Achondrogenesis type 1B is a severe autosomal recessive skeletal disorder, invariably fatal in the perinatal period.

[2] Achondrogenesis type 1B (ACG1B), one of the most serious forms of chondrodysplasia, is a perinatal-lethal condition in which a person dies either during pregnancy or soon after birth.

Because mutations in the SLC26A2 gene alter the structure of growing cartilage, improper bone formation occurs, leading to the skeletal issues typical with achondrogenesis type 1B.

[2] Because achondrogenesis type 1B is inherited in an autosomal recessive manner, each cell's two copies of the SLC26A2 gene are mutated.

A person with an autosomal recessive disorder typically has parents who each carry one copy of the defective gene but do not exhibit the condition's symptoms.