[Vascular complications of homocystinuria: a retrospective multicenter study]. / Les manifestations vasculaires de l'homocystinurie: étude rétrospective multicentrique.

PURPOSE: Arterial or venous thromboses are frequent in patients with homocystinuria. Because severe homocystinuria is rare, prevalence of thrombosis, especially in France, is still unknown. METHODS: Review of the clinical outcome of 37 patients with homocystinuria due to cystathionine-cystathionine beta-synthase deficiency (34) and 5,10-methylenetetrahydrofolate reductase (three) lead us to describe vascular complications occurring in 12 (32%) of them. RESULTS: Venous thromboembolism is the earlier and the most frequent one and is mainly found in untreated late-diagnosed cases. Under specific treatment of homocystinuria, thromboses are rare and always a complication of surgery associated with high thromboembolic risk. Association with factor V Leiden increased the risk of venous thrombosis.

Is hyperprolinemia type I actually a benign trait? Report of a case with severe neurologic involvement and vigabatrin intolerance.

Hyperprolinemia type I is a deficiency of proline oxidase (McKusick 23950), leading to hyperprolinemia and iminoglycinuria, usually with renal involvement. Hyperprolinemia type I is considered a benign trait. We reported a case of hyperprolinemia type I with a severe neurologic disorder and without renal involvement. The patient had marked psychomotor delay and right hemiparesis. Epilepsy was characterized by status epilepticus or a cluster of seizures. Laboratory findings revealed elevated levels of proline in the serum, urine, and cerebrospinal fluid without delta1-pyrroline 5-carboxylate dehydrogenase in the plasma or urine. Fluorescence in situ hybridization excluded a chromosome 22q11 deletion. Vigabatrin inhibits ornithine transaminase. Thus, vigabatrin could lead to a depletion of the normal pool of pyrroline 5-carboxylate dehydrogenase and could aggravate the clinical condition of the child. In this study, vigabatrin was discontinued. In the following months, the patient had marked psychomotor improvement, without modification of the epilepsy. We suggest that vigabatrin should be avoided in hyperprolinemia type I.

Urinary excretion of free cysteine in critically ill neonates.

UNLABELLED: In preliminary observations, significant amounts of free cysteine, a neurotoxic amino acid, were noted in the urine of asphyxiated or septic-shocked neonates. The present study was conducted to determine whether free urinary cysteine was elevated in these critically ill neonates compared with a control group, and to assess the clinical significance of this generation. Free cysteine was measured in the urine of newborn infants with perinatal asphyxia (n = 16) or neonatal sepsis (n = 14) and the urine of a control group (n = 10) by ion-exchange chromatography. Relationships between cysteine levels and the clinical severity, sulfite supply and neurological outcome of the patients were then studied. Urinary cysteine was 27.6 (15-49) mmol mol(-1) creatinine for the patients but was not detectable in the control group. Cysteine levels were correlated with the severity of neonatal septic shock but not with the grade of perinatal asphyxia and did not have a specific influence on the neurological outcome of these patients. The correlation between cysteine level and the severity of neonatal septic shock was indirect and probably linked to higher sulfite administration in this population. CONCLUSION: The mean daily supply of sulfites is high in critically ill neonates, mainly originating from dopamine and generating significant amounts of cysteine. Although a worsening effect attributable to cysteine on the neurological outcome of the patients could not be demonstrated, the appropriateness of cryptic administration of sulfites by way of drug excipients is called into question.

Atypical refsum disease with pipecolic acidemia and abnormal catalase distribution.

We describe an 18-year-old patient with psychomotor retardation and abnormally short metatarsi and metacarpals but no other signs of classic Refsum disease. Molecular analysis of the phytanoyl-coenzyme A hydroxylase gene revealed a homozygous deletion causing a frameshift. Surprisingly, L-pipecolic acid was elevated in plasma, and microscopy of the liver showed a reduced number of peroxisomes per cell and a larger average peroxisome size. These abnormal peroxisomes lacked catalase as did peroxisomes in fibroblasts of this patient. Such generalized peroxisomal abnormalities are not present in classic Refsum disease.

A woman with five consecutive fetal deaths: case report and retrospective analysis of hyperhomocysteinemia prevalence in 100 consecutive women with recurrent miscarriages.

OBJECTIVE: To evaluate the medical relevance of hyperhomocysteinemia in women with primary recurrent miscarriages. DESIGN: Case report and retrospective cross-sectional study. SETTING: Hematology outpatient department of a university hospital. PATIENT(S): Case report concerning a woman with five consecutive fetal losses. One hundred consecutive women with primary recurrent unexplained miscarriages (study group) and matched healthy controls (control group) with no antecedent fetal loss. INTERVENTION(S): Venous blood sample collection in resting individuals. MAIN OUTCOME MEASURE(S): Plasma total homocysteine concentrations, plasma folate concentrations, and DNA analysis for the C677T mutation of the 5,10 methylene tetrahydrofolate reductase gene. Normal threshold homocysteine concentration was obtained from values found in the control group (95th percentile). RESULT(S): The case patient was hyperhomocysteinemic, was homozygous for the C677T mutation in the methylene tetrahydrofolate reductase gene, and had plasma folate deficiency. Folic acid and pyridoxine administration normalized the homocysteine concentration and favored a successful pregnancy. In the retrospective study, 12 of 100 patients were hyperhomocysteinemic. Twenty percent had the C677T methylene tetrahydrofolate reductase genotype and 15% had low plasma folate concentrations. The highest values of homocysteine concentration were found in patients with both the C677T genotype and folate deficiency. CONCLUSION(S): Hyperhomocysteinemia should be identified in women with recurrent miscarriages because therapeutic normalization might permit a normal birth.

Plasma homocysteine as a risk factor for vascular disease. The European Concerted Action Project.

