Introduction: Benign hereditary chorea (BHC) is a rare, autosomal dominant disorder, described as a non-progressive chorea of early onset. BHC can present as single neurologic disorder (13%), brain and thyroid disease (30%) or brainlungthyroid syndrome with congenital hypothyroidism and neonatal respiratory distress syndrome (50%).
Case Report: 18 months old infant was admitted to the Endocrinology Outpatient Clinic with motor delay and gait disorder. He was the second son of healthy and non-consanguineous parents. Family history was uneventful. Perinatal history was unremarkable for pulmonary problems and screening test for congenital hypothyroidism was normal. He presented short stature (2nd perc, −1.99 SDS), normal weight, without significant dysmorphic features. Neurological examination showed hypotonic and joint laxity, axial dystonia, and choreic movements. No inherited metabolic disease was shown, array-CGH were normal, and IGF1 levels were at the lower limit. TSH (8.46 μUI/ml) and fT4 (11.1 pg/ml) were consistent with a state of subclinical hypothyroidism. Brain MRI showed mild abnormalities in peripheral regions, with a large cistern and dysmorphism of the hippocampal formations. This clinical complex together with thyroid disorders led us to formulate the diagnostic suspicion of BHC and to analyse the thyroid transcription factor 1 gene (TITF1). This hypothesis was confirmed by molecular test with the detection of a heterozygous substitution (Pro291Arg) in the gene TITF1, cr.14q13.3.
Conclusion: The transcription factor 1 gene is essential for the organogenesis of the lungs and thyroid and in the development of the basal ganglia. The study of genotype/phenotype can be extremely complex in the presence of a highly variable disease expressivity. Mild alteration of TSH in presence of hypotonia, and choreic jerks has to take in account to suspect this rare condition. Our patient presented a de novo mutation and the choreic jerks were subtle and were not the dominant clinical feature.
18 Sep 2014 - 20 Sep 2014