This Article Full Text Full Text (PDF) All Versions of this Article: 93/9/3411    most recent Author Manuscript (PDF) Submit a related Letter to the Editor Purchase Article View Shopping Cart Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Google Scholar Articles by Mercado, M. Articles by Sosa, E. PubMed PubMed Citation Articles by Mercado, M. Articles by Sosa, E. Related Collections Neuroendocrinology and Pituitary Endocrine Oncology

Clinical and Biochemical Impact of the d3 Growth Hormone Receptor Genotype in Acromegaly

From the Endocrine Section and the Experimental Endocrinology Unit, Hospital de Especialidades, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, 11560 México City, Mexico

Address all correspondence and requests for reprints to: Moisés Mercado, Aristóteles 68, Polanco 11560, México City, México. E-mail: mmercadoa{at}yahoo.com or moises.mercado{at}imss.gob.mx.

Context: Lack of exon 3 of the GH receptor (d3-GHR) has been associated with increased responsiveness to GH therapy. By analogy, we hypothesized that patients with acromegaly bearing the d3-GHR genotype may have a more morbid clinical and biochemical picture.

Objective: Our objective was to determine whether the GHR genotype, by modifying tissue sensitivity to GH, influences the clinical/biochemical expression of acromegaly and its outcome after treatment.

Setting: The study was conducted at a specialized clinic at a tertiary care hospital.

Design, Patients, and Methods: We conducted a prospective genotype investigation and retrospective analysis and correlation with clinical, biochemical, and outcome data from a group of 148 patients. Samples from 175 healthy blood donors were used as controls. GHR genotyping was performed by real-time PCR.

Main Outcome Measures: We assessed prevalence of the three GHR genotypes (fl/fl, d3/d3, and d3/fl), associations between the genotypes, and baseline as well as post-therapeutic characteristics.

Results: Prevalence of the fl/fl, d3/d3, and d3/fl genotypes was 45, 22, and 32%, respectively, similar to what was found in the controls. Baseline characteristics were similar in carriers of the three genotypes. A positive correlation between IGF-I and log GH concentrations was significant only in homo- or heterozygous d3 carriers. Among d3-GHR carriers, diabetes, but no other comorbidities, was more prevalent (odds ratio = 2.02; 95% confidence interval = 0.96–4.2). d3-GHR carriers had significantly higher IGF-I concentrations after treatment. Multiple regression analysis revealed that the homo- or heterozygous lack of exon 3 was the strongest predictor of persistent biochemical activity (odds ratio = 1.29; 95% confidence interval = 0.65–2.58).

Conclusions: The absence of exon 3 of the GHR may be associated with a more morbid acromegalic clinical and biochemical picture and a lower chance of achieving IGF-I normalization after therapy.