Short stature with brachydactyly caused by a novel mutation in the IHH gene and response to 4-year growth hormone therapy: a case report

Background: The etiology of short stature is heterogeneous. The disturbance of endochondral ossification and cartilage matrix synthesis caused by genetic mutations often causes short height combined with skeletal deformities in children. Some patients with minor skeletal abnormalities, such as short fingers and mild limb shortening, may be overlooked by clinicians and misdiagnosed as idiopathic short stature (ISS) or growth hormone deficiency (GHD). Case Description: We conducted a detailed investigation of laboratory and imaging examinations on a family with short stature and non-classical brachydactyly type A1 (BDA1) and summarized the clinical features. They received whole exome sequencing (WES) to reveal the possible genetic variation. A heterozygous mutation in the Indian hedgehog gene (IHH) (c.387_388insC, p.Thr130Hisfs*18) was found in the two siblings and their mother. The siblings both started recombinant human growth hormone (rhGH) therapy (rhGH: 33 lig/kg/day) and followed up for 4 years. After treatment, the siblings' height improved significantly, and they acquired a significant increase in the height standard deviation score (SDS) (the boy: +2.54, the girl: +1.86) during the 4-year therapy. No noticeable adverse effect was observed during rhGH treatment. Conclusions: We found a novel heterozygous pathogenic mutation in the IHH gene in a family and detailed the phenotype with short stature and non-classical BDA1. The therapy of rhGH showed promising effects. To avoid misdiagnosis, clinicians should not overlook minor skeletal anomalies in patients with short stature, especially those with a family history.