In fact, PTH levels seem to modulate the severity of disease in all affected family members: subject II.4 has very high levels of PTH (365–500 pg/ml) and is asymptomatic; subject II.2 presents high PTH levels (172–198 pg/ml) and a mild phenotype (late onset cataracts and memory complaints); subject II.1 has mostly normal PTH levels and a severe cognitive deterioration. Here, PTH is linked to cataract.