A patient with an apparently sporadic pheochromocytoma with a rearranged during transfection codon 635 variant: a mild form of multiple endocrine neoplasia type 2?
OBJECTIVE
Multiple endocrine neoplasia 2 (MEN2) is an autosomal dominant disorder characterized by medullary thyroid carcinoma (MTC), pheochromocytoma, and hyperparathyroidism, with mutations at codon 634 in exon 11 of the RET (REarranged during Transfection) proto-oncogene identified as the most common genetic defect.


METHODS
We present a patient diagnosed with a left adrenal pheochromocytoma at a young age in whom we identified a mutation at codon 635 of the RET gene. No MTC has been clinically detected during a 6-year follow-up.


RESULTS
The C-to-T point mutation at nucleotide c.1903 results in an additional cysteine in the cysteine-rich domain due to the replacement of arginine with cysteine. One of the patient's 2 children has the same sequence variant in the RET proto-oncogene and has remained unaffected during follow-up.


CONCLUSIONS
The majority of mutations in this disorder affect cysteine residues in the cysteine-rich region of the extracellular domain of the RET protein, disrupting normal cysteine pairing. Consequently, we consider that this variant is likely of pathogenic significance, but this has not been unequivocally confirmed.
Department of Endocrinology, University Hospital Complex, Albacete, Spain.
Isabel
I
Huguet
Department of Endocrinology and Molecular Genetics, University of Oxford, Oxford, United Kingdom.
Treena
T
Cranston
Clinical Genetics, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, United Kingdom.
Lisa
L
Walker
Department of Endocrinology and Molecular Genetics, University of Oxford, Oxford, United Kingdom.
Niki
N
Karavitaki
Department of Endocrinology and Molecular Genetics, University of Oxford, Oxford, United Kingdom.
Ashley B
AB
Grossman