Using the approach described by Li et al. [13], we identified 345 genes with extremely rare variants that were uniquely present only in our severely affected subjects, 19 of which were also among the 258 identified by Li et al. in their BPD cohort (CDH23, CHST10, DAAM1, DYDC1, FIGN, KIAA1468, MDN1, MYOZ1, NID2, NRXN3, NUP93, PICALM, ROR1, SETBP1, SYDE2, TBC1D1, TGFBI, YLPM1, ZHX3). The gene discussed is PICALM; the disease is bronchopulmonary dysplasia.