A child surrounded by a DNA helix and a heart, symbolizing 18q deletion syndrome and its impact on heart health.

Rare Genetic Deletion Linked to Heart Defect: What Parents Should Know

Kai Mendoza in Health & Wellness December 2025 • 4 min read.

"A new case study highlights the connection between a specific genetic deletion (18q deletion syndrome) and a significant heart condition in newborns, offering critical insights for early diagnosis and care."

The 18q deletion syndrome is a rare genetic disorder, occurring in approximately 1 in 40,000 live births. This syndrome is characterized by the deletion of a portion of the long arm (q) of chromosome 18. While the size and location of the deletion can vary, leading to a wide range of symptoms, cardiac anomalies are frequently observed in affected individuals.

A recent case study published in the Annals of Laboratory Medicine details a newborn diagnosed with a de novo 18q22.1q23 deletion, meaning the deletion occurred spontaneously and was not inherited from either parent. What makes this case particularly noteworthy is the presence of a large atrial septal defect (ASD), a significant heart defect causing cyanosis (a bluish discoloration of the skin due to low oxygen levels).

This article aims to break down the key findings of this case study, explaining the connection between the 18q deletion syndrome and cardiac defects, particularly ASD. We will explore the diagnostic process, potential implications for affected children, and resources available for families.

Understanding 18q Deletion Syndrome and Its Impact on Heart Development

A child surrounded by a DNA helix and a heart, symbolizing 18q deletion syndrome and its impact on heart health.

The 18q deletion syndrome can manifest in various ways, affecting multiple systems in the body. While each individual experiences a unique combination of symptoms, some common features include developmental delays, intellectual disability, characteristic facial features, and, as highlighted in this case study, cardiac anomalies.

Cardiac defects associated with 18q deletion syndrome can range in severity and type, with ASD being a prominent finding. An ASD is a hole in the wall (septum) between the two upper chambers of the heart (atria). This hole allows oxygen-rich blood to leak from the left atrium into the right atrium, mixing with oxygen-poor blood. Large ASDs can lead to cyanosis, pulmonary hypertension, and other complications if left untreated.

Atrial Septal Defect (ASD): A hole between the heart's upper chambers can cause oxygen-rich and oxygen-poor blood to mix.
Ventricular Septal Defect (VSD): Similar to ASD, but the hole is between the lower chambers of the heart.
Tetralogy of Fallot: A combination of four heart defects that restrict blood flow to the lungs.
Pulmonary Stenosis: Narrowing of the pulmonary valve, making it harder for the heart to pump blood to the lungs.

The connection between 18q deletion syndrome and heart defects is believed to be related to the loss of critical genes located within the deleted region of chromosome 18. Several genes in this region play crucial roles in heart development, and their absence can disrupt the normal formation of the heart, leading to structural abnormalities like ASD.

What This Means for Families and Future Research

This case study underscores the importance of genetic testing in newborns presenting with unexplained cyanosis or suspected congenital anomalies. Early diagnosis of 18q deletion syndrome can facilitate timely intervention, including cardiac surgery to correct ASD and other associated health issues. Furthermore, understanding the specific genes involved in heart development within the 18q region can pave the way for targeted therapies and improved outcomes for affected individuals.

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Everything You Need To Know

What is the 18q deletion syndrome and what are its main implications?

The 18q deletion syndrome is a rare genetic disorder that happens when a part of the long arm (q) of chromosome 18 is missing. This deletion can cause various health issues because important genes in that area are missing. This can lead to developmental delays, intellectual disability, and distinct facial features. A significant implication is the possible development of cardiac anomalies, such as Atrial Septal Defect (ASD), underscoring the necessity for early diagnosis and intervention.

What is an Atrial Septal Defect (ASD) and why is it concerning?

An Atrial Septal Defect (ASD) is a hole in the wall (septum) between the two upper chambers of the heart (atria). This opening allows oxygen-rich blood to mix with oxygen-poor blood, leading to insufficient oxygen in the body. This can cause cyanosis, where the skin appears bluish. In severe cases, if left untreated, the condition may lead to pulmonary hypertension and other serious problems. The ASD's connection to 18q deletion syndrome is significant because it is a prominent cardiac anomaly that can greatly impact a newborn's health.

What was unique about the newborn's case mentioned?

The case study highlights a newborn with a de novo 18q22.1q23 deletion, meaning the deletion wasn't inherited. This specific deletion caused a large Atrial Septal Defect (ASD), which is a significant heart defect. The presence of ASD led to cyanosis in the newborn. It is noteworthy because it underscores the need for early genetic testing in infants presenting with cyanosis or suspected congenital anomalies, to aid in timely intervention.

Why does the 18q deletion syndrome cause heart defects?

The 18q deletion syndrome is linked to heart defects because the deleted region on chromosome 18 contains genes crucial for proper heart development. When these genes are missing, the heart may not form correctly. This can result in structural problems such as Atrial Septal Defect (ASD), Ventricular Septal Defect (VSD), Tetralogy of Fallot, or Pulmonary Stenosis. Because these genes are involved in the development of the heart, their absence directly influences the possibility of heart defects.

Why is early diagnosis of 18q deletion syndrome so important?

Early diagnosis is crucial because it enables timely intervention. Cardiac surgery can correct an Atrial Septal Defect (ASD), which is a hole between the heart's upper chambers. Understanding the genes within the 18q region helps in the creation of targeted therapies. Early diagnosis and proper interventions can significantly improve outcomes for children affected by 18q deletion syndrome. Genetic testing is very important for early detection and management.