Background: Thyroid dysgenesis has been considered a sporadic disease, but recent observations suggested a possible genetic basis.
Objective and hypotheses: The aim of our report is to evaluate the incidence of hormonal and ultrasound thyroid anomalies in siblings of CH patients with thyroid dysgenesis.
Method: In Emilia-Romagna Region (Italy) 328 CH infants were diagnosed by neonatal screening between January 2000 and December 2012. 122 cases of permanent CH due to thyroid dysgenesis were enrolled in this study (63 ectopic gland, 28 athyreosis, and 31 hypoplasia). Inclusion criteria were: confirmation of CH diagnosis at our screening centre, parents informed consent, and availability of thyroid hormonal and US data in siblings of CH cases.
Results: In 49/122 families 65 siblings (seven twins) over the CH patient were found. 19/65 subjects (29.2%) showed subclinical hypothyroidism (TSH range 5.38113.4 mU/l; FT4 range 10.116.6 pmol/l; thyroid antibodies negative in all cases) with thyroid in situ (normal volume in 14 cases, hypoplasia in four cases and goiter in one case). Thyroid anomalies were found in all twins examined. L-Thyroxine therapy was needed in seven cases. The median age at diagnosis was 5.5 years (range 14 days19 years). CH screening test was negative in all siblings. The frequency of positive history for thyroid diseases was similar in each group.
Conclusion: Monitoring of thyroid function is strongly recommended in siblings of patients with thyroid dysgenesis regardless of the result of the screening test. The type of thyroid disorders found in our sample of siblings seems to suggest a multifactorial origin of CH in which genetic and environmental risk factors can play a role.
18 Sep 2014 - 20 Sep 2014