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A quantitative trait locus (QTL) on chromosome 6q influences birth weight in two independent family studies

Rector Arya1, Ellen Demerath, Christopher P Jenkinson

  • 1Division of Clinical Epidemiology, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, 78229-3900, USA. arya@uthscsa.edu

Human Molecular Genetics
|April 14, 2006
PubMed

Insights

Researchers identified a major gene influencing birth weight on chromosome 6q. This finding, significant for understanding infant health and later-life diseases, was replicated across Mexican- and European-American populations.

Area of Science:

  • Genetics
  • Human Development
  • Complex Disease Etiology

Background:

  • Low birth weight (LBW) is a significant global contributor to infant mortality and morbidity.
  • LBW is inversely correlated with adult complex diseases, including obesity, type-2 diabetes, and cardiovascular disease.
  • Genetic factors influencing birth weight and its long-term health associations remain largely uncharacterized.

Purpose of the Study:

  • To conduct a genome-wide search for genes influencing birth weight variation.
  • To investigate the genetic basis of birth weight in Mexican-American and European-American populations.
  • To identify genetic loci associated with fetal growth and development.

Main Methods:

  • Genome-wide search utilizing data from the San Antonio Family Birth Weight Study (n=840).
  • Estimation of birth weight heritability adjusted for sex and term.
  • Multipoint linkage analysis to identify chromosomal regions linked to birth weight variation.
  • Replication analysis in an independent European-American cohort.

Main Results:

  • Heritability of birth weight was estimated at 72.0+/-8.4% (P<0.0001).
  • Strongest evidence for linkage (LOD=3.7) was identified on chromosome 6q between markers D6S1053 and D6S1031, replicated with LOD=2.3 in a European-American population, yielding an adjusted LOD of 4.3.
  • Potential candidate genes in the 6q region include chorionic gonadotropin, alpha chain; collagen, type XIX, alpha-1; and protein-tyrosine phosphatase, type 4A, 1.
  • Additional suggestive linkage evidence (LODs 1.3-2.7) was found on chromosomes 1q, 2q, 3q, 4q, 9p, 19p, and 19q.

Conclusions:

  • Substantial evidence supports a major locus on chromosome 6q influencing birth weight variation.
  • This locus plays a role in fetal growth and development.
  • The identified genetic influence on birth weight is consistent across both Mexican- and European-American populations, highlighting its broad relevance.

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