Screening a Large Pediatric Cohort with GH Deficiency for Mutations in Genes Regulating Pituitary Development and GH Secretion: Frequencies, Phenotypes and Growth Outcomes

Abstract

Background: Pituitary development and GH secretion are orchestrated by multiple genes including GH1, GHRHR, GLI2, HESX1, LHX3, LHX4, PROP1, POU1F1, and SOX3. We aimed to assess their mutation frequency and clinical relevance in children with severe GH deficiency (GHD). Methods:The Genetics and Neuroendocrinology of Short Stature International Study (GeNeSIS) was a prospective, open-label, observational research program for pediatric patients receiving GH treatment, conducted in 30 countries between 1999 and 2015. The study included a sub-study to investigate mutations in the genes listed above. PCR products from genomic blood cell DNA were analyzed by Sanger sequencing. DNA variants were classified as pathogenic according to the recommendations of the American College of Medical Genetics and Genomics. Demographic, auxologic, and endocrine data at baseline and during GH treatment were documented and related to the genotyping results. Findings: The analysis comprised 917 patients. In 92 patients (10%) 33 mutations were found, 16 previously described and 17 novel (52%). Mutation carriers were significantly younger, shorter, and more slowly growing than non-carriers. In general, their peak values in GH stimulation tests were very low; however, in 15/77 (20%) patients with GH1, PROP1, and SOX3 mutations they were only moderately diminished (3- 6µg/L). Two patients with a GH1 mutation developed TSH deficiency and one ADH deficiency. Using logistic multi-regression analysis, significant indicators of a mutation were combined pituitary hormone deficiency, greater patient-parent height difference (SDS), low GH peak, and young age. Final height SDS gain in mutation carriers (mean±SD 3.4±1.4) was greater than in non-carriers (2.0±1.4; P<0.001) and in patients with nonGHD short stature. Interpretation: DNA testing for mutations in children with severe GHD shows a positive finding in approximately 10%. Phenotypes of mutation carriers can be variable. The benefit for clinical practice justifies DNA testing as an important component in the diagnostic work-up of patients with severe GHD. Clinical Trial Number: (GeNeSIS; Clinical Trial Registry Number: NCT01088412) Funding Statement: Eli Lilly and Company, Indianapolis, IN, USA. Declaration of Interests: GeNeSIS was sponsored by Eli Lilly and Company (Lilly, Indianapolis, IN, USA). The sponsor funded all aspects of study design, data collection, genetic analyses and statistical analyses, but did not impose any impediment, directly or indirectly, on the publication of the study results. CJC and CJ are employees and stockholders of Lilly, while WFB, AGZ, and CAQ are former employees and stockholders of Lilly, GBC is a former employee of Lilly. WFB also reports he is a consultant for Ammonett Pharma, Lilly Germany and Merck KGaA Darmstadt. CLD, JL, RGR, JSP and RWP were members of the GeNeSIS International Scientific Advisory Board and received consulting and speaker fees from Lilly. The laboratories of SA and RWP received fees and grants from Lilly for setting up and conducting the genetic analyses. JK, HMP, ML. M-L S, and M-PL have no conflicting interests to report. Ethics Approval Statement: The study was conducted in accordance with the Declaration of Helsinki and approved by ethics review boards of the participating institutions. Written informed consent for data collection, data processing, DNA testing and publication was obtained from the parents or legal guardians, in accordance with national regulatory requirements.