Ancient origin of the CTH alelle carrying the c.200C>T (p.T67I) variant in patients with cystathioninuria

Hereditary cystathioninuria is due to mutations in the CTH gene that encodes for cystathionase, a pyridoxal-5'-phosphate (PLP) dependent enzyme. To date, mutations in this gene have been described in 10 unrelated cystathioninuric patients. Enzyme assays have showed that mutated cystathionase exhibits lower activity than controls. As cystathioninuria is usually accompanied by a wide variety of symptoms, it has been questioned whether it is a disease or just a biochemical finding not associated with the clinical picture of these patients. This is the first report of Spanish patients with cystathioninuria and mild to severe neurological symptoms in childhood. After oral pyridoxine therapy biochemical parameters have normalized but clinical amelioration was not evident. All patients were homozygotes for the c.200C>T (p.T67I) variant which is the most prevalent inactivating mutation in the CTH gene. To further investigate the history of the alleles carrying the c.200C>T transition in Europe, we also constructed the haplotypes on the CTH locus in our Spanish patients as well as in a clinical series of cystathioninuric patients from the Czech Republic harboring the same nucleotide change. We suggest that the CTH p.T67I substitution could have an ancient common origin, which probably occurred in the Neolithic Era and spread throughout Europe.

Are plasma homocysteine and methionine elevated when binging and purging behavior complicates anorexia nervosa? Evidence against the transdiagnostic theory of eating disorders

OBJECTIVE

To determine whether plasma total homocysteine (tHcy) and plasma methionine levels are different in anorexia nervosa restricting type (AN-R) compared to anorexia nervosa binge eating/purging type (AN-BP).

METHODS

Cross-sectional design.

SUBJECTS

Subjects were recruited from the outpatient program of the Eating Disorders Program at St. Paul's Hospital, Vancouver, Canada. All subjects had a current Diagnostic and Statistical Manual of mental Disorders - Fourth Edition (DSM-IV) AN-R, or AN-BP diagnosis. Controls were recruited from staff and trainees of Child and Family Research Institute, and Children's and Women's Hospital, University of British Columbia.

RESULTS

Samples were obtained from AN-R (N=30), AN-BP (N=32) and control women (N=73) and men (N=33). The 5- 95th% confidence intervals from the control women were taken as the normal range. The plasma tHcy and methionine for the control group had a 5-95th percentile range of 5.66-10.57 and 15.3-40.2 microM, respectively. Plasma tHcy was elevated in women with AN-BP (9.24+/-0.85 microM, N=32) but not with AN-R (7.90+/-0.38 microM, N=30). Plasma methionine was decreased in women with AN-BP (22.2+/-1.43 microM, N=32) compared to the control group of women (25.1+/-0.89 microM). The plasma methionine/tHcy ratio was elevated in the women with AN-BP (0.50+/-0.09) but not in those with AN-R (0.34+/-0.03).

CONCLUSION

Elevated plasma tHcy and decreased plasma methionine are consistent with impaired homocysteine remethylation. Altered methyl transfer capacity or methyl deficiency could impair monoamine neurotransmitter metabolism potentially impacting cognitive and psychological function.We hypothesize that the treatment of AN-BP should consider the need for nutritional support of methyl metabolism.

Children with acute lymphoblastic leukaemia have high plasma levels of total homocysteine at time of diagnosis

OBJECTIVE

Cancer can induce venous thromboembolic complications for various reasons. As part of a greater study, acquired and congenital prothrombotic risk factors were investigated in children with leukaemia or non-Hodgkin's lymphoma and compared with similar investigations in children with congenital heart defects.

MATERIAL AND METHODS

Blood samples were taken from 60 children with newly diagnosed leukaemia or lymphoma and 133 children with congenital heart defects in the course of a scheduled cardiac catheterization. When children with cancer were in remission, analyses of acquired prothrombotic risk factors were repeated. Children with cancer were observed for symptoms of thromboembolism throughout their treatment period.

