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MUC7 Polymorphisms Are Associated With a Decreased Risk of a Diagnosis of Asthma in an African American Population
  1. Alan M. Watson, PhD*†,
  2. Wai-Man Ngor, BS*,
  3. Heather Gordish-Dressman, PhD*,
  4. Robert J. Freishtat, MD*‡¶,
  5. Mary C. Rose, PhD*§¶
  1. From the *Research Center for Genetic Medicine, Children's National Medical Center (CNMC); †Institute of Biomedical Sciences, School of Medicine and Health Sciences, George Washington University; ‡Division of Emergency Medicine, Children's National Medical Center (CNMC); and Departments of §Biochemistry and Molecular Biology, and ¶Pediatrics, School of Medicine and Health Sciences, George Washington University, Washington, DC.
  1. Received June 30, 2009, and in revised form August 10, 2009.
  2. Accepted for publication August 27, 2009.
  3. Reprints: Mary C. Rose, PhD, Research Center for Genetic Medicine, Children's National Medical Center, 111 Michigan Ave, NW, Washington, DC 20010. E-mail: mrose{at}
  4. Supported by grants from the Board of Visitors, Children's National Medical Center (BLV-08 to A.M.W.), and the National Institutes of Health (HL-33152 to M.C.R. and K23-RR-020069 to R.J.F.) and by a pilot grant from the DC-Baltimore Research Center on Child Health Disparities (P20-MD-000198 to R.J.F.).


Purpose Mucin glycoproteins contribute to lung pathophysiology in asthma. The protein backbone of mucin glycoproteins is encoded by specific MUC genes, which exhibit a high degree of polymorphisms that generate a variable number of tandem repeat (VNTR) domains. MUC7 typically encodes for 6 VNTRs, each with 23 amino acids. In a northern European cohort, a polymorphism encoding MUC7*5 (5-VNTR) is in 100% linkage disequilibrium with the single nucleotide polymorphism rs9982010 and associated with a decreased risk of being asthmatic and having better lung function. African Americans have a 5- to 10-fold increase in incidence of asthma relative to whites, who are believed to be partially associated with higher genetic susceptibility. Occurrence of the rs9982010 and MUC7 allelic frequencies was evaluated in inner-city African Americans to test their association with a diagnosis of asthma.

Methods Genomic DNA, collected from a cohort of African American asthmatic subjects, was used to detect the MUC7 VNTR polymorphisms and to analyze the rs9982010 single nucleotide polymorphism.

Results A logistic regression analysis showed that the MUC7*5-VNTR allele decreased the likelihood of a diagnosis of asthma (odds ratio, 0.173 [95% confidence interval, 0.041-0.737]; P < 0.018) and is not in a strong linkage disequilibrium with the rs9982010 (r 2 = 0.03; odds ratio, 66; confidence interval, 5.913-736.72). A novel MUC7*4-VNTR polymorphism, identified in an African American nonasthmatic individual, was linked to a structural rearrangement of the VNTR domain.

Conclusions These data extend the association of MUC7*5 allelic polymorphisms and asthma to inner-city African Americans.

Key Words
  • mucin genes
  • asthma
  • genetic polymorphism
  • African American
  • inner city

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