NATURAL COURSE OF SUBCLINICAL HYPOTHYROIDISM IN DOWNS-SYNDROME - PROSPECTIVE-STUDY RESULTS AND THERAPEUTIC CONSIDERATIONS

Pathogenesis, natural course and therapeutic management of subclinical hypothyroidism (SH) in Down's syndrome (DS) remain object of debate i n literature. In the present study thyroid function, antithyroid antib ody (ATA) prevalence and serum lipid concentrations were investigated in a group of 344 Down patients (DP) and data were compared with those obtained from a control group of 257 age and sex matched healthy subj ects. Thyroid function and ATA prevalence were also studied in 120 par ents of DP. SH prevalence was clearly higher in DP (32.5% of cases) th an in controls (1.1%) and parents (0%). Similarly, ATA prevalence was higher in DP (18% of cases) than in controls (5.8%) and parents (6.6%) . in spite of this, no correlation was found in DP between SH and ATA prevalences, since ATA were detected in 18.7% of SH-DP and in 15.8% of euthyroid DP. Thus, circulating ATA were not detected in the majority of SHDP. No significant differences regarding T4, FT4, T3 and serum l ipid levels among SH and euthyroid DP and controls were found. Moreove r, TSH levels were only slightly increased, generally less than 10 mu U/ml, in most cases of SH-DP. Follow-up was longer than 24 months (ran ge 2-7 years, mean 3.1) in a group of 201 DP: two different patterns o f SH course were observed, mainly depending on the