At the age of 4 years, he experienced a generalized seizure associated with severe hypocalcemia (5.8 mg/dL, normal range 8.7–10.3 mg/dL) and high levels of serum carboxyl terminal fragments of PTH (C-PTH) (1.0 ng/mL, normal range < 0.5 ng/mL). The gene discussed is PTH; the disease is Hypocalcemia.