SAT309 Clinical And Genetic Profiling Of Patients With Multiple Endocrine Neoplasia Type 2 Syndrome And Screening for Medullary Thyroid Carcinoma In Asymptomatic First-degree Relatives

Disclosure: K. Kumar P: None. Y. Gupta: None. A. Goyal: None. D. Kandasamy: None. N. Tandon: None. Background: Multiple endocrine neoplasia type 2 (MEN2) syndrome is a rare disorder with autosomal dominant inheritance, characterised by the presence of two of the following three endocrine manifestations: medullary thyroid carcinoma (MTC), pheochromocytoma (PCC) and primary hyperparathyroidism (PHPT) [1-2]. There is a paucity of data on clinical and genetic profile of MEN2 syndrome in the Indian subcontinent. Objectives: We aimed to evaluate the clinical and genetic profile of patients with MEN2 syndrome and perform screening for MTC among asymptomatic family members with serum calcitonin. Materials and Methods: This was an ambispective study conducted in the Department of Endocrinology at AIIMS New Delhi, involving diagnosed patients of MEN2 syndrome between January 2016 and December 2022. Results: We evaluated a total of 24 families with MEN2 syndrome comprising 61(MEN2A, n=56; MEN2B, n=5) patients, 18 patients were diagnosed as index cases. Data were derived retrospectively for 46 patients (MEN2A, n=43 MEN2B, n=3) and prospectively for 15 patients (MEN2A, n=13; MEN2B, n=2). The mean age at presentation of MEN2A and MEN2B were 28.6 ± 13.52 years and 22 ± 4.44 years, respectively. Of the study patients, 35 (57.38%) were females, among them 32 were MEN2A. Among 18 index patients 67% were synchronously detected to have MTC and PCC while 33% had MTC preceding PCC. Among patients with MEN2A syndrome 33 (59%) had MTC, 21(38%) had simultaneous PCC and MTC and one patient had PCC as presentation. We noted PHPT in 5 (9%) patients with MEN2A syndrome. Of the 5 patients with MEN2B syndrome, 4 (80%) presented with synchronous MTC and PCC and one (20%) presented with MTC aloneMetastatic MTC was noted in six patients with MEN2A syndrome and two patients with MEN2B syndrome. Median baseline Sr calcitonin level was 42 (4-1721) pg./ml in non-Metastatic group vs 3945(928-35572) pg./ml in distant metastasis group. 1 patient had metastasis from PCC to liver. Mutational analysis data are available for 40 patients. The most common mutations in MEN2A and MEN2B groups were C634R (exon 11 of RET gene, n=21) and M918T (exon 16 of RET gene, n=4), respectively.A total of 177 eligible family members of index patients with MEN2A syndrome were contacted, of whom 83 turned up for screening and 42 (50.6%) had elevated serum calcitonin levels (>10 pg./ml). Of the 26 eligible family members of index patients with MEN2B syndrome, only 9 could be screened and all had normal serum calcitonin levels (<10 pg./ml). Discussion & Conclusion: 1) This is the largest study comprising 61 patients after screening 24 family members in India. 2) Synchronous presentation of MEN2 with PCC and MTC is 67% vs 17% in western literature in Index patients. 3) MEN2 syndrome should be suspected in patients with MTC and young-onset PCC and all first-degree relatives of index patients with this syndrome. Presentation: Saturday, June 17, 2023