Un trastorno poco frecuente del ciclo de la urea en un recién nacido: deficiencia de N-acetilglutamato sintasa / A rare urea cycle disorder in a neonate: N-acetylglutamate synthetase deficiency

Los trastornos del ciclo de la urea (TCU) son enfermedades hereditarias con un posible desenlace desfavorable por hiperamoniemia grave. Se informa de una bebé con deficiencia de N-acetilglutamato sintasa (NAGS), quien tenía succión débil e hipotonicidad. Al examinarla, se observó hepatomegalia. El hemograma, los análisis y la gasometría eran normales, y las proteínas de la fase aguda, negativas. En los análisis, no se observaron cetonas en sangre, pero sí concentraciones elevadas de amoníaco. Las pruebas metabólicas no fueron concluyentes. Se inició el tratamiento de emergencia inmediatamente y recibió el alta el día 15 después del ingreso. Se confirmó deficiencia de NAGS mediante análisis de ADN. La paciente no tiene restricciones alimentarias ni toma medicamentos, excepto N-carbamil glutamato (NCG). La deficiencia de NAGS es el único TCU que puede tratarse específica y eficazmente con NCG. La detección temprana permite iniciar un tratamiento temprano y evitar los efectos devastadores de la hiperamoniemia

Urea cycle disorders (UCD), are genetically inherited diseases that may have a poor outcome due to to profound hyperammonemia. We report the case of a baby girl diagnosed as N-acetylglutamate synthase (NAGS) deficiency.The patient was evaluated due to diminished sucking and hypotonicity. Physical examination showed hepatomegaly. Complete blood count, biochemical values and blood gas analyses were normal, acute phase reactants were negative. Further laboratory analyses showed no ketones in blood and highly elevated ammonia. Metabolic tests were inconclusive. Emergency treatment was initiated immediately and she was discharged on the 15th day of admission. NAGS deficiency was confirmed by DNA-analysis. She is now without any dietary restriction or other medication, except N-carbamylglutamate (NCG).NAGS deficiency is the only UCD which can be specifically and effectively treated by NCG. Early recognition of disease will lead to early treatment that may prohibit devastating effects of hyperammonemia

Lysinuric Protein Intolerance Presenting with Recurrent Hyperammonemic Encephalopathy.

Background: Lysinuric protein intolerance is an inherited disorder of transport of cationic amino acids, causing amino aciduria. Case characteristics: A 3-year-old boy with 12 month history of episodic change in behavior (decreased sleep, poor interaction), stunted growth and hyperammonemia. Outcome: Genetic analysis revealed a homozygous mutation, c.158C>T (p.Ser53Leu) in exon 1 of SLC7A7 gene.With appropriate management of hyperammonemia episodes, his neurodevelopmental outcome is normal. Message: Lysinusic protein intolerance is a potentially treatable disorder and should not to be missed.