triiodothyronine--reverse and Down-Syndrome

Plasma levels of TSH, T4, T3, and reversal T3 (rT3) were measured in 51 children with trisomy of the chromosome 21 and in 15 controls. Levels of TSH were higher in children with DS than in controls and rT3 levels were decreased. However, T3 and T4 levels were in the normal range. Plasmic zinc and thymulin, a zinc-dependent thymic hormone, were also decreased. After dietary supplementation with ZnSO4, levels of plasmic zinc, thymulin, TSH and rT3 were restored. A follow up of DS children one year after the cessation of zinc therapy showed that plasma levels of zinc decreased and TSH lightly increased. Zinc deficiency may play a crucial role in the pathogenesis of thyroid gland disfunction which leads to the autoimmune hypothyroidism often observed in this syndrome.

Topics: Down Syndrome; Female; Follow-Up Studies; Humans; Male; Sulfates; Thymic Factor, Circulating; Thyroid Hormones; Thyrotropin; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse; Zinc; Zinc Compounds; Zinc Sulfate

Down Syndrome (DS) or trisomy 21 (T21) is the most frequent and the best known malformation syndrome associated with mental deficiency that appears in human,. Average incidence of this syndrome is about 1:700 newborns. Numerous researchers noted thyroid disorders in people with Down Syndrome but, clinical symptoms of thyroid dysfunction are difficult to separate from DS phenotype. The aim of this study was to examine the thyroid function in the patients with DS. Our results confirmed higher frequency of thyroid dysfunction in DS patients. Higher values of TSH were found in 60,34% of the examined DS patients, which is significantly higher value comparing with the control group (p<0,01). Compensated hypothyroidism was established in 27,92% of the examined DS patients, and most of those (63,23%) were younger than 6 years. The conclusions emphasize the necessity of implementation of thyroid function screening program in persons with DS, and the need for adequate treatment of its dysfunction. Thus, the symptoms of the disease would be alleviated and better physical and mental fitness ensured.

Topics: Adolescent; Age Factors; Child; Child, Preschool; Down Syndrome; Female; Humans; Infant; Infant, Newborn; Male; Thyroid Diseases; Thyroid Function Tests; Thyroid Gland; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse

Abnormal thyroid function was shown in children with Down syndrome (DS). This study was undertaken in order to specify these anomalies.. Thyroid function of 105 children with DS aged from 3 months to 20 years was studied by evaluation of serum concentration of thyrotropin, free T4 (FT4), free T3 (FT3) and reverse T3 (rT3). Each DS child was matched to a control of the same age.. The mean concentration of thyrotropin of children with DS was increased while the mean concentration of rT3 of the DS children was significantly decreased compared with the controls, as was the ratio rT3/TSH. When DS children are split into two groups, those with and those without increased thyrotropinemia, a significant decrease in the ratio rT3/TSH appeared in DS children with increased thyrotropinemia whereas there is no difference between these two groups regarding to level of FT4, FT3, rT3 and zincemia. However, in all DS children serum zinc levels were lower than in controls. Thyrotropin levels rapidly normalized after thyroxin treatment.. One half of the children with DS have increased thyrotropinemia and all have a decreased rT3.

Topics: Adolescent; Adult; Age Determination by Skeleton; Child; Child, Preschool; Down Syndrome; Female; Humans; Infant; Male; Thyroid Diseases; Thyrotropin; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse

Topics: Adolescent; Child; Child, Preschool; Down Syndrome; Humans; Infant; Prospective Studies; Triiodothyronine, Reverse

3,3'5'-triiodothyronine (rT3) levels have been documented to be low in patients with Down syndrome but the metabolic implications of this finding remain unknown. A highly significant correlation was found between the in vitro variations of the mitotic index in lymphocyte cultures when rT3 or known inhibitors of inosine monophosphate dehydrogenase: mycophenolic acid, 6-mercaptopurine or 2-3-diphosphoglycerate were added. No significant difference was found between the response of trisomy 21 or normal lymphocytes. The finding suggests that rT3 may be a physiological modulator of inosine monophosphate dehydrogenase. The implications on cellular differentiation are discussed.

Topics: 2,3-Diphosphoglycerate; Cells, Cultured; Diphosphoglyceric Acids; Down Syndrome; Humans; IMP Dehydrogenase; Ketone Oxidoreductases; Mercaptopurine; Mitosis; Mitotic Index; Mycophenolic Acid; Triiodothyronine, Reverse

An excess of thyrotropin (TSH) with normal levels of tetraiodothyronine (T4) and of 3,5,3'-triiodothyronine (T3) was confirmed in the serum of 78 trisomy 21 children. A severe deficiency of 3,3',5'-triiodo-thyronine (rT3 or reverse T3) was observed and the decrease of the rT3/TSH ratio was highly significant. These new facts suggest that the rT3 deficiency plays a peculiar role in trisomy 21 (maybe through the regulation of one or few steps of monocarbons' metabolism). A systematic control of thyroid function (including the patient's rT3 level) is mandatory for the follow-up of every trisomy 21 patient.

Topics: Adolescent; Child; Child, Preschool; Down Syndrome; Female; Humans; Infant; Male; Models, Molecular; Reference Values; Thyroid Gland; Thyrotropin; Thyroxine; Triiodothyronine, Reverse