Further analysis with stratification by sex, there was a significant NGFR genotype effect on HF (F = 13.29, p < 0.001) and RMSSD (F = 7.69, p = 0.006) in men, but not in women (HF: F = 0.48, p = 0.49; RMSSD: F = 0.65, p = 0.42) (Table 4). The gene discussed is NGFR; the disease is hydrops fetalis.