates presenting with perinatal hypophosphatasia and severe epileptic encephalopathy resulting in death. Both had increased levels of urinary vanillactate, indicating functional deficiency of aromatic amino acid decarboxylase, a pyridoxal‐5‐phosphate (PLP)‐dependent enzyme required for dopamine and serotonin biosynthesis. Clinical findings and results of subsequent metabolic investigations were consistent with secondary pyridoxine‐deficient encephalopathy. These patients highlight the importance of tissue non‐specific alkaline phosphatase in the neuronal PLP‐dependent metabolism of neurotransmitters. In addition, the disturbance of PLP metabolism appears to underlie the predominant neurological presentation in our patients. We recommend the measurement of serum alkaline phosphatase (ALP) during the assessment of perinatal seizures.