MDH1B and persistent fetal circulation syndrome: Eighteen of the PPHN-associated variants consisted of non-synonymous mutations in 14 genes; ANP32D, C12orf54, DR1, DUOXA1, FANCA, ITGAM, MBL2, MDH1B, PFKM, PLAU, PTX3, SIPA1L2, TMEM206, and TTLL3 (Table 2).