In a previous paper (Burri et al., 1990), we have shown that experimental hyperphenylalaninemia (hyper-Phe) in 3-17 d-old rats leads to reduced myelinogenesis. Such treated rats recover during a 6 w low phenylalanine (Phe) period between days 17 and 59. In order to get more detailed information about the disturbed myelinogenesis and recovery, we measured in hyper-Phe rats the developmental pattern of two brain enzymes typical for myelination, cerebroside sulfotransferase (CST), and 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP), and other developmental parameters. Further, we correlated brain Phe levels with the brain damage in hyper-Phe rats, and we measured brain acetylcholinesterase (AChE) as a neuronal marker. Experimental hyper-Phe rats, injected between postnatal days 3 and 17 with alpha-methylphenylalanine and phenylalanine, showed a delayed age-dependent increase of CST activity, compared to that of controls. In hyper-Phe rats, CST peak activity was reached 2-4 d later, and was lower than in controls. The age-dependent decrease of the CST activity, however, started in test and control rats at the same time, at day 21. Between days 24 and 59, hyper-Phe rats had normal CST activity. CNP activity in hyper-Phe rats was lower than in controls from day 10 to 35, and recovered to normal values between days 35 and 59. Our results indicate that recovery from reduced myelinogenesis is possible after the period of fast myelination without compensatory increased CST activity. Further, the brain damage in test rats with Phe levels higher than average is more severe than in test rats with Phe levels lower than average; and there is no effect of hyperphenylalaninemia on brain neurons containing AChE.

Acetylcholinesterase↗

PubMedDate not supplied

[3-hydroxy-3-methylglutaraturia. Clinical aspects, follow-up and therapy in a young child].

This is a report of an infant with 3-hydroxy-3-methylglutaryl-CoA-lyase deficiency. During infancy vomiting and feeding difficulties had been found repeatedly. Nutrition consisted in a mixture of one third of milk diluted with two thirds of water. Shortly before admission a change to whole milk had taken place. The one year old girl was admitted to the hospital because of vomiting and diarrhoea. Liver was enlarged and consciousness reduced. There was acidosis, hypoglycemia and an elevation of the transaminases. The typical pattern of organic acids in urine and dicarboxylic aciduria was pathognomonic. The diagnosis was proved by a deficiency of 3-hydroxy-3-methylglutaryl-CoA-lyase in fibroblasts. A protein and fat restricted diet, but also carnitine supplement was introduced. With the exception of severe hypoglycemia seizures on one morning the more than 2 1/2 year old girl is developed normally. It is of importance for future to avoid hypoglycemia after fasting, infections diseases or stress. The possible impairment of pancreatic function even in a normal clinical condition with normal values of transaminases is especially pointed out.

Amino Acid Metabolism, Inborn Errors↗

PubMedDate not supplied

[Carnitine deficiency and carnitine therapy in a patient with Rett syndrome].

BACKGROUND: Rett syndrome can be diagnosed only clinically. Several biochemical abnormalities are known, but none of them is characteristic. To our knowledge only one study on carnitine deficiency and one case of successful carnitine therapy have been reported. PATIENT: A five years old girl with normal milestones in the first months of life became retarded in the second year with muscle hypotonia of unknown cause and loss of known abilities. Later on recurrent washing movements of the hands, hyperventilation and microcephaly were observed and the diagnosis of Rett syndrome was established. METHOD: A muscle biopsy was performed for the determination of enzymes of the respiratory chain and polarographic respirometry in permeabilized muscle fibres at the age of 3 1/2 years. Carnitine in plasma and urine was determined before and during a therapy with carnitine. RESULTS: The activities of some enzymes of the respiratory chain were slightly decreased as was oxygen consumption in the permeabilized muscle fibres. However muscle morphology and histochemistry were normal. With normal carnitine in the muscle plasma carnitine was clearly decreased but showed a normal ratio of acylcarnitine to free carnitine. Carnitine substitution was started at the age of 3 1/2 years with 75 mg/kg/day and was later increased to 150 mg/kg/day. The treatment showed not only a normalisation of plasma carnitine but also an improvement of physical activity, muscle hypotonia, communication and sleep time. A wash out for one month and resumption of therapy confirmed the efficacy of this regime. CONCLUSIONS: The reason for the carnitine deficiency in the patient with Rett syndrome is not known. A primary carnitine deficiency is excluded by normal muscle carnitine. An explanation for the efficacy of the carnitine therapy is not known, although one could speculate that carnitine provides a transport system for acetyl groups, stimulates acetylcholine formation in the brain and in this way improves the disturbance of the cholinergic system.

Biopsy↗