ABSTRACT
The aim of the study was to investigate the prevalence and mechanisms of development of carnitine deficiency in patients with lysinuric protein intolerance (LPI). In our cohort of 37 Finnish patients with LPI, 8 (8-52 years of age) have been diagnosed with hypocarnitinemia. Their free and total serum carnitine levels, acyl carnitine profiles, renal function, diet, and medication were compared with the data from 8 age- and sex-matched patients with LPI not treated with carnitine supplementation. In patients with LPI, hypocarnitinemia was strongly associated with female sex, renal insufficiency, and the use of ammonia-scavenging drugs. Of the 8 hypocarnitinemic patients, 3 complained of muscle weakness, and their symptoms disappeared during carnitine supplementation. Oral lysine supplementation did not correct hypocarnitinemia in our patients. The patients with LPI are at considerable risk for carnitine deficiency. Supplementation of hypocarnitinemic LPI patients with oral L-carnitine improved serum total carnitine values, but the ratio of free and total carnitine remained subnormal in all supplemented patients except one. Furthermore, decreased ratio of free and total serum carnitine was common even in LPI patients with normal total serum carnitine concentration.
Subject(s)
Amino Acid Metabolism, Inborn Errors/metabolism , Carnitine/deficiency , Lysine/urine , Adolescent , Adult , Amino Acid Metabolism, Inborn Errors/therapy , Child , Dietary Supplements , Female , Humans , Male , Middle AgedABSTRACT
An 8-year-old boy was referred to our hospital because of learning disabilities. His general cognitive functions were below the level for age, and he was diagnosed with dysphasia. The boy was transferred to a special class for children with learning problems. Three months later he was again referred to us because of acute epigastric pain. The only abnormal laboratory finding was a slightly elevated level of alanine aminotransferase. Although the symptoms disappeared in a few days, the transaminase levels remained above normal for the next 6 months. Further diagnostic work-up revealed low serum ceruloplasmin concentration and high 24-h urinary copper excretion. The hepatic copper concentration in liver biopsy was high (2900 microg/g dry weight), confirming the diagnosis of Wilson's disease. Brain MRI showed slight changes in white matter. The patient's asymptomatic sister was also diagnosed with Wilson's disease. Both siblings started penicillamine therapy and a copper-restricted diet. The copper content of the household water was found to be above average and a new plumbing system was installed. After 1 year from the initiation of the therapy, the transaminase concentrations normalized and both siblings were free of symptoms. After 2 years of therapy the patient was able to return to normal school. Wilson's disease must be borne in mind, when children are evaluated because of poor school performance, especially if they complain of abdominal symptoms.