Aase-Smith syndrome, also known as congenital hypoplastic anemia with triphalangeal thumbs, is a rare genetic disorder that affects blood cell production and the development of the thumbs. The syndrome is named after the Norwegian pediatrician Jon Aase and the American pediatrician David Smith, who both independently described the syndrome in the 1960s.
The primary feature of Aase-Smith syndrome is congenital hypoplastic anemia, which means that the body does not produce enough red blood cells. This can lead to symptoms such as fatigue, weakness, and pale skin. Additionally, people with Aase-Smith syndrome have thumbs that are shaped differently than usual, with only three bones instead of the normal two joints and three bones.
Aase-Smith syndrome is caused by mutations in the RBM8A gene, which provides instructions for making a protein that plays a role in the production of red blood cells. The exact way that these mutations lead to the characteristic features of Aase-Smith syndrome is not well understood.
Diagnosis of Aase-Smith syndrome is based on clinical features such as congenital hypoplastic anemia and triphalangeal thumbs, as well as genetic testing to confirm the presence of mutations in the RBM8A gene.
Treatment for Aase-Smith syndrome is focused on managing the symptoms of anemia, which may include blood transfusions, medication, and sometimes bone marrow transplantation. Orthopedic interventions may be necessary for the thumb abnormalities. While there is no cure for Aase-Smith syndrome, with appropriate medical care and support, most people with the condition can lead relatively normal lives.