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Bilateral triphalangeal thumbs, congenital hypoplastic anemia, joint and skeletal deformities, delayed fontanelle closure, poor peripheral vascular access, possible ventricular septal defect.


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.


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


Based on bilateral triphalangeal thumbs at birth and anemia that usually presents at age 6 months.


Mild growth deficiency, third percentile. Congenital hypoplastic anemia tends to improve with age. Frequent transfusions are needed, often requiring chelation therapy. Bilateral triphalangeal thumbs. Narrow shoulder, radial hypoplasia, cleft lip/palate, and Dandy-Walker cyst may be present. Late closure of the fontanelles. Patients occasionally receive steroid therapy. Inability to fully extend the joints from birth (congenital contractures). Rarely spontaneous remission.


Check hemoglobin and transfuse as needed. Check for systemic signs of iron overload, specifically hepatic cirrhosis and cardiac failure.


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.


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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