Genetic characterisation of a cohort of children clinically labelled as GH or IGF1 insensitive: diagnostic value of serum IGF1 and height at presentation

作者:Storr Helen L*; Dunkel Leo; Kowalczyk Julia; Savage Martin O; Metherell Louise A
来源:European Journal of Endocrinology, 2015, 172(2): 151-161.
DOI:10.1530/EJE-14-0541

摘要

Objective and design: GH insensitivity (GHI) encompasses growth failure, low serum IGF1 and normal/elevated serum GH. By contrast, IGF1 insensitivity results in pre-and postnatal growth failure associated with relatively high IGF1 levels. From 2008 to 2013, 72 patients from 68 families (45M), mean age 7.1 years (0.4-17.0) with short stature (mean height SDS -3.9; range -9.4 to -1.5), were referred for sequencing. Methods: As a genetics referral centre, we have sequenced appropriate candidate genes (GHR, including its pseudoexon (6 Psi), STAT5B, IGFALS, IGF1, IGF1R, OBSL1, CUL7 and CCDC8) in subjects referred with suspected GHI (n=69) or IGF1 insensitivity (n=3). Results: Mean serum IGF1 SDS was -2.7 (range -0.9 to -8.2) in GHI patients and 2.0, 3.7 and 4.4 in patients with suspected IGF1 insensitivity. Out of 69 GHI patients, 16 (23%) (19% families) had mutations in GH-IGF1 axis genes: homozygous GHR (n=13; 6 6 Psi, two novel IVS5ds+1 G to A) and homozygous IGFALS (n=3; one novel c. 1291delT). In the GHI groups, two homozygous OBSL1 mutations were also identified (height SDS -4.9 and -5.7) and two patients had hypomethylation in imprinting control region 1 in 11p15 or mUPD7 consistent with Silver-Russell syndrome (SRS) (height SDS -3.7 and -4.3). A novel heterozygous IGF1R (c. 112G>A) mutation was identified in one out of three (33%) IGF1-insensitive subjects. Conclusion: Genotyping contributed to the diagnosis of children with suspected GHI and IGF1 insensitivity, particularly in the GHI subjects with low serum IGF1 SDS (<-2.0) and height SDS (<-2.5). Diagnoses with similar phenotypes included SRS and 3-M syndrome. In 71% patients, no diagnosis was defined justifying further genetic investigation.

  • 出版日期2015-2