Aase syndrome

Aase-Smith syndrome; Hypoplastic anemia - triphalangeal thumbs; Aase-Smith type; Diamond-Blackfan with AS-II; Aase-Smith I syndrome; Hydrocephalus-cleft palate-joint contractures syndrome; Aase-Smith syndrome type 1

Aase syndrome is a rare condition that involves a certain type of anemia and certain joint and skeletal deformities.

Causes

Many cases of Aase syndrome occur without a known reason and are not passed down through families (inherited). However, some cases have been shown to be inherited. These are due to a change in 1 of 20 genes important for making protein correctly (the genes make ribosomal proteins).

This condition is similar to Diamond-Blackfan anemia, and the two conditions should be considered the same. A missing piece on chromosome 19 is found in some people with Diamond-Blackfan anemia.

The anemia in Aase syndrome is caused by poor development of the bone marrow, which is where blood cells are formed.

Symptoms

Symptoms may include:

Absent or small knuckles
Cleft palate
Cleft palate
Cleft lip and palate are birth defects that affect the upper lip and the roof of the mouth.
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Deformed ears
Droopy eyelids
Inability to fully extend the joints from birth
Narrow shoulders
Pale skin
Pale skin
Paleness is an abnormal loss of color from normal skin or mucous membranes.
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Triple-jointed thumbs

Exams and Tests

Your health care provider will perform a physical exam. Tests that may be done include:

Bone marrow biopsy
Bone marrow biopsy
A bone marrow biopsy is the removal of marrow from inside one of your bones. Bone marrow is the soft tissue inside bones that helps form blood cells...
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Complete blood count (CBC)
Complete blood count
A complete blood count (CBC) test measures the following:The number of white blood cells (WBC count)The number of red blood cells (RBC count)The numb...
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X-rays
X-rays
X-rays are a type of electromagnetic radiation, just like visible light. An x-ray machine sends individual x-ray waves through the body. The images...
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Treatment

Treatment may involve blood transfusions in the first year of life to treat anemia.

A steroid medicine called prednisone has also been used to treat anemia associated with Aase syndrome. However, it should only be used after reviewing the benefits and risks with a provider who has experience treating anemias.

A bone marrow transplant may be necessary if other treatment fails.

Outlook (Prognosis)

The anemia tends to improve with age.

Possible Complications

Complications related to anemia include:

Fatigue
Decreased oxygen in the blood
Weakness

Heart problems can lead to a variety of complications, depending on the specific defect.

Severe cases of Aase syndrome have been associated with stillbirth or early death.

Prevention

Genetic counseling is recommended if you have a family history of this syndrome and wish to become pregnant.

Open References

References

Jones KL, Jones MC, del Campo M. Limb defect as major feature. In: Jones KL, Jones MC, del Campo M, eds. Smith's Recognizable Patterns of Human Malformation. 8th ed. Philadelphia, PA: Elsevier; 2022:428-459.

National Institutes of Health. National Center for Advancing Translational Sciences. Genetic and Rare Diseases Information Center website. rarediseases.info.nih.gov/diseases/5642/aase-smith-syndrome. Updated May 2026. Accessed May 26, 2026.

Thornburg CD. Congenital hypoplastic anemia (Diamond-Blackfan anemia). In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 497.

Complete blood count - series - Indication
Presentation

<strong>Complete blood count - series - Indication</strong><p>The complete blood count (CBC) is test, used to diagnose and monitor numerous diseases. It can reflect problems with fluid volume (such as dehydration) or loss of blood. It can show abnormalities in the production, life span, and destruction of blood cells. It can reflect acute or chronic infection, allergies, and problems with clotting. The CBC test identifies and counts the 7 types of cells found in the blood, red blood cell, neutrophil, eosinophil, basophil, lymphocyte, monocyte, and platelet.</p>

<strong>Procedure</strong><p>A CBC requires a small blood specimen. Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. To prepare, the skin should be cleaned with alcohol or iodine before the test. The patient should be seated comfortably or reclining. When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. After the blood is drawn, there may be some throbbing. Although the CBC test is very safe, any blood drawing has a slight risk of complication, including oozing of blood from puncture site; fainting or feeling lightheaded; hematoma (blood accumulating under the skin); multiple punctures to locate veins; or infection (a slight risk any time the skin is broken).</p>

<strong>Results, part 1</strong><p>Results; Normal values vary with altitude and sex. What abnormal results may mean; Low numbers of red blood cells may indicate blood loss; anemia (various types); hemorrhage; bone marrow failure (for example, from radiation, toxin, fibrosis, tumor); erythropoietin deficiency (secondary to renal disease); hemolysis (RBC destruction) from transfusion reaction; leukemia; multiple myeloma; malnutrition (nutritional deficiencies of iron, folate, vitamin B12, vitamin B6); or over hydration. Low numbers of white blood cells (leukopenia) may indicate bone marrow failure (for example, due to granuloma (granular tumor), tumor, or fibrosis); presence of cytotoxic substance; collagen-vascular diseases (such as lupus erythematosus); disease of the liver or spleen; or radiation exposure. High numbers of white blood cells (leukocytosis) may indicate infectious diseases; inflammatory disease (such as rheumatoid arthritis or allergy); leukemia; severe emotional or physical stress; or tissue damage (for example, burns). A low hematocrit may indicate anemia (various types); blood loss (hemorrhage); bone marrow failure (for example, due to radiation, toxin, fibrosis, tumor); hemolysis (RBC destruction) related to transfusion reaction; leukemia; malnutrition or specific nutritional deficiency; multiple myeloma; over hydration; or rheumatoid arthritis. A high hematocrit may indicate dehydration; burns; diarrhea; eclampsia; erythrocytosis; polycythemia vera; or shock. Low hemoglobin values may indicate anemia (various types) or blood loss.</p>

<strong>Results, part 2</strong><p>High numbers of red blood cells may indicate cigarette smoking; low oxygen tension in the blood; congenital heart disease; cor pulmonale; pulmonary fibrosis; polycythemia vera; dehydration (such as from severe diarrhea); or emphysema.</p>

Complete blood count - series - Indication
Presentation

A Closer Look

Talking to your MD

Self Care

Tests for Aase syndrome

Review Date: 7/28/2025

Reviewed By: Anna C. Edens Hurst, MD, MS, Associate Professor in Medical Genetics, The University of Alabama at Birmingham, Birmingham, AL. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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Health Library

Aase syndrome

Anemia

Causes

Symptoms

Cleft palate

Pale skin

Exams and Tests

Bone marrow biopsy

Complete blood count

X-rays

Treatment

Bone marrow transplant

Outlook (Prognosis)

Possible Complications

Stillbirth