Clinical use of molecular information in the management of multiple endocrine neoplasia type 2A.

One hundred and ninety-seven members of 28 kindreds with multiple endocrine neoplasia type 2A (MEN 2A) were screened for RET proto-oncogene exon 10 and 11 mutations. Seventy-one known affected individuals had mutations of codons 609, 618, 620 or 634, whereas 53 unaffected individuals had no abnormalities. Nineteen out of 54 individuals of unknown status, mostly children, had RET mutations. Four of these children had thyroidectomy based on this analysis and were found to have C-cell abnormalities. We identified one false negative mutation analysis because of a codon 691 polymorphism. We conclude that RET mutational analysis is a cost-effective and accurate method for determination of gene carrier status in MEN 2A.

Characterization of the clinical features of five families with hereditary primary cutaneous lichen amyloidosis and multiple endocrine neoplasia type 2.

The hereditary conditions of primary cutaneous lichen amyloidosis and multiple endocrine neoplasia type 2 (MEN 2) are rare clinical entities. The initial reports of two families in which the two conditions coincided have led to the identification of at least eight additional families with this clinical syndrome. In this report we describe the clinical features in five of these eight families. The salient feature in these five families is the presence of unilateral (46%) or bilateral (64%) pruritic and lichenoid skin lesions located over the upper portion of the back. Family members describe these skin lesions as intermittently intensely pruritic leading to scratching and excoriation of the upper back region. The presence of MEN 2 has been documented in 97% of family members with this skin lesion, the one exception being a child who is at risk for development of MEN 2A in whom the diagnosis has not yet been made. Of family members who have MEN 2A, 27% do not have an identifiable skin lesion, although the skin lesion developed in one patient two years after a curative thyroidectomy for medullary thyroid carcinoma (MTC). Four of the five families have members with pheochromocytoma; one with five affected members has only MTC. The finding of this clinical syndrome in geographically diverse portions of the world and the lack of overlap with MEN 2A without the skin lesion suggest it is a distinct clinical variant of MEN 2A.