Hyper-beta-alaninemia associated with beta-aminoaciduria and gamma-aminobutyricaciduria, somnolence and seizures.
Hyper-beta-alaninemia was found in a somnolent, convulsing infant. Hyper-beta-aminoaciduria (beta-ala, betaAIB and taurine) was also observed, varying directly with plasma beta-alanine concentration. The beta-aminoaciduria is explained by the interaction between beta-alanine and a specific cellular-transport system with preference for beta-amino compounds. Gamma-aminobutyricaciduria was also observed, its excretion being independent of beta-alanine levels. Dietary modifications, pyridoxine, pantothenic acid and antibiotic therapy were not beneficial. Post-mortem tissues had elevated levels of beta-alanine and carnosine; GABA levels in brain were probably elevated for the age of the patient. A proposed block in beta-alanine-alpha-ketoglutarate transaminase would expand the free beta-alanine pool, thus increasing tissue carnosine. beta-Alanine is a central-nervous-system depressant. Associated inhibition of GABA transaminase and displacement of GABA from central-nervous-system binding sites would produce GABAuria and convulsions.
Scriver
C R
CR
Department of Pediatrics, McGill University, Montreal, Quebec.
Pueschel
S
S
Davies
E
E
D000612:4-Aminobutyrate Transaminase / Q000378:metabolism; D000592:Amino Acid Metabolism, Inborn Errors / Q000150:complications / Q000378:metabolism / Q000628:therapy; D006970:Disorders of Excessive Somnolence / Q000209:etiology; D006801:Humans; D007223:Infant; D008297:Male; D012640:Seizures / Q000209:etiology; D013654:Taurine / Q000652:urine; D015091:beta-Alanine / Q000097:blood* / Q000378:metabolism / Q000652:urine; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D015091:beta-Alanine; D013654:Taurine; D005680:gamma-Aminobutyric Acid; D000612:4-Aminobutyrate Transaminase