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Genetic and Rare Diseases Information Center (GARD)

Hypoplastic left heart syndrome

Other Names for this Disease
  • HLHS
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What are the signs and symptoms of Hypoplastic left heart syndrome?

Normally, oxygen-poor blood is pumped through the right side of the heart to the lungs, where it gains oxygen and returns to the left side of the heart. The oxygen-rich blood is then pumped from the left side of the heart to the rest of the body. At birth, all babies also have two connections, or shunts, between the two sides of the heart; however, within a few days of birth these connections close. In those with HLHS, the underdeveloped left side of the heart is unable to provide enough blood flow to the body. The normal shunts present at birth help to direct blood to the body; when these connections close the oxygen-rich blood supply decreases.[1]

At first, a newborn with HLHS may appear normal. Symptoms usually occur in the first few hours of life, although it may take up to a few days to develop symptoms. These symptoms may include:[2]

  • Bluish (cyanosis) or poor skin color
  • Cold hands and feet (extremities)
  • Lethargy
  • Poor pulse
  • Poor suckling and feeding
  • Pounding heart
  • Rapid breathing
  • Shortness of breath

In healthy newborns, bluish color in the hands and feet is a response to cold (this reaction is called peripheral cyanosis). However, a bluish color in the chest or abdomen, lips, and tongue is abnormal (called central cyanosis). It is a sign that there is not enough oxygen in the blood. Central cyanosis often increases with crying.[2]
Last updated: 7/21/2011

The Human Phenotype Ontology provides the following list of signs and symptoms for Hypoplastic left heart syndrome. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms.

Signs and Symptoms Approximate number of patients (when available)
Hypoplastic left heart 90%
Abnormality of the aorta 50%
Abnormality of chromosome segregation 7.5%
Abnormality of the mitral valve 7.5%
Atria septal defect 7.5%
Maternal diabetes 7.5%
Patent ductus arteriosus 7.5%

Last updated: 7/1/2016

The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature.

The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined.

Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.

  1. Facts about Hypoplastic Left Heart Syndrome. Centers for Disease Control and Prevention. April 2011; Accessed 7/21/2011.
  2. Schumacher KR. Hypoplastic left heart syndrome. MedlinePlus. December 2009; Accessed 7/21/2011.

Other Names for this Disease
  • HLHS
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.