Thyroid Functions in Children with Down’s Syndrome
Kevalee Unachak MD*, Pranoot Tanpaiboon MD*, Yupada Pongprot MD*, Rekwan Sittivangkul MD*, Suchaya Silvilairat MD*, Prapai Dejkhamron MD*, Jutamas Sudasna MD*
Affiliation : * Department of Pediatrics, Faculty of Medicine, Chiang Mai University, Chiang Mai
Objective : To evaluate thyroid function in children with Down’s syndrome, and to ascertain the presence of a
relationship between overt thyroid diseases and congenital anomalies.
Material and Method: One hundred and forty Down’s syndrome patients, aged from 3 days to 13 years 9
months, were evaluated for karyotype, thyroid functions and the coexistence of congenital anomalies.
Results : Trisomy 21 was found in the majority of cases (95.7%). Fifty-six patients (40%) had abnormal thyroid
functions: 53 (37.9%) hypothyroidism and 3 (2.1%) hyperthyroidism. Ten patients (7.1%) were diagnosed with
overt thyroid disease: congenital hypothyroidism 3.6%, acquired hypothyroidism associated autoimmune
thyroiditis 1.4% and hyperthyroidism 2.1%. None of the patients with congenital hypothyroidism had athyreosis
or ectopic thyroid gland. Sub-clinical hypothyroidism accounted for 32.9% of all cases; 10.7% showed a
spontaneous decrease to normal TSH levels and 13.6% had persistently elevated TSH levels with the median
follow-up time of 6 and 12 months, respectively. Congenital heart disease, gastrointestinal anomalies and
hematological disease were found in 73.6, 10 and 3.6 percent of patients, respectively. There was no statistical
correlation between the coexistence of cardiovascular or gastrointestinal disease in Down’s syndrome patients
with overt thyroid diseases or sub-clinical hypothyroidism to those having normal thyroid functions.
Conclusion : Sub-clinical hypothyroidism was the most common thyroid abnormality in children with Down’s
syndrome. A longitudinal and timely-scheduled evaluation of thyroid function is needed to establish the
natural course of this abnormality and the proper management guideline.
Keywords : Down’s syndrome, Abnormal thyroid function, Overt thyroid disease, Congenital hypothyroidism, Acquired hypothyroidism, Hyperthyroidism, Sub-clinical hypothyroidism, Congenital heart disease, Gastro- intestinal defect, Hematological disease
