Homocysteine levels - Before and after methionine loading - In 51 Dutch families

Martin den Heijer, Sietze Graafsma, Soon Young Lee, Bart van Landeghem, Leo Kluijtmans, Petra Verhoef, Terri H. Beaty, Henk Blom

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Elevated levels of homocysteine are a risk factor for vascular disease, thrombosis, neural tube defects and dementia. The 677C > T polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene appears to be the most important single determinant of plasma homocysteine concentration. In the current study, we estimated heritability and fit a series of models of inheritance for both fasting and postmethionine-load homocysteine levels in the HOFAM-study (HOmocysteine in FAMilies study), which included 306 participants from 51 pedigrees, ascertained through a hyperhomocysteinemic proband. The crude heritability was 21.6% for fasting and 67.5% for postloading homocysteine. After adjustment for MTHFR 677C > T genotype, heritability dropped to 5.2 and 63.9%, respectively. Segregation analysis revealed that a nongenetic model with equal transmission was the best fitting and most parsimonious model for fasting homocysteine levels, while a two-distribution, Mendelian model with residual familial correlation was best for postmethionine-load homocysteine levels. This study shows that postload homocysteine levels have a stronger genetic determination than do fasting homocysteine levels. The heritability of postload homocysteine levels were not strongly affected by adjustment for MTHFR 677C > T genotype, in contrast to fasting homocysteine levels. Further studies are needed to identify the genes responsible for the inheritance of postload homocysteine levels.

Original languageEnglish (US)
Pages (from-to)753-762
Number of pages10
JournalEuropean Journal of Human Genetics
Issue number6
StatePublished - Jun 2005


  • B-vitamins
  • Heritability
  • Homocysteine
  • Methionine loading test
  • Segregation analysis

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)


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