RESULTS

Total homocysteine levels were significantly raised in children with cancer (median value 10.0 micromol/L) as compared with the levels in children with congenital heart diseases (5.0 micromol/L) (p<0.001), while children with acute lymphoblastic leukaemia had the highest values. The median level of lipoprotein(a) was slightly increased in children with newly diagnosed leukaemia or lymphoma (105 mg/L versus 100 mg/L, p<0.001), and levels of coagulation inhibitors were higher (p<0.001). Total homocysteine levels normalized when children attained remission of cancer disease. Two children had symptoms of acute thrombosis.

CONCLUSIONS

Raised concentrations of total homocysteine were frequent in children with newly diagnosed cancer, but this normalized when the children were in remission. The clinical significance of our observations and the impact on venous thromboembolism have yet to be defined.

Plasma homocysteine levels in female patients with eating disorders

OBJECTIVE

To examine plasma homocysteine, vitamin B(12), and folate levels in females with restricting and bingeing/purging eating disorders (EDs).

METHOD

Adolescent and adult female patients were compared to appropriate control groups with regard to plasma homocysteine levels.

RESULTS

The plasma homocysteine level of the adult ED patients was higher than that of controls for all age groups examined. In adolescents, no significant difference was found comparing ED patients younger than 16 years of age to control data, whereas in the 16-20 year age group, the plasma homocysteine level was significantly higher among the ED group, regardless of the type of ED. Vitamin B(12) and folate levels were within normal limits in all ED groups.

CONCLUSION

Elevated plasma homocysteine levels were found in adult and older adolescent female ED patients (but not in younger adolescents) compared to controls. This finding is not related to deficiencies in vitamin B(12) or folate.

Homocysteine, folic acid and vitamin B12 in relation to pre- and postnatal health aspects

Studies linking hyperhomocysteinemia (HHCY) and B-vitamin deficiency to some health aspects in children have been accumulating. Low B-vitamin status inearly life, even as early as the time of conception, may endanger the potential for new life and may negatively influence the health of the offspring. Early abortion, pregnancy complications and poor pregnancy outcomes have been linked to elevated concentrations of total plasma homocysteine (tHcy) and low folate or vitamin B12. Maternal vitamin status predicts that of fetuses and neonates. Lactating women are likely to experience low micronutrient status, which might affect breast-milk composition and hence the nutritional status of their breast-fed infants. Elevated concentrations of methylmalonic acid (MMA) is common in infants (age <6 months), which may indicate a transient inadequate vitamin B12 status. Deficiency of B-vitamins might confer deleterious effects on the physical and mental health of the child, such as impaired growth, gross motor function, poor school performance and other adaptive skills. The importance of maintaining adequate B-vitamin status during periods of progressive growth and development should be emphasized because symptoms related to folate and vitamin B12 deficiency are difficult to detect. Serum levels of tHcy and MMA should be estimated in several target groups of children, pregnant and lactating women and those planning for pregnancy. Concentrations of tHcy and MMA are useful indicators of B-vitamin status in the pediatric laboratory. Using these functional markers may facilitate detecting sub-optimal B-vitamin status in children.

Physiological variation in plasma total homocysteine concentrations in rats

Hyperhomocysteinemia was initially related to cardiovascular diseases; but homocysteine (Hcy) metabolism disturbances have more recently associated with a wide range of pathophysiological conditions including age-related diseases, disrupted circadian rhythms and gynaecological disorders. Since in many cases we do not know to what extent animal models are physiologically similar to human ones, this study aimed to track spontaneous variations in rat plasma Hcy concentrations during different physiological processes such as life cycle, 24 hours and estrous cycle. Plasma total Hcy concentrations were accessed by HPLC. Plasma Hcy concentration varied with age and newborns had the lowest values (2.94 +/- 0.47 micromol/L). Rats aged 10 days presented concentration similar to 3 month old animals (6.87 +/- 0.67 and 8.29 +/- 1.55 micromol/L respectively). Values decreased to 6.42 +/- 1.65 micromol/L at 6 months and 4.87 +/- 0.81 micromol/L at 28 months. Concerning circadian variations in Hcy concentration cosinor analysis showed acrophase in young rats at 1:09 pm, but no plasma Hcy circadian variations in aged rats. Female rats showed changes in Hcy concentration during the estrous cycle with higher values during the diestrous I (10.61 +/- 1.81 micromol/L) compared with the estrous (8.47 +/- 1.86 micromol/L) and diestrous II (7.68 +/- 1.58 micromol/L) phases. In conclusion, plasma Hcy concentration varied spontaneously with ontogenic development and during the estrous cycle and presented a circadian rhythm variation in young rats.

