title: Heritability, parental transmission and environment correlation of pediatric-onset type 2 diabetes mellitus and metabolic syndrome-related traits.
abstract: OBJECTIVE
  To estimate the heritability, parental transmission and environmental contributions to the phenotypic variation in type 2 diabetes mellitus and metabolic syndrome-related traits in families of Mexican children and adolescents.
  
  
  METHODS
  We performed a cross-sectional study of 184 tri-generational pedigrees with a total of 1160 individuals (99 families with a type 2 diabetes mellitus proband before age 19). The family history of type 2 diabetes mellitus in three generations was obtained by interview. Demographic, anthropometric, biochemical and lifestyle information was corroborated in parents and offspring. We obtained correlations for metabolic traits between relative pairs, and variance component methods were used to determine the heritability and environmental components.
  
  
  RESULTS
  The heritability of early-onset of type 2 diabetes mellitus was 0.50 (p<1.0e-7). The heritability was greater than 0.5 for hypertension, hypoalphalipoproteinemia, hypercholesterolemia, body mass index, waist circumference, blood pressure, 2-h insulin, and cholesterol (p<0.001). In contrast, we observed a high environmental correlation (>0.50) for blood pressure, HbA1c and HDL-cholesterol after multivariate adjustment (p<0.05). Several traits, such as type 2 diabetes mellitus and insulin resistance, were significantly correlated only through the mother and others, such as hypertriglyceridemia, were significantly correlated only through the father.
  
  
  CONCLUSIONS
  This study demonstrates that type 2 diabetes mellitus and metabolic syndrome-related traits are highly heritable among Mexican children and adolescents. Furthermore, several cardiometabolic factors have strong heritability and/or high environmental contributions that highlight the complex architecture of these alterations.
authors.affiliation: Research Unit of Medicine Based on Evidence, Hospital Infantil de México Federico Gómez, Mexico City, Mexico.
authors.forename: América L
authors.initials: AL
authors.lastname: Miranda-Lora
authors.affiliation: Community Health Research Department, Hospital Infantil de México Federico Gómez, Mexico City, Mexico.
authors.forename: Jenny
authors.initials: J
authors.lastname: Vilchis-Gil
authors.affiliation: Department of Endocrinology, Hospital Infantil de México Federico Gómez, Mexico City, Mexico.
authors.forename: Mario
authors.initials: M
authors.lastname: Molina-Díaz
authors.affiliation: Community Health Research Department, Hospital Infantil de México Federico Gómez, Mexico City, Mexico.
authors.forename: Samuel
authors.initials: S
authors.lastname: Flores-Huerta
authors.affiliation: Community Health Research Department, Hospital Infantil de México Federico Gómez, Mexico City, Mexico; Research Committee, Latin American Society for Pediatric Gastroenterology, Hepatology and Nutrition (LASPGHAN), Mexico City, Mexico. Electronic address: klunderk@gmail.com.
authors.forename: Miguel
authors.initials: M
authors.lastname: Klünder-Klünder
mesh_terms: D000293:Adolescent; D000328:Adult; D000886:Anthropometry; D002648:Child; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000208:ethnology* / Q000209:etiology; D004777:Environment; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008019:Life Style; D008055:Lipids / Q000097:blood; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood / Q000208:ethnology* / Q000209:etiology; D017058:Mexican Americans; D010290:Parents; D010375:Pedigree; D010641:Phenotype; D012307:Risk Factors
chemical_list: D007328:Insulin; D008055:Lipids
keywords: Children; Heritability and environment; Metabolic syndrome; Type 2 diabetes mellitus