Screening for Serum Total Homocysteine in Newborn Children

Abstract

Results:The median (5th-95th percentile) tHcy concentration was 6.8 (4.2-12.8) mol/L. B 12 status, as determined by serum concentrations of B 12 , tHcy, and MMA, was moderately better in boys than in girls. tHcy concentrations between 10 and 20 mol/L were often associated with low B 12 , whereas tHcy >20 mol/L (n ‫؍‬ 43) was nearly always explained by increased methionine. tHcy did not differ according to folate concentrations or MTHFR 677C>T genotypes. None of the babies had definite CBS deficiencies, but heterozygosity led to low cystathionine, increased methionine, but normal tHcy concentrations.

Interactions between lifestyle and MTHFR polymorphisms on homocysteine concentrations in young adults belonging to the 1982 Pelotas Birth Cohort

“…22,23 There is a gradual increase of Hcy that begins from 10 years of age, continuing through puberty, and becoming higher in men than in women, but being less pronounced later in life. 3,24,25 Several studies have attributed this difference to sex hormones and fat-free mass. 22,26 However, in an elderly population from the Framingham Study, 27 the Hcy sex difference was explained by the intake of vitamins B 12 and B 6 , although this was not corroborated by the Hordaland Homocysteine Study.…”

The Headaches and Polymorphisms of the Methylenetetrahydrofolate Reductase

“…No association was found in Spanish and Portuguese migraineurs with TT genotype [10,12,13] Lorenz et al analyzed MTHFR 677TT polymorphism in a group of Estonian pediatric migraineurs and did not detect a close link with migraine prevalence [14] MTHFR C677T variant differently occur in different countries, so it could be considered an ethnic-specific polymorphism [14]. In the pathogenesis of aura migraine is hereby accepted the concept of "cortical spreading depression (CSD)", in the aura phase there is a cerebral oligoemia that starts to spread anteriorly and a condition of hyperemia follows to this [15,16].…”

“…The polymorphism C677T was identified using SAMPLE PREP thrombo kit (Diatech Pharmacogenetics), using a TAQman probe and a melting analysis to determinate genotypes [9]. The Total Homocysteine (tHcY) was determinated using a Chemiluminescent Immunoenzymatic Assay (CMIA) Homocysteine Architect [10].…”

“…In most of the genetic determination of C677T polymorphism studies carried out on whole blood samples using EDTA tubes and transferred in an upright position to local lab, where were stored at -20°C to freezer by the Real-Time Polymerase Chain Reaction (RT-PCR), and are considered the homozygous and heterozygous T alleles of variant [9]. The Total Homocysteine (tHcY) was determined using a Chemi-Luminescent Immunoenzymatic Assay (CMIA) Homocysteine Architect [10]. The data of Italy population show mutation in homozigous in 8, 8-10% of people [11,12].…”

Discrimination of Aliphatic Substrates by a Single Amino Acid Substitution inBacillus badiusandBacillus sphaericusPhenylalanine Dehydrogenases

“…9) In several countries, newborn screening for HCU is carried out using blood specimens as well as the diagnosis of phenylketonuria. 10) PheDH from Bacillus badius has been successfully used in the diagnosis of phenylketonuria in Japan for more than a decade. [11][12][13] We have screened for methionine dehydrogenase in nature with limited success, 14) but generation of a novel amino acid dehydrogenase with substrate specificity for L-Met might become available for a newborn screening program for HCU.…”