What is the most common abnormality in Down syndrome, specifically Congenital Heart Defect (CHD), Leukemia, or Hirschsprung disease?

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From the Guidelines

The most common abnormality in Down syndrome is congenital heart defects, which occur in approximately 40% of cases, as stated in the study by 1. This is significantly higher than the incidence of other abnormalities such as leukemia and Hirschsprung disease. Some key points to consider are:

  • Congenital heart disease is present in 40% of Down syndrome cases, according to 1
  • Leukemia occurs in a much smaller percentage of the population, with an increased incidence of up to 20 times that of the general population, but still much lower than the incidence of congenital heart defects
  • Hirschsprung disease is also associated with Down syndrome, but at a frequency of only about 5%, as mentioned in 1 The high incidence of congenital heart defects in Down syndrome highlights the importance of early cardiac evaluation and management to reduce morbidity and mortality. Key factors to consider in the management of Down syndrome patients include:
  • Early cardiac evaluation to identify and address congenital heart defects
  • Monitoring for signs of leukemia and other abnormalities
  • Management of associated conditions such as gastrointestinal anomalies and neuronal degeneration.

From the Research

Abnormalities in Down Syndrome

The most common abnormality in Down syndrome is Congenital Heart Defect (CHD). According to the studies, approximately 50% of children with Down syndrome have CHD 2, 3, 4.

Types of Congenital Heart Defects

The most common types of CHD in Down syndrome are:

  • Ventricular septal defect (VSD) 2, 3, 4
  • Atrioventricular septal defect (AVSD) 2, 3, 4
  • Atrial septal defect (ASD) 2, 3, 4
  • Patent ductus arteriosus (PDA) 2, 3, 4
  • Tetralogy of Fallot (TOF) 2, 3, 4

Comparison with Other Abnormalities

In comparison to CHD, Leukemia and Hirschsprung disease are less common in Down syndrome. While Leukemia is mentioned as a cause of death in some cases 4, Hirschsprung disease is reported to occur in a smaller percentage of cases 3, 5.

Prevalence of CHD

The prevalence of CHD in Down syndrome is reported to be around 49.8% to 61.3% in different studies 2, 3, 4. The survival rate of patients with Down syndrome and CHD is lower than those without CHD 4.

Factors Associated with CHD

Some studies have found associations between the incidence of CHD and factors such as sex and ethnicity 6. However, more research is needed to fully understand the genetic and environmental risk factors associated with CHD in Down syndrome.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Survival analysis of Down syndrome with congenital heart disease: a 5-years registry at QSNICH.

Journal of the Medical Association of Thailand = Chotmaihet thangphaet, 2014

Research

Associated congenital anomalies among cases with Down syndrome.

European journal of medical genetics, 2015

Research

Ethnicity, sex, and the incidence of congenital heart defects: a report from the National Down Syndrome Project.

Genetics in medicine : official journal of the American College of Medical Genetics, 2008

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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