A role for homocysteine increase in haemolysis of megaloblastic anaemias due to vitamin B12 and folate deficiency: results from an in vitro experience

Megaloblastic anaemias (MA) are frequently associated with haemolysis. The pathogenesis of these finding is not clear, but it is thought to depend on the greater destruction of abnormal and fragile megaloblastic erythrocytes. Vitamin B(12) and folate deficiencies are the commonest cause of MA; these deficiencies may simultaneously induce a significant alteration in homocysteine metabolism leading to hyperhomocysteinemia. Blood cells have enzymes involved in homocysteine metabolism. Considering the possible effects of hyperhomocysteinemia in erythrocyte toxicity (due to oxidative damage and/or to interaction with sulfhydryl residues of structural and enzymatic proteins), the aim of our study was to evaluate (1) the homocysteine blood cells production in patients with MA due to vitamin B(12) and folate deficiency and (2) the possible role and mechanism of hyperhomocysteinemia in MA haemolysis. After incubation at 37 degrees C, blood samples from MA patients showed higher and significant levels of Hcy, LDH, lipid peroxidation parameters (MDA), and ghost protein-bound Hcy than controls. Haemolysis (%) was higher in MA patients than controls and was significantly correlated with Hcy accumulation in the medium, lipid peroxidation indices and ghost protein-bound Hcy. No significant (or significantly lower) alterations through time in considered parameters were observed in the corresponding samples incubated at 4 degrees C or in samples incubated with methionine-free medium (lower Hcy production). Our data, deriving from an in vitro experience, suggest a possible role of Hcy accumulation due to vitamin B(12) and folate deficiencies in haemolysis associated to MA due to vitamin deficiency.

New atherosclerosis risk factors in obese, hypertensive and diabetic children and adolescents

In the last few years it has been proved that risk factors for atherosclerosis are present in children and adolescents, and that already at this early age they are connected with anatomic, atheromatous changes in vessels. These changes can not be fully explained as occurring in young people exhibiting traditional risk factors for the disease. The aim of the study was to evaluate levels of several new atherosclerosis risk factors (lipoprotein (a) (Lp(a)), apolipoprotein A-I (Apo A-I), apolipoprotein B (Apo B), homocysteine (Hcy), fibrinogen (FB), tissue plasminogen activator (t-PA) and tissue plasminogen activator inhibitor type 1 (PAI-1)) in children and adolescents with traditional risk factors (obesity, hypertension, diabetes).

MATERIALS AND METHODS

The study group consisted of 285 children and adolescents aged 14.3 years. Children were divided according to their main disease into groups: group A, children with obesity (n=49); group B, children with obesity and coexisting hypertension (n=56); group C, children with hypertension (n=58) and group D, children with diabetes (n=122). Control group consisted of 79 healthy children and adolescents aged 14.1 years. Lp(a), Apo A-I and Apo B levels were estimated by use of immunoturbidimetric methods; total Hcy, FB, t-PA and PAI-1 were estimated by use of immunoenzymatic methods.

