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Table 1 Characteristics of medullary thyroid carcinoma (MTC) in phenotypic variants of MEN 2 syndrome

Multiple endocrine neoplasia type 2A (MEN 2A) (Sipple syndrome)

Multiple endocrine neoplasia type 2B (MEN 2B) (mucosal neuroma syndrome or Wagenmann-Froboese syndrome)

Familial MTC

Multiple endocrine neoplasia type 2A (MEN 2A) (Sipple syndrome)

Multiple endocrine neoplasia type 2B (MEN 2B) (mucosal neuroma syndrome or Wagenmann-Froboese syndrome)

Familial MTC

Proportion of hereditary MTC cases in MEN2 syndrome by phenotype

60-90%

5%

5-35%

Incidence of MTC and age of onset

Early childhood, most distinctive and aggressive variant

100%

Middle age, mildest variant

Risk for pheochromocytoma

50%. Highest frequency with mutations in codon 634 and 918

50% (often bilateral and multiple)

0%

Risk for parathyroid disease (multigland hyperplasia and adenoma)

20-30%. Highest frequency with codon 634 mutation

Uncommon

0%

Requirements for clinic diagnosis in suspected families

2 or more specific endocrine tumors

95% have affected parent and 5% will have de novo gene mutations

MTC associated with mucosal neuromas, distinctive facies with enlarge lips, Marfanoid habitus, GI ganglioneuromatosis 50% have affected parent (usually paternal) and 50% will have de novo gene mutations.[25]

Multiple MTC or RET mutation carriers over the age of 50

No pheochromocytoma or parathyroid disease

RET mutation analysis

95% in exon 10 or 11 (codon Cys634 in approximately 85% of families. Other identified mutations include Cys 609, 611, 618, 620)

95% single point mutation in exon 16 (codon Met918). A second mutation in exon 15 (codon Ala883 has also been identified)

85%, mostly mutation of cysteine codons 618, 620, 634. Other identified mutations include Cys 609, 611, 613, 790, 791, 844, and 891, Glu 768, and Val804

Timing for prophylactic thyroidectomy

Before age 5 years

Before age 5 years

Before age 1 year

Source: Adapted from Refs. [7,24],

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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