IMPE Abstracts

Introduction: The IHH gene (Indian hedgehog) is predominantly expressed in the developing skeleton. It encodes a protein produced by chondrocytes and involved in the IHH signaling pathway of paracrine cartilage growth factors (1). This protein, together with the PTHrP (parathyroid hormone-related protein) system, coordinates the proliferation and hypertrophy of chondrocytes (1). Inactivation of the IHH in humans causes numerous skeletal chondrodysplasias, including acrocapitofemoral dysplasia, type A1 brachydactyly, and human short stature. Skeletal chondrodysplasias caused by inactivating mutations of the IHH gene are among the most common forms of idiopathic short stature and are clinically characterized by varying degrees of short stature, short limbs, and brachydactyly (2). Currently, there is no effective treatment for these diseases. CASE REPORT: Patient, 5 years and 3 months old, male, born and resident in Fortaleza, sought medical care at the Walter Cantídio University Hospital (HUWC) on 03/24/22 due to a complaint of short stature. He was born at term (38 weeks), weighing 2900g (Z -0.44) and 46 cm (Z -1.48) and had a report of limb shortening on gestational ultrasounds. He evolved with disproportionate postnatal short stature with limb shortening. Report of short family stature with an average height of 150 cm among family members. Mother with 139.4 cm (upper segment/height ratio greater than 2 SD) and father with 151 cm (upper segment/height ratio greater than 2 SD), both with body disproportion. Target height 151.7 cm. They deny consanguinity. On physical examination, he was 99 cm tall (Z -2.72), weight 18.8 kg, BMI 19.2 (Z + 1.46), upper segment 59.5 cm; upper segment/height ratio 0.601 (greater than 2 SD), upper segment/lower segment 1.50 and brachydactyly. X-ray of hands and wrists showed shortening of the middle phalanges in the second and fifth fingers bilaterally. A molecular panel of skeletal dysplasias was carried out, which showed a variant of uncertain significance of the IHH gene (p.Met?) in the patient and in her father and the absence of variants that alone could justify the clinical picture in his mother. CONCLUSION: Disproportionate short stature associated with shortening of the middle phalanges may suggest the presence of heterozygous variants of the IHH gene, demonstrating that these, although rare, should be considered in the differential diagnosis of short stature.