Specifically, there were inverse associations of lower TYK2 expression in thyroid with reduced risk of hypothyroidism (OR, 0.86; 95% CI 0.75, 1.00), in skin with psoriasis and its related disorders (OR, 0.49; 95% CI 0.34, 0.69), psoriasis (OR, 0.47; 95% CI 0.33, 0.67), psoriasis vulgaris (OR, 0.53; 95% CI 0.36, 0.78), and psoriatic arthropathy (OR, 0.35; 95% CI 0.18, 0.68) (Fig. 2c). This evidence concerns the gene TYK2 and psoriatic arthritis.