Objective: To clarify the contribution of the Asp905Tyr polymorphism of the muscle-specific 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/Try = 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.