LAUSR

Abstract Objective 3-M syndrome is characterized by severe short stature, syndromic features, and characteristic radiographic findings. Growth hormone (GH) has been used with variable success. Recombinant human insulin like growth factor-1 (rhIGF-1) has never been utilized. Case presentation We describe a child with severe growth retardation, macrocephaly, and skeletal abnormalities with evidence of GH insensitivity subsequently treated with rhIGF-1. He developed morbid obesity and comorbidities including voracious appetite, acanthosis nigricans, tonsillar hypertrophy, and severe obstructive sleep apnea with minimal height improvement. Genetic testing done at 11.5 years revealed a compound heterozygous mutation (c.2112G>A(p.W704X) and c.2559delC) in the CUL7 gene consistent with 3-M syndrome-1. rhIGF-1 therapy was discontinued. Conclusions This case highlights the novel use of rhIGF-1 therapy on a child with 3-M syndrome-1 with minimal height benefit but accelerated weight gain and serves as a reminder of the importance of re-evaluating therapy efficacy and side effect profile.