ABSTRACT
【Objective】 To investigate the clinical features and gene analysis of one pedigree with multiple endocrine neoplasia type 2A （MEN2A） so as to clarify the diagnosis and classification of the disease， guide treatment and prevention， and improve prognosis. 【Methods】 The clinical data of a 36-member MEN2A family， including 6 probands， with medullary thyroid carcinoma， were investigated， and the peripheral blood genomic DNA of 28 family members （blood sample of one proband was not collected） was extracted. PCR amplification was performed on exons 8， 10， 11， 13， 14， 15 and 16 of the RET gene， and the products were directly sequenced. 【Results】 Review of the medical history showed that two probands with medullary thyroid carcinoma were accompanied with hyperparathyroidism， and one family member had pheochromocytoma. The RET gene mutation test confirmed that 13 family members， consisting of 5 probands and 8 family members， had the RET proto-oncogene exon 10 missense mutation. The heterozygous missense had mutation c.1852T>A， leading to the conversion of cysteine （TGC） at position 618 to serine （AGC） （Cys618Ser）. All subjects carrying RET gene Cys618Ser mutation had abnormal thyroid ultrasound change， accompanied with elevated calcitonin levels. Subjects carrying wild type of RET gene had normal calcitonin levels. The family was finally diagnosed with MEN2A by RET gene detection. 【Conclusion】 RET gene detection plays key role in the diagnosis and treatment of patients with MEN2A family and has guiding value in the follow-up and prognosis of asymptomatic carriers. There is a positive correlation between calcitonin level and the RET protooncogene mutation Cys618Ser. Patients suspected of MEN2A should be screened in time.
ABSTRACT
Familial syndromes of hyperparathyroidism, including multiple endocrine neoplasia type 1 (MEN1), multiple endocrine neoplasia type 2A (MEN2A), and the hyperparathyroidism-jaw tumor (HPT-JT), comprise 2-5% of primary hyperparathyroidism cases. Familial syndromes of hyperparathyroidism are also associated with a range of endocrine and nonendocrine tumors, including potential malignancies. Complications of the associated neoplasms are the major causes of morbidities and mortalities in these familial syndromes, e.g., parathyroid carcinoma in HPT-JT syndrome; thymic, bronchial, and enteropancreatic neuroendocrine tumors in MEN1; and medullary thyroid cancer and pheochromocytoma in MEN2A. Because of the different underlying mechanisms of neoplasia, these familial tumors may have different characteristics compared with their sporadic counterparts. Large-scale clinical trials are frequently lacking due to the rarity of these diseases. With technological advances and the development of new medications, the natural history, diagnosis, and management of these syndromes are also evolving. In this article, we summarize the recent knowledge on endocrine neoplasms in three familial hyperparathyroidism syndromes, with an emphasis on disease characteristics, molecular pathogenesis, recent developments in biochemical and radiological evaluation, and expert opinions on surgical and medical therapies. Because these familial hyperparathyroidism syndromes are associated with a wide variety of tumors in different organs, this review is focused on those endocrine neoplasms with malignant potential.
