Hemoglobin Beta Homozygous Null Genotype

**Semantic type:** Laboratory or Test Result

**Definition:** A genetic finding indicating that both copies of chromosome 16 each have a copy of the hemoglobin beta gene (HBB) with loss of function or gene deletion mutations (B0). This genotype is associated with beta thalassemia major.

**Synonyms:** - (B0/B0) - B0/B0 - HBB Homozygous Null Genotype - HBB Null Genotype - beta-globin genotype (B0/B0)