SNP Shot: Genomic Insights

Congenital diaphragmatic hernia (CDH) occurs when there's a flaw in the diaphragm, the muscle and tissue structure separating the abdomen from the chest. This defect arises during fetal development, ranging from a weak spot in the diaphragm to its total absence. When the diaphragm is missing or incomplete, an opening (hernia) forms, allowing abdominal organs like the stomach and intestines to shift into the chest. This crowding puts pressure on the heart and lungs, hindering lung development (pulmonary hypoplasia). This can cause severe, potentially fatal, breathing difficulties that are present at birth.

While most cases manifest at birth, 5 to 10 percent of individuals with CDH may not show symptoms until later in life. These later symptoms can include breathing issues or abdominal pain due to the intestine protruding into the chest. In around 1 percent of cases, CDH is asymptomatic and discovered incidentally during imaging procedures performed for unrelated medical reasons.

CDH cases are often categorized based on the location of the defect. A Bochdalek hernia, located on the side or back of the diaphragm, is the most common type, accounting for 80 to 90 percent of CDH cases. A Morgagni hernia, affecting the front of the diaphragm, represents approximately 2 percent of cases and is less likely to cause severe symptoms at birth. Other types of CDH are rare and include defects in the central region of the diaphragm or cases where the diaphragm muscle is absent, replaced only by a thin membrane.

Inheritance:

Isolated CDH is typically not inherited. In almost all cases, only one person in a family is affected. However, when CDH is present as part of a genetic syndrome or chromosomal abnormality, it can appear in multiple family members, following the inheritance pattern of that specific condition.