Successful treatment of an invasive growth hormone-secreting pituitary macroadenoma in an 8-year-old boy

[Overgrowth with and without obesity: clinical and molecular principles]

Somatic overgrowth is a complex and heterogeneous pathology that is only partially understood, although developments in molecular biology have allowed the discovery of the aetiological basis of some of these conditions. The differential diagnosis of a patient with a possible variant of normality, a chromosomopathy, a dysmorphic syndrome, a metabolic or an endocrine disease is essential. The initial clinical evaluation should include a correct anamnesis and physical examination, as well as complementary laboratory and image analyses that will help to orient the diagnosis. This should include a full blood counts and complete biochemical analysis, determinations of IGF-I, IGFBP-3, free T4, TSH and homocystinuria, as well as a karyotype and an X-ray of the left hand and wrist. These results should be very beneficial in orienting the diagnosis. Additional molecular studies should be performed when a monogenic disease is suspected. Cardiological, ophthalmological, skeletal, psychological and psychiatric studies should be performed if the clinical information and previously mentioned complementary studies so indicate. In this review, the aetiological basis and the diagnostic-therapeutic principles in the most common causes of overgrowth, will be analysed.

An Intronic mutation is associated with prolactinoma in a young boy, decreased penetrance in his large family, and variable effects on MEN1 mRNA and protein

Prolactinomas are rare tumors in prepubertal children. A prolactinoma in a young child may be due to sequence variants in genes that are known to cause these tumors ( MEN1, PRKAR1A, AIP). An 11-year-old boy with a macroprolactinoma was treated with cabergoline and the tumor receded. We studied the patient and his family for genetic causes of this tumor. No mutations were present in the coding sequence of PRKAR1A and AIP. A novel heterozygous substitution (IVS3-7 c>a) was identified in intron 3 of MEN1. We also found an additional PCR amplicon that incorporated the entire intron 3 of the gene (210 bp) in the patient's cDNA. The same amplicon was present with lower intensity in some of the control individuals who were not mutation carriers. Intron 3 harbors an in-frame stop codon and its incorporation is predicted to result in a prematurely terminated protein. We conclude that a novel MEN1 variation was identified in a young boy with prolactinoma and six of his relatives who did not present with prolactinoma or other MEN1 related symptoms. This novel MEN1 variation may be associated with low penetrance of the disease. The IVS3-7 c>a defect is suggested to be pathogenic because it is associated with lower menin levels in the cells of these patients, but its consequences may be mitigated by a variety of factors including changes in transcription and translation of the MEN1 gene.