CONTEXT: Elevated plasma homocysteine is a known risk factor for atherosclerotic vascular disease, but the strength of the relationship and the interaction of plasma homocysteine with other risk factors are unclear. OBJECTIVE: To establish the magnitude of the vascular disease risk associated with an increased plasma homocysteine level and to examine interaction effects between elevated plasma homocysteine level and conventional risk factors. DESIGN: Case-control study. SETTING: Nineteen centers in 9 European countries. PATIENTS: A total of 750 cases of atherosclerotic vascular disease (cardiac, cerebral, and peripheral) and 800 controls of both sexes younger than 60 years. MEASUREMENTS: Plasma total homocysteine was measured while subjects were fasting and after a standardized methionine-loading test, which involves the administration of 100 mg of methionine per kilogram and stresses the metabolic pathway responsible for the irreversible degradation of homocysteine. Plasma cobalamin, pyridoxal 5'-phosphate, red blood cell folate, serum cholesterol, smoking, and blood pressure were also measured. RESULTS: The relative risk for vascular disease in the top fifth compared with the bottom four fifths of the control fasting total homocysteine distribution was 2.2 (95% confidence interval, 1.6-2.9). Methionine loading identified an additional 27% of at-risk cases. A dose-response effect was noted between total homocysteine level and risk. The risk was similar to and independent of that of other risk factors, but interaction effects were noted between homocysteine and these risk factors; for both sexes combined, an increased fasting homocysteine level showed a more than multiplicative effect on risk in smokers and in hypertensive subjects. Red blood cell folate, cobalamin, and pyridoxal phosphate, all of which modulate homocysteine metabolism, were inversely related to total homocysteine levels. Compared with nonusers of vitamin supplements, the small number of subjects taking such vitamins appeared to have a substantially lower risk of vascular disease, a proportion of which was attributable to lower plasma homocysteine levels. CONCLUSIONS: An increased plasma total homocysteine level confers an independent risk of vascular disease similar to that of smoking or hyperlipidemia. It powerfully increases the risk associated with smoking and hypertension. It is time to undertake randomized controlled trials of the effect of vitamins that reduce plasma homocysteine levels on vascular disease risk.

Plasma amino acid concentrations in elderly patients with protein energy malnutrition.

OBJECTIVE: to compare amino acid concentrations in healthy and malnourished elderly patients. METHOD: plasma amino acid concentrations were examined in 24 men and women (80-100 years of age) with protein energy malnutrition (PEM) and compared with those of 44 healthy, similarly-aged controls. Plasma samples were determined by using cation exchange columns with ninhydrin detection in an high performance liquid chromatography system. RESULTS: essential amino acid and non-essential amino acid plasma concentrations were significantly decreased in PEM (0.01 < P < 0.0001). Branched-chain amino acids and urea cycle amino acid plasma concentrations fell significantly (P < 0.0001). Plasma concentrations of alanine and glutamic acid + glutamine were also significantly reduced (P < 0.0001). CONCLUSIONS: in underweight elderly patients, the plasma amino acid pattern reflects the severity of the metabolic disturbance.

Treatment with vigabatrin may mimic alpha-aminoadipic aciduria.

PURPOSE: We describe a secondary effect of treatment with vigabatrin (VGB). A significant increase in alpha-aminoadipic acid (AAA) occurred in plasma and urine of VGB-treated children, thus mimicking a known rare metabolic disease, alpha-aminoadipic aciduria (AAAuria). METHODS: We studied eight children, aged from 3 months to 5 years, who were receiving VGB for drug-resistant partial epilepsies. Plasma and urine amino acids were assayed with ninhydrin detection on an automated Beckman 6300 analyzer. RESULTS: In eight out of eight children, there was a significant increase of AAA in plasma and in urine. Plasma values ranged from 7 to 8 microM (control values, < 5) and urinary values from 67 to 274 mmol/mol creatinine (control values, < 25). CONCLUSIONS: The concentrations of AAA in these VGB-treated children were as high as the concentrations found in the inherited metabolic disease, AAAuria. This could lead to incorrect diagnosis and to inappropriate genetic counseling. Thus whenever a genetic metabolic disease is suspected, amino acid chromatography testing should be performed before initiation of treatment with VGB.

Congenital non-progressive encephalopathy and deafness with intermittent episodes of coma and hyperkynureninuria.

Six of nine children born from first-cousin parents presented with the same clinical picture: non-progressive congenital encephalopathy with marked hypertonia resembling the stiff-baby syndrome, delayed milestones, mental deficiency and congenital deafness. Rare, usually reversible, episodes of sudden worsening of the neurological status, with progressive loss of consciousness and increase of hypertonia, occurred spontaneously or during febrile illnesses. During these periods, and sometimes on other occasions, transitory renal dysfunction was observed (nephrotic syndrome and/or tubular abnormalities). Death occurred before age 2 years in 4 patients; 2 are still alive (10 and 13 years old). Electrophysiological, biological and enzymatic investigations remained negative, particularly those concerning mitochondrial and peroxisomal metabolism. The only biochemical anomaly was a massive hyperkynureninuria, seen only during the periods of coma (up to 213 mumol/mmol creatinine; normal < 10) and after an intravenous protein loading test. This suggests an anomaly of tryptophan metabolism which has not been reported up to now.

Major hyperpipecolataemia in a normal adult.

We describe the fortuitous discovery of a 44-year-old man with a very high hyperpipecolataemia (250 mumol/L; normal < 2.5). This patient has none of the clinical features seen in peroxisomal diseases, he is a strictly normal intelligent adult. A stereochemical study of this pipecolic acid was performed using D-amino acid oxidase, and identified it as L-pipecolic acid. We suggest that isolated L-hyperpipecolataemia may be a benign trait.