Second, in contrast to serially collected NT-proBNP values, other parameters such as echocardiographic follow-up or functional tests performed over time, such as 6MWTs or cardiopulmonary exercise testing, as well as medication adjustments made during the course, were not fully available and could have provided further information on the influence and progression of recurrent HF events. The gene discussed is NPPB; the disease is hydrops fetalis.