<unk>  is primarily an autosomal recessive genetic disorder. This means that two mutated alleles (one from each parent) are required to cause the disease. The risk is 25% that each subsequent child will have<unk> . About 2% of<unk>  cases are X-linked recessive, which means that if the mother carries one mutated<unk>  allele on one X chromosome, a 50% chance exists that male offspring will present with<unk> . Scientists have identified 21<unk>  or<unk> -like genes:<unk> NCA,<unk> NCB,<unk> NCC,<unk> NCD1 (BRCA2),<unk> NCD2,<unk> NCE,<unk> NCF,<unk> NCG,<unk> NCI,<unk> NCJ (BRIP1),<unk> NCL,<unk> NCM,<unk> NCN (PALB2),<unk> NCO (RAD51C),<unk> NCP (SLX4),<unk> NCQ (XPF),<unk> NCS (BRCA1),<unk> NCT (UBE2T),<unk> NCU (XRCC2),<unk> NCV (REV7), and<unk> NCW (RFWD3).<unk> NCB is the one exception to<unk>  being autosomal recessive, as this gene is on the X chromosome. These genes are involved in DNA repair. The carrier frequency in the Ashkenazi Jewish population is about one in 90. Genetic counseling and genetic testing are recommended for<unk> milies who may be carriers of<unk> . Because of the<unk> ilure of hematologic components—white blood cells, red blood cells, and platelets—to develop, the body's capabilities to fight infection, deliver oxygen, and form clots are all diminished.
Fanconi anemia
Diamond–Blackfan anemia
XMEN disease
Beta thalassemia
Delta-beta thalassemia
Hemoglobin Lepore syndrome
Sick cell syndrome
Hereditary spherocytosis