UCD.- Argininosuccinic aciduria. Three clinical forms. Argininosuccinate lyase deficiency
Incidence
Second most common UCD. Approx. 1:70,000. There are 3 forms: neonatal, early infantile and late infantile or early childhood
Clinical Characteristics
Mental retardation, poorly formed hair. Recurrent generalized seizures, ataxia, hepatomegaly. Neonates (most severe form) have poor feeding, lethargy, hypotonia and seizures, usually die < 2 weeks. Often coma with hyperammonemia.
Precipitants
Protein loading, intercurrent infections frequently precipitate hyperammonemia..
Provocation Tests
Protein loading test: Give breakfast with 1 gr protein/kg and measure ammonia, aminoacids, urine orotic acid q 2 h x 6 h. Orotic acid will go up.
Diagnostic Procedures
Orotic acid in urine, GC/MS in urine. EB- liver. Ammonia high in blood.