Who gets cystic fibrosis the most? A demographic and genetic overview

October 2, 2025 •

3 min read

According to the Cystic Fibrosis Foundation, approximately 40,000 children and adults in the U.S. live with cystic fibrosis (CF). So, who gets cystic fibrosis the most? The prevalence of this inherited disease varies significantly by race and ethnic background, influenced by centuries of human genetic history.

Quick Summary

The genetic disorder cystic fibrosis is most common among people of Northern European Caucasian descent, with a significantly higher incidence rate compared to other ethnic groups like African Americans, Hispanics, and Asian Americans. A person must inherit one mutated gene from each parent to develop the condition.

Key Points

Caucasian Prevalence: The highest incidence of cystic fibrosis is found in people of Northern European Caucasian ancestry.
Autosomal Recessive Inheritance: CF is an autosomal recessive disorder, meaning an individual must inherit two copies of the mutated gene to develop the disease.
Carrier Status: The gene is most frequently carried by Caucasians (~1 in 29), making the risk of having an affected child higher in this group.
Global Impact: While less frequent in other groups, cystic fibrosis affects all ethnic populations worldwide and requires diverse genetic testing for accurate diagnosis.
F508del Mutation: The F508del mutation is the most common CFTR gene mutation and is most prevalent in Caucasian individuals.
Improved Diagnosis: Enhanced newborn screening methods are increasing detection rates in all ethnic groups, helping close historical gaps in diagnosis.

The genetic basis of cystic fibrosis

Cystic fibrosis is a genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. This gene provides instructions for making the CFTR protein, which regulates the flow of salt and water in and out of the body's cells. In people with CF, a faulty CFTR protein disrupts this process, leading to the production of abnormally thick and sticky mucus that clogs airways and various organs.

For a person to have CF, they must inherit two copies of a mutated CFTR gene—one from each biological parent. If a person inherits only one mutated gene, they become a CF carrier. Carriers do not have the disease but can pass the gene to their children. This autosomal recessive inheritance pattern is key to understanding its prevalence.

Cystic fibrosis demographics: Prevalence by ethnicity

While CF can affect people of any racial or ethnic background, its prevalence varies dramatically across different populations due to genetic ancestry. For example, the mutation most common in Caucasians, F508del, is not as frequent in other groups, where different, rarer mutations may occur.

Why are some populations more affected?

The disparity in CF prevalence is largely attributed to what is known as the "founder effect," where certain gene mutations become more common within specific, historically isolated populations. The high rate among Caucasians is thought to be linked to a selective advantage of being a CF carrier against certain diseases, like cholera, in past centuries. Over time, this led to a higher carrier rate and, consequently, a higher incidence of CF within this population.

The carrier connection

Understanding carrier rates is crucial for genetic counseling and family planning. The risk of having a child with CF is tied directly to the parents' carrier status.

Inheritance probability from carrier parents

For each pregnancy between two carrier parents, the chances are:

1 in 4 (25%) the child will have CF.
1 in 2 (50%) the child will be a carrier but not have CF.
1 in 4 (25%) the child will not have CF and will not be a carrier.

Ethnic differences in carrier rates:

Caucasians: Approximately 1 in 29 people are carriers.
Hispanic Americans: About 1 in 46 people are carriers.
African Americans: Around 1 in 65 people are carriers.
Asian Americans: About 1 in 90 people are carriers.

Comparison of CF incidence rates by ethnicity


Ethnic Group	Estimated Birth Incidence in the U.S.
White, non-Hispanic	~1 in 3,200
African American	~1 in 15,000
Asian American	~1 in 31,000
Hispanic	~1 in 9,200
Native American	~1 in 10,900

It is important to note that these figures are estimates and can vary depending on the data source and year collected. The Cystic Fibrosis Foundation Patient Registry provides detailed, updated statistics.

The evolving landscape of CF

Historically, CF was considered a disease affecting only Caucasians. However, increasing global awareness, better diagnostic tools, and improved newborn screening have led to more cases being identified across all ethnic backgrounds.

Non-white newborns with CF have historically been more likely to be missed in initial screening because many of the original gene panels were designed to detect mutations most common in Caucasian populations. As testing expands to include a wider array of mutations, diagnosis rates in minority populations are improving.

The role of CFTR mutations

Over 2,000 different mutations in the CFTR gene can cause cystic fibrosis, though the most common ones differ by ethnicity. The severity of the disease can depend on the specific mutation(s) inherited. For example, the F508del mutation is the most frequent worldwide and is often associated with more severe symptoms. However, less common mutations can result in a milder form of the disease.

Conclusion: The importance of genetic screening

While the answer to who gets cystic fibrosis the most points towards those of Northern European descent, it is a significant health concern for all populations. Genetic counseling and screening are important tools for couples with a family history of CF or those in higher-risk ethnic groups. Increased awareness and expanded screening panels are helping to ensure earlier and more accurate diagnoses for individuals across all backgrounds, leading to improved outcomes and a better quality of life for those living with the disease.

For more information on the latest statistics and genetic research, visit the official Cystic Fibrosis Foundation website: https://www.cff.org/.

Frequently Asked Questions

The main risk factor is inheriting two copies of a mutated CFTR gene, one from each parent. Family history is a key indicator, especially if either parent is a known carrier of the gene.

No, while CF is most common in Caucasians, it affects people of all racial and ethnic groups. Prevalence and carrier rates vary, with lower incidence in African American, Asian American, and Hispanic populations.

A person becomes a carrier by inheriting one copy of the mutated CFTR gene and one normal copy. The single normal gene is sufficient for normal cell function, so the person does not have symptoms but can pass the mutated gene to their children.

This is likely due to the 'founder effect,' where a specific gene mutation becomes more prevalent within a population that has been historically isolated. A theory suggests a selective advantage for carriers against past epidemics like cholera, increasing the frequency of the CF gene in the gene pool.

Historically, newborn screening panels were designed for mutations most common in Caucasians, potentially missing cases in other ethnic groups. Newer, expanded genetic tests are now available to improve detection across all populations.

Yes, while most cases are diagnosed by age two due to newborn screening, a small percentage of new diagnoses occur in adults. Those diagnosed later in life often have milder forms of the disease.

The CFTR gene provides instructions for creating the CFTR protein, which regulates the movement of chloride ions and water across cell membranes. Mutations in this gene disrupt this function, leading to the symptoms of cystic fibrosis.