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At a glance

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.

Genetic inheritance

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


Decreased erythropoiesis. The anemia is caused by underdevelopment of the bone marrow.


Based on the presence of bilateral triphalangeal thumbs at birth and the development of severe anemia that usually presents at age 6 months.

Clinical aspects

Mild growth deficiency, third percentile. The presence of congenital hypoplastic anemia tends to improve with age. Frequent transfusions are needed, often requiring chelation therapy. Bilateral triphalangeal thumbs noticed at birth. Narrow shoulder, radial hypoplasia, cleft lip/palate, and Dandy-Walker cyst may be present. It is also characterized by late closure of the cranial fontanelles. Patients occasionally receive steroid therapy. Affected individuals manifest an inability to fully extend the joints at birth due to severe congenital contractures. It is rarely associated with spontaneous remission.

Precautions before anesthesia

Check hemoglobin and transfuse as needed. Check for systemic signs of iron overload, specifically hepatic cirrhosis, ventricular septal defect, and the possibility of left heart cardiac failure.

Anesthetic considerations

The hematocrit should be assessed preoperatively. Maintain oxygen-carrying capacity. Avoid myocardial depressants, especially with preexisting failure. Peripheral vascular access and placement of radial arterial catheter are difficult.

Pharmacological implications

No specific implications for this condition.


Muis  M: Aase syndrome: Case report and review of the literature. Eur J Pediatr 145:153, 1986.  [PubMed: 3732321]
Yetgin  S, Balci  S, Irken  G,  et al: Aase-Smith syndrome. Turk J Pediatr 36:239, 1994.  [PubMed: 7974814]

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