RESULTS

Lp(a) level in the total study group was 30 mg/dl and was over twice higher than in control group, 14 mg/dl. Apo A-I level was significantly lower in group A (127.6 mg/dl) and in group B (125.8 mg/dl) versus 135.6 mg/dl in controls. The level of Apo B was significantly higher in total study group (86.2 mg/dl) and in groups A, B and D versus 73.5 mg/dl in controls. Hcy was higher in group B (8 micromol/l) and in group C (9.4 micromol/l) versus 6.2 micromol/l in the control group. The FB level was higher in the total study group (276.7 mg/dl) and in groups A (318.8 mg/dl) and B (322.6 mg/dl) versus 252.8 mg/dl in controls. Significantly higher t-PA level was found in groups A (9 ng/ml) and B (9.7 ng/ml) versus 7.3 ng/ml in controls, and PAI-1 level was significantly higher in the total study group (62.3 ng/ml) and in groups A (73.8 ng/ml), B (78 ng/ml) and C (73 ng/ml) versus 42.4 ng/ml in the control group. Correlation analysis showed significant relationship between body mass index (BMI) and Apo B, Hcy, FB, t-PA and PAI-1. Blood pressure values correlated positively with Hcy. Correlations were verified in multiple regression analysis models: FB and t-PA levels depended on BMI, and Hcy depended on systolic blood pressure.

CONCLUSIONS

(1) Young obese, hypertensive and diabetic patients present significant disturbances in lipid metabolism, regarding mainly total cholesterol, LDL, triglycerides, as well as Lp(a), Apo A-I and Apo B levels. Unfavourable lipid profile is characteristic mainly for children with obesity and accompanying hypertension. (2) Elevated Hcy levels are found in children with hypertension. (3) Elevated FB level and diminished fibrinolytic activity are characteristic of obese children.

Reduced total plasma homocyst(e)ine in children and adolescents with type 1 diabetes

OBJECTIVES

The objective was to investigate total plasma homocyst(e)ine (tHcy), methylenetetrahydrofolate reductase (MTHFR) genotype, and the contribution of diet to homocysteine values in children and adolescents with type 1 diabetes and a control group.

STUDY DESIGN

A total of 78 children with type 1 diabetes and 59 members of an age- and sex-matched control group were recruited. Fasting samples were collected for tHcy, MTHFR genotype, serum vitamin B(12), serum folate, red cell folate, and plasma creatinine. Food frequency questionnaires targeted intake of folate, vitamin B(6), and vitamin B(12).

RESULTS

Fasting tHcy was reduced in patients compared with the control group (4.7 vs 5.9 micromol/L, P <.001). Serum folate (P =.002), red cell folate(P <.001), and serum vitamin B(12) (P =.005) were higher, and plasma creatinine was lower. A significant difference in tHcy values between patients and the control group persisted after correction was done for these factors (r = 0.1, P =.02). No difference was seen in the frequency of MTHFR polymorphisms. tHcy was not elevated in those patients with the 677TT or 677T/1298C genotypes, although red cell folate was significantly higher in members of the case (P =.01) and control groups (P =.05) with a 677 TT genotype. Dietary intake of folate correlated with serum folate (r = 0.4,P =.005).

CONCLUSION

tHcy values are lower in children and adolescents with type 1 diabetes. Higher serum levels of folic acid and vitamin B(12), reflecting differences in dietary intake between children with diabetes and members of a control group, partially account for this difference.

A new HPLC micromethod to measure total plasma homocysteine in newborn

Total plasma homocysteine (tHcy) in children may be an useful biochemical marker for genetic risk of premature cardiovascular disease. We reported a rapid, isocratic HPLC method able to process very small amount of newborn plasma samples. A blood sample from heel capillary circulation was collected, using a heparinized capillary glass tube. Plasma sample from 1 to 10 microl was derivatized with ammonium-7-fluorobenzo-2-oxa-1,3-diazole-4-sulphonate after reduction with tri-n-butylphosphine and analyzed on Discovery C18 column, with a solution of acetonitrile-dihydrogenphosphate 0.1 M (8:92 v/v pH*2.1). This assay ensures a good recovery (95%), precision (CV 4.5%) and linearity (y=2.41x + 0.31, r=1). Due to its simplicity and reliability, our method is suitable for routine analysis of tHcy and other aminothiols (Cys, Cys-Gly, GSH) assessed for clinical and research purposes. With this HPLC method we have assayed tHcy levels in 1400 apparently healthy newborn babies (tHcy mean value=4.9+/-2.7 microM). In conclusion, this accurate and linear HPLC method allows measurement of tHcy in newborn during the routinary capillary blood collection in the fourth living day without any other invasive procedure.

