Thyroid status and autoantibodies in first degree relatives of children with autoimmune thyroiditis

Objectives To see if the first degree relatives of the children with autoimmune thyroid disease (AITD) may have clinical or sub-clinical thyroid abnormalities

Methods In this cross-sectional study, we studied 50 first-degree relatives of 50 children with proven AITD for the evidence of any abnormal thyroid function

Results Three study subjects (6%) were found to have overt hypothyroidism and 1 had asymptomatic goiter on examination. None was found to have features of hyperthyroidism. TPO-positive subjects had significantly low mean T3 levels (1.2 ±0.4 ng/mL; p=0.005) and high TSH (23.01±42.5 µIU/mL; p=0.0001) when compared with the corresponding levels (T3=1.63± 0.4ng/mL & TSH= 5.5 ±16.6 µIU/mL) in the TPO negative subjects. A significant proportion of the patients (67%) with TPO positivity were found to have raised TSH levels. TPO positivity was found to have 100% correlation with manifestation of hypothyroidism in mothers and sisters. TG antibodies were positive in 32 (64%) subjects predominantly in fathers (77%). TG positivity was found to have poor correlation with any clinical or biochemical thyroid abnormality. Both antibody positivity was found in 5 (10%) subjects (22% in fathers only) and these subjects were found to have low mean T3 (1.6± 0.4ng/mL; p=0.005) and high mean TSH levels (36.5± 5.6 µIU/mL; p=0.011) when compared with the anti-body negative individuals.

Conclusions Thyroid dysfunction can be detected in a significant proportion of first degree relatives of AITD children and may represent an initial phase of the disease which need to followed closely