A novel heterozygous STAT5B variant in a patient with resistant atopic dermatitis and short stature

Abstract

Introduction: Growth hormone (GH) exerts its effect through insulin-like growth factor 1 (IGF-I), an intracellular signalling molecule whose production is stimulated by STAT-5b after bind ing to the growth hormone receptor. STAT-5b deficiency, is char acterized by short stature, immune dysregulation and chronic lung disease. And these occur as a result of disruption of the growth hormone axis. Our case is an example of STAT-5b gene mutation, which is a rare disease and it has been defined for the last 10 years. Case: A 12-year-old male patient was admitted to our outpa tient clinic with complaints of short stature and skin rash. He was born 900 gr by cesarean section at 26th gestational week and had a 3-month neonatal intensive care hospitalization history. He was hospitalized with severe acute bronchiolitis attack twice, 1 year and 2.5 years old. He was followed up with diagnosis of atopic derma titis and hyperimmunoglobulin E for the last 3 years. In the family history; his mother’s and father’s height were 150 cm and 175 cm respectively, there was no consanguinity between mother andfather, and he had 2 healthy siblings. Anthropometric measure ments; his height, weight and body mass index were 134 cm (SDS: -1.9), 25.7 kg (SDS: -2.54), and 14.2 kg/m2 (SDS: -2.15) respec tively. The mid parental height SDS of the patient was -1.17. In his physical examination; he had erythematous eczematous lesions around the eyes, cheeks and chin, and xerosis on the hands, promi nent forehead and saddle nose. His testicular volumes were 4/4 ml and pubic hair was tanner stage 1. Laboratory examinations revealed low IGF level (98.7 ng/ml SDS: -1.67) and IGF binding protein 3 (IGFBP3) level (3.75 ng/L SDS: -3.56). Bone age was 8 years-old. GH stimulation tests with L-dopa revealed low basal GH levels and reduced GH response (peak GH of 2.24 ng/ml). Prolactin level was found to be 12.3ug/l. Height velocity was 6 cm per year. A new heterozygous STAT5b mutation (C.1906+1G>A) was detected.