Familial isolated parathyroid adenoma in a consanguineous family

The 23-year-old Caucasian male propositus presented with symptomatic hyperc alcemia, hypophosphatemia and normocalciuria for 2 months. His 29-year-old brother had under-gone an operation for recurrent parathyroid adenoma at ag e 26 and 28. No other member of the family was affected. His father and mot her were second-degree relatives. Laboratory studies showed primary hyperpa rathyroidism (pHPT), while the remaining endocrine studies and genetic test ing for multiple endocrine neoplasia 1 and 2A were normal. Technetium-cardi olite scintigraphy and ultrasound scans revealed a parathyroid mass at the left lower neck. Apart from bilateral hearing loss due to gentamicin treatm ent as a pre-term child, the patient was in of good health. Signs or sympto ms of other endocrinopathies were absent. The patient was referred for para thyroidectomy with subsequent autotransplantation of the remaining glands i nto his sternocleidomastoid muscle. Histological examination revealed an ad enoma with oncocytic differentiation, similar to that seen in his brother. The disease may follow a recessive mode of inheritance or may be due to a d ominant germ-cell mutation in one of the parents. The presented case may ul timately help in elucidating the molecular genetic basis of this rare form of pHPT.