non-immune hydrops fetalis Hb Bart's hydrops fetalis https://github.com/monarch-initiative/mondo/issues/7561 MEDGEN:543726 Hemoglobin Bart's hydrops fetalis UMLS:C0272005 SCTID:5300004 Alpha thalassemia caused by variation in all four copies of the alpha hemoglobin genes (e.g., homozygous deletion encompassing HBA1 and HBA2). Orphanet:163596 homozygous alpha0-thalassemia alpha-thalassemia hydrops fetalis Haemoglobin Bart's hydrops fetalis Hb Bart’s hydrops fetalis caused by quadallelic variation in HBA1;HBA2 HBA1;HBA2 digenic quadallelic Hb Bart’s hydrops fetalis ICD9:282.49 MONDO:0015579 GARD:0016992 Alpha-thalassemia major Hb Bart’s hydrops fetalis related to quadallelic variation in HBA1 and HBA2 digenic alpha thalassemia spectrum