ESPE Abstracts

Background: Congenital Hypothyroidism (CH) is the most common neonatal endocrinologic disorder and one of the most preventable causes of mental retardation and neurological alterations in children. The incidence of CH lies between 1 in 2000-3000 newborns. The replacement therapy with levothyroxine (LT4) should be started immediately since studies show that a rapid normalization of TSH and fT4 optimizes the neurodevelopmental outcome. Infants with Down syndrome have a higher risk of developing CH, moreover some congenital malformations, especially affecting the cardiovascular, urogenital, gastrointestinal, and musculoskeletal systems, seem to be mainly associated with CH.

Case presentation: We described a girl diagnosed with CH identified by neonatal screening. She presented an abnormal gland located in a position higher than usual. She started the replacement therapy on her 6th day of life with levotiroxine 9.5 µg/kg/die. She also had a congenital bilateral hydronephrosis and a mild congenital cardiopathy. During the follow up in her first months of life, she presented several serious infections, which required admission to the pediatric intensive care unit. Moreover, she has also been diagnosed a FPIES. We performed specific laboratory tests that permitted to rule out an immunological defect. When her health conditions improved, she had a rapid growth associated with a progressive psychomotor retardation. Considering all these features: CH, mild cardiopathy, congenital nephropathy, psychomotor delay and recurring infections we suspected a genetic cause for her condition. Genetic analysis evidenced a mutation of NSD1 gene (c.3439G>T p.(Glu1147*)) which permitted the diagnosis of Sotos Syndrome.

Conclusions: Only a previous clinical case describe an association between CH and Sotos syndrome in a patient with a different mutation of the gene NSD1. We confirm this relationship and hypothesize that this relationship is not random. Further studies are needed to better elucidate if CH is casual or a clinic feature of Sotos syndrome. We suggest to suspect a Sotos syndrome in patients with CH, cognitive delay and height acceleration.