Asp905Tyr Polymorphism of the Gene for the Skeletal Muscle-Specific Glycogen-Targeting Subunit of Protein Phosphatase 1 in NIDDM

OBJECTIVE To clarify the contribution of the Asp905Tyr polymorphism of the musclespecific glycogen-targeting subunit of protein phosphatase 1 (PP1G) to insulin resistance and related diseases. RESEARCH DESIGN AND METHODS We investigated the Asp905Tyr polymorphism of the PPP1R3 gene, which encodes the muscle-specific glycogen-targeting subunit of PP1G, in 259 Japanese patients with NIDDM and 194 healthy control subjects. RESULTS No significant difference was found in the genotype distribution between NIDDM patients (n = 259; Asp/Asp = 0.10, Asp/Tyr = 0.44, Tyr/Tyr = 0.46) and healthy control subjects (n = 194; Asp/Asp = 0.13, Asp/Tyr = 0.37, Tyr/Tyr = 0.50) or between patient groups subdivided by the mode of treatment: NIDDM patients with insulin therapy (Asp/Asp = 0.14, Asp/Tyr = 0.46, Tyr/Tyr = 0.40) and those without insulin therapy (Asp/Asp = 0.07, Asp/Tyr = 0.43, Tyr/Tyr = 0.50). However, NIDDM patients with the Tyr allele, which was previously reported to be associated with insulin resistance, tended to have lower BMIs than those without this allele (Asp/Asp: 24.5 ±1.1 kg/m2, Asp/Tyr: 22.6 ± 0.4 kg/m2, Tyr/Tyr: 22.8 + 0.3 kg/m2, P = 0.06 by analysis of variance). CONCLUSIONS These data suggest that the Asp905Tyr polymorphism of the PPP1R3 gene is not associated with NIDDM or high BMI, both of which are known to be insulin-resistant states, in the Japanese population.