Children with stroke: polymorphism of the MTHFR gene, mild hyperhomocysteinemia, and vitamin status

The aim of this study was to investigate a possible association among the thermolabile polymorphism, nucleotide 677 cytosine to thymidine point mutation (677 C-->T) of the methylenetetrahydrofolate reductase (MTHFR) gene, hyperhomocysteinemia, serum folate, vitamins B12 and B6, and stroke in children. Allele and genotype frequencies for the 677 C-->T polymorphism in 21 children with stroke and 28 healthy children of the same age were studied. No differences in allelic frequency were detected between the two populations. However, the prevalence of homozygous 677 C-->T was doubled in the stroke population (28.6%) compared to the healthy group (14.3%). Total plasma homocysteine (tHcy) levels were significantly increased in children aged 2 months to 15 years with stroke compared to reference values. No association was observed between the homozygous genotype (T/T) and hyperhomocysteinemia, nor between the T/T genotype and low folate levels (below the 95th percentile) in this group of patients. Vitamin concentrations in patients were not significantly different from reference values. Significant negative correlations were found between tHcy and folate and between tHcy and cobalamin, but not between tHcy and B6 concentrations. In summary, a higher prevalence of hyperhomocysteinemia and the 677 C-->T polymorphism were observed in children with stroke, but were not always associated. The systematic study of both abnormalities in children with stroke is recommended, so that hyperhomocysteinemia of any genetic origin can be corrected with vitamin supplementation. Moreover, the 677 C-->T genotype is a strong factor for predisposition to hyperhomocysteinemia and recurrent risk of stroke that might also be prevented with folate supplementation.

Hyperhomocysteinemia: a risk factor for ischemic stroke in children

BACKGROUND

Moderate hyperhomocysteinemia is a risk factor for arterial vascular disease and venous thrombosis in adults. We performed a case-control study to assess a possible relation between moderate hyperhomocysteinemia and ischemic stroke in Dutch children (age range, 0 to 18 years).

METHODS AND RESULTS

We measured plasma total homocysteine levels (tHcy) in 45 patients with ischemic stroke and in 234 controls. Hyperhomocysteinemia was defined as a tHcy above the 95th percentile regression line for the respective age of the controls. Hyperhomocysteinemia was present in 8 (18%) of the 45 patients with ischemic stroke. The odds ratio was 4.4 (95% CI, 1.7 to 11.6).

CONCLUSIONS

We conclude that moderate hyperhomocysteinemia is a risk factor for ischemic stroke in children.

Evaluation of hyperhomocysteinaemia in children with stroke

Hyperhomocysteinaemia is associated with an increased risk of arterial vascular disease and thrombosis in adults. Our aim was to study the association of hyperhomocysteinaemia and stroke in children. Since some patients who had suffered a stroke developed seizures and received treatment with anti-epileptic (antifolate) drugs, we also examined the possible interaction between anti-epileptic drugs and hyperhomocysteinaemia. Plasma total homocysteine was measured in 68 children with stroke (23 of the 68 were taking anti-epileptic drugs) and 100 children undergoing anti-epileptic treatment but without history of stroke, and we compared the values with our reference values for similar ages (n = 195). Total homocysteine was determined by high profile liquid chromatography with fluorescence detection. Hyperhomocysteinaemia was defined as a homocysteine concentration above the 95th percentile for the reference values. Significant differences were found in total homocysteine values of children with stroke and those taking anti-epileptic drugs compared with our reference values for similar ages, except for the adolescent group. Total homocysteine values above the 95th percentile for the reference values were found in 36% of patients with stroke and 28% of children on anti-epileptic treatment. Total homocysteine concentrations in the 23 patients with both stroke and anti-epileptic drug treatment were similar to those of untreated patients with stroke in all age groups. In summary, systematic screening for hyperhomocysteinaemia should be included in the protocol to investigate the aetiology of stroke, even in paediatrics. Anti-epileptic treatment in children with stroke may be responsible for the mild hyperhomocysteinaemia observed in some of them. A dietary supplement of folate may be of benefit in children with stroke and in patients taking anti-epileptic drugs.