Hemoglobin Alpha cis-Deletion with Constant Spring Genotype

**Semantic type:** Laboratory or Test Result

**Definition:** A genetic finding indicating that one copy of chromosome 16 has one functional copy of a hemoglobin alpha (HBA) gene and one copy that encodes an HBA stop loss mutation called hemoglobin Constant Spring (CS), while the other copy of chromosome 16 has no functional HBA genes. This genotype is associated with a severe form of hemoglobin H disease.

**Synonyms:** - (--/aCSa) - (aCSa/--) - --/aCSa - HBA cis-Deletion with CS Genotype - HBA cis-Deletion with Constant Spring Genotype - aCSa/-- - alpha-globin genotype ( - - / aCSa)