Medical condition characterized by the presence of bilateral triphalangeal thumbs at birth, congenital hypoplastic anemia usually developing at age 6 months, severe joint contractures and skeletal deformities, delayed cranial fontanelle closures, and poor peripheral vascular access. Affected individuals may present a ventricular septal defect leading to congenital left heart failure.

Aase-Smith Variant; Aase Congenital Anemia; Blackfan-Diamond Anemia Variant.

First described in 1969 in two male siblings by Jon Morton Aase, an American pediatrician.

Autosomal recessive transmission with normal chromosomes but also believed to possibly be autosomal dominant. Genetic basis of the disease is not known.