Objective: To describe two cases of familial hyperparathyroidism with genetic analysis and report a new gene mutation.
Methods: Clinical and laboratory details of a brother and sister with hyperparathyroidism and nephrolithiasis are presented. The family history is reviewed, and results of direct sequencing analysis for mutations in the MEN1 gene are discussed.
Results: Isolated familial hyperparathyroidism is uncommon. Whether this condition is a partial expression of multiple endocrine neoplasia type I, a well-known genetic disorder, or an independent entity is being debated and studied. Two cases of hyperparathyroidism were diagnosed in a brother and a sister from a family that has expressed isolated hyperparathyroidism in several family members as the only manifestation thus far. A novel genetic mutation involving a CGG to CGT alteration in codon 219 of the MEN1 gene was discovered; to our knowledge, this particular variation has not been reported previously.
Conclusion: In patients with isolated familial hyperparathyroidism, a search for a mutation in the MEN1 gene may eventually help clarify this uncommon familial condition.