Genetic Testing Rate Lower for Blacks With Inherited Retinal Diseases

(HealthDay News) — The genetic testing rate is lower for Black than non-Hispanic White patients with inherited retinal diseases (IRDs), according to a study published online Nov. 7 in JAMA Ophthalmology.

Rebhi O. Abuzaitoun, M.D., from the University of Michigan Medical School in Ann Arbor, and colleagues examined the genetic detection rates of wide-panel testing in Black and non-Hispanic White patients with IRDs using retrospective patient data collected at the University of Michigan (UM) and Blueprint Genetics (BG).

A total of 572 patients were included in UM (9.4 percent Black; 90.6 percent White), while the BG database included 320 Black patients and 2,931 White patients. The researchers found that at UM, there were independent associations for Black race (odds ratio, 0.25) and age (odds ratio per 10 years, 0.84) with reduced odds of a positive test. In the BG database, 44.4 and 57.7 percent of Black and White patients, respectively, had a positive/likely positive result.

“Given that patients with no known genetic diagnosis have fewer options for receiving novel treatments, the equity of genetic testing directly impacts the equity of IRD clinical trials,” the authors write. “As future treatments become available, we must critically examine the genetic detection rates across majority and minority subgroups alike.”

Authors disclosed ties to Blueprint Genetics and ExamOne (owned by Quest Diagnostics).

What are inherited retinal diseases (IRDs)?

Inherited retinal diseases (IRDs) are a group of eye disorders that affect the retina, the light-sensitive tissue at the back of the eye. These conditions are caused by genetic mutations and can lead to vision loss, including blindness. While IRDs can affect people of all backgrounds, certain conditions may disproportionately impact specific populations, including Black Americans.  

What are common IRDs Affecting Black Americans?

• Retinitis Pigmentosa (RP): This is one of the most common inherited retinal diseases, causing progressive vision loss, often beginning with night blindness and tunnel vision. RP can affect people of all ethnicities, but certain forms, such as X-linked RP, are more prevalent in individuals of African descent.  
  
  
  

  
  
  
  
• Leber Congenital Amaurosis (LCA): LCA is a rare, inherited eye disease that causes severe vision loss from birth or early childhood. While less common than RP, LCA can affect individuals of all ethnicities, including Black Americans.   
  
  
  

  
  
  
  
• Usher Syndrome: This is a rare genetic disorder that affects both hearing and vision. Individuals with Usher syndrome experience progressive hearing loss and vision loss, often leading to blindness. While less common in Black Americans compared to other populations, it’s still important to be aware of this condition.  
  
  
  

  
  
  
  

Why IRDs might disproportionately affect Black Americans

• Genetic Factors: Specific genetic mutations linked to certain IRDs may be more prevalent in certain populations, including Black Americans.
• Lack of Awareness and Access to Care: Many IRDs are rare and may not be widely recognized or understood, particularly in underserved communities. This can lead to delayed diagnosis and treatment.   
  
  
  

  
  

  
  

  
  

  
  

  
  
  
  
• Limited Research and Clinical Trials: There is a need for more research and clinical trials focused on IRDs in diverse populations, including Black Americans. This would help identify specific risk factors and develop targeted treatments.

The importance of early diagnosis and genetic counseling

Early diagnosis of IRDs is crucial for timely intervention and management. Genetic counseling can help individuals understand their risk of passing on IRDs to their children and make informed decisions about family planning.

While IRDs can affect anyone, it’s important to be aware of the specific challenges faced by Black Americans in relation to these conditions. Increased awareness, early diagnosis, and access to quality healthcare are essential for improving the lives of individuals affected by IRDs.

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