In the clinical studies, there are conflicting results regarding the prognostic relevance of TH abnormalities, reflecting the heterogeneity of the population enrolled in terms of HF cause, sex, age, race, degree of TSH suppression, and duration of follow-up, modality of acquisition of the data and their fullness, time of TH sampling, and time of patient enrolment. The gene discussed is TH; the disease is hydrops fetalis.