title: Positive Association Between Type 2 Diabetes Risk Alleles Near CDKAL1 and Reduced Birthweight in Chinese Han Individuals.
abstract: BACKGROUND
  Fetal insulin hypothesis was proposed that the association between low birth weight and type 2 diabetes is principally genetically mediated. The aim of this study was to investigate whether common variants in genes CDKAL1, HHEX, ADCY5, SRR, PTPRD that predisposed to type 2 diabetes were also associated with reduced birthweight in Chinese Han population.
  
  
  METHODS
  Twelve single nucleotide polymorphisms (rs7756992/rs10946398 in CDKAL1, rs1111875 in HHEX, rs391300 in SRR, rs17584499 in PTPRD, rs1170806/rs9883204/rs4678017/rs9881942/rs7641344/rs6777397/rs6226243 in ADCY5) were genotyped in 1174 unrelated individuals born in Peking Union Medical College Hospital from 1921 to 1954 by TaqMan allelic discrimination assays, of which 645 had normal glucose tolerance, 181 had developed type 2 diabetes and 348 impaired glucose regulation. Associations of these 12 genetic variants with birthweight and glucose metabolism in later life were analyzed.
  
  
  RESULTS
  Birthweight was inversely associated with CDKAL1-rs10946398 (β = -41 g [95% confidence interval [CI]: -80, -3], P = 0.034), common variants both associated with increased risk of impaired glucose metabolism and decreased insulin secretion index later in life. After adjusting for sex, gestational weeks, parity and maternal age, the risk allele of CDKAL1-rs7756992 was associated with reduced birthweight (β = -36 g [95% CI: -72, -0.2], P = 0.048). The risk allele in SRR showed a trend toward a reduction of birthweight (P = 0.085).
  
  
  CONCLUSIONS
  This study identified the association between type 2 diabetes risk variants in CDKAL1 and birthweight in Chinese Han individuals, and the carrier of risk allele within SRR had the trend of reduced birthweight. This demonstrates that there is a clear overlap between the genetics of type 2 diabetes and fetal growth, which proposes that lower birth weight and type 2 diabetes may be two phenotypes of one genotype.
authors.forename: Xiao-Fang
authors.initials: XF
authors.lastname: Sun
authors.affiliation: Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Xin-Hua
authors.initials: XH
authors.lastname: Xiao
authors.forename: Zhen-Xin
authors.initials: ZX
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.forename: Tao
authors.initials: T
authors.lastname: Xu
authors.forename: Xi-Lin
authors.initials: XL
authors.lastname: Zhu
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xiao-Pan
authors.initials: XP
authors.lastname: Wu
authors.forename: Wen-Hui
authors.initials: WH
authors.lastname: Li
authors.forename: Hua-Bing
authors.initials: HB
authors.lastname: Zhang
authors.forename: Miao
authors.initials: M
authors.lastname: Yu
mesh_terms: D000262:Adenylyl Cyclases / Q000235:genetics; D000368:Aged; D000483:Alleles; D044466:Asian People / Q000235:genetics; D001724:Birth Weight / Q000235:genetics*; D051360:Cyclin-Dependent Kinase 5 / Q000235:genetics*; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics; D006801:Humans; D007230:Infant, Low Birth Weight; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2 / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D012359:tRNA Methyltransferases
chemical_list: C078492:HHEX protein, human; D018398:Homeodomain Proteins; D014157:Transcription Factors; D012359:tRNA Methyltransferases; D051360:Cyclin-Dependent Kinase 5; C525110:CDKAL1 protein, human; C090899:PTPRD protein, human; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2; D000262:Adenylyl Cyclases; C419510:adenylyl cyclase type V