Diabetes, Vol 41, Issue 7 843-849, Copyright © 1992 by American Diabetes Association
Glucokinase gene is genetic marker for NIDDM in American blacks
KC Chiu, MA Province and MA Permutt
Department of Internal Medicine, Washington University Medical School, St. Louis, Missouri 63110.
Glucokinase (ATP:D-glucose-6-phosphotransferase), expressed exclusively in
liver and pancreatic islet beta-cells, catalyzes the first step of
glycolysis and acts as glucose sensor and metabolic signal generator in
these tissues. The enzyme plays a key role in glucose homeostasis and as
such is an excellent candidate for inherited defects predisposing to
non-insulin-dependent diabetes mellitus (NIDDM). A compound-imperfect
dinucleotide (CA)n repeat element was found approximately 10-kb 3' of the
human glucokinase gene on chromosome 7p, which revealed polymorphism with
alleles differing in size by 2-15 nucleotides in unrelated individuals. A
polymerase chain reaction assay was developed, and genomic DNA from 275
biologically unrelated American black individuals was typed for glucokinase
alleles. The differences in allelic frequencies between individuals with
NIDDM and nondiabetic individuals were compared. After typing 112 diabetic
and 163 nondiabetic subjects, we found five different-sized alleles, with Z
defined as the most common allele, Z + 2, Z + 4, Z + 10, and Z - 15. The Z
allele was more common in nondiabetic subjects than in diabetic patients
(60.4 vs. 49.6%, P = 0.012). The Z + 4 allele was more common in diabetic
patients than in nondiabetic subjects (20.1 vs. 12.0%, P = 0.009). After
adjusting for age, sex, and body mass index, the Z + 4 allele continued to
have a positive association with NIDDM (P = 0.0018), and the Z allele had a
negative association with NIDDM (P = 0.0334). The Z + 4 allele, transmitted
as an autosomal dominant trait, appeared to be the most significant one at
this locus.(ABSTRACT TRUNCATED AT 250 WORDS)