Treatment with L-arginine improves neuropsychological disorders in a child with creatine transporter defect.

Creatine transporter deficit (CT1) is an inherited metabolic disorder that causes mental retardation, epilepsy, speech, language and behavioral deficits. Until now, no treatment has been proven to be successful for this condition. We describe 1-year follow-up study of a child, aged 9.6 years, with CT1 defect, on oral supplementation with L-arginine, a precursor of creatine synthesis. Under supplementation, he showed a noticeable improvement of neurological, language and behavioral status and an increase of brain creatine and phosphocreatine documented with magnetic resonance spectroscopy. The results suggest that children with CT1 disorder show some residual adaptive plasticity for certain functions even at quite an advanced age. Further trials with higher L-arginine dosages and more protracted treatment are encouraged.

Mental retardation and verbal dyspraxia in a new patient with de novo creatine transporter (SLC6A8) mutation.

We report on a 9.5-year-old Italian boy affected by creatine transporter deficit (CT1), due to a de novo mutation in SLC6A8 gene. The patient was investigated by means of a comprehensive neuropsychological protocol and presented with an unusual alteration of speech and expressive-language function, associated with mental retardation, that differed from CT1 patients described to date. In particular, he exhibited a developmental apraxia of speech (DAS) with motor planning and execution deficit, while receptive language was consistent with his mental age.

Fifteen-year follow-up of Italian families affected by arginine glycine amidinotransferase deficiency.

BACKGROUND: Arginine:glycine amidinotransferase deficiency (AGAT-d) is a very rare inborn error of creatine synthesis mainly characterized by absence of brain Creatine (Cr) peak, intellectual disability, severe language impairment and behavioural disorder and susceptible to supplementary Cr treatment per os. Serial examinations by magnetic resonance spectroscopy are required to evaluate Cr recovery in brain during treatment of high doses of Cr per os, which have been proved beneficial and effective in treating main clinical symptoms. A long term study with detailed reports on clinical, neurochemical and neuropsychological outcomes of the first Italian patients affected by AGAT-d here reported can represent a landmark in management of this disorder thus enhancing medical knowledge and clinical practice. RESULTS: We have evaluated the long term effects of Cr supplementation management in four Italian patients affected by AGAT-d, correlating specific treatments with serial clinical, biochemical and magnetic resonance spectroscopy examinations as well as the neuropsychological outcome by standardized developmental scales. Consecutive MRS examinations have confirmed that Cr depletion in AGAT-d patients is reversible under Cr supplementation. Cr treatment is considered safe and well tolerated but side effects, including weight gain and kidney stones, have been reported. CONCLUSIONS: Early treatment prevents adverse developmental outcome, while patients diagnosed and treated at an older age showed partial but significant cognitive recovery with clear improvements in adaptive functioning.

Arginine:glycine amidinotransferase (AGAT) deficiency in a newborn: early treatment can prevent phenotypic expression of the disease.

Arginine:glycine amidinotransferase deficiency is a treatable inborn error of creatine synthesis, characterized by mental retardation, language impairment, and behavioral disorders. We describe a patient in whom arginine:glycine amidinotransferase was diagnosed at birth and treated at 4 months with creatine supplementation. In contrast with his 2 older sisters, he had normal psychomotor development at 18 months.