Introduction

Choroideremia is a rare, inherited retinal disorder characterised by the progressive degeneration of the choroid, retinal pigment epithelium (RPE), and photoreceptors, resulting in gradual vision loss. It happens because of a change (mutation) in a gene called CHM. This gene normally encodes a protein used for maintaining the health of the eye’s cells. When it doesn’t work properly, the layers at the back of the eye (the choroid, retinal pigment, and photoreceptors) begin to weaken. It starts with night blindness in childhood, a gradual loss of side (peripheral) vision, and later evolves to central vision problems in adulthood.¹

How is choroideremia inherited?

Choroideremia is passed on in families through the X chromosome, which contains the CHM gene. This is called X-linked inheritance:

• Males who inherit the mutated CHM gene usually develop the condition²
• Females who carry the faulty CHM gene are usually healthy but may have mild changes in their vision: it’s called a recessive inheritance pattern¹
• An affected father will pass the changed CHM gene to all of his daughters (carriers), but none of his sons
• A carrier mother has a 50% chance of passing the mutated CHM gene to each child; sons may be affected, and daughters may become carriers

Why genetic counselling matters?

Genetic counselling is an important part of care for families living with choroideremia.³ It can help with:

Understanding family risk

Counsellors explain how the condition is inherited and who in the family may be at risk. The pedigree analysis helps the counsellor understand the inheritance pattern (for example, X-linked and recessive in this case) and implications for male and female relatives.⁴

Genetic testing

A simple test can confirm whether someone carries the CHM gene change. This helps with diagnosis and family planning.

Family planning choices and predictive testing

For families who want children, options like early pregnancy testing or preimplantation genetic testing (PGT) during IVF may be available. These choices are explained in a supportive, neutral way by the counsellor. Predictive testing for asymptomatic family members at risk can clarify their genetic status.⁵

Emotional support

Finding out that a family member has a genetic condition can be overwhelming. Families often face guilt, anxiety, and uncertainty regarding the progressive nature of the disease. Counsellors provide a safe space to discuss feelings of worry, guilt, or fear.⁵

Discussion of research and emerging therapies

While there is no cure yet, clinical trials are testing gene therapy to replace the missing protein in the eye. Gene therapy using adeno-associated virus (AAV)-mediated CHM gene offers hope for disease curation. Many families find hope in knowing research is moving forward.⁶ Counsellors should balance realistic expectations with optimism about research progress.

Challenges in genetic counselling for choroideremia

Choroideremia raises some specific challenges for genetic counselling beyond the usual aspects of X-linked disorders. Here are the main ones:

Complexity of X-linked inheritance

Families may struggle to understand how the condition is inherited. Therefore, in practice, counsellors would find it challenging to explain some inheritance concepts, specifically in this case: why only males are usually affected, but females can be carriers? And why can affected fathers not pass it to sons, but all daughters are carriers?⁷

Carrier detection in females

Female carriers are often asymptomatic, but some may show subtle retinal changes. This variability can cause uncertainty and anxiety for women learning about their carrier status. Therefore, carriers may face difficult decisions regarding family planning when penetrance is variable.⁷

Psychological and emotional burden

Progressive, untreatable vision loss creates emotional distress for patients and families. Therefore, parents may feel guilt about “passing on” the mutation. Moreover, young adults may experience anxiety about the future, independence, and career planning.⁸

Reproductive decision-making

Making family planning decisions stresses the family. Therefore, options like preimplantation genetic testing (PGT) or prenatal testing may raise ethical, cultural, or religious concerns. But in regions with limited access to assisted reproductive technology, these choices may not be realistic.

Limited treatment options

Although gene therapy trials are ongoing, there is still no widely available cure, which causes a feeling of uncertainty in patients and their families. Therefore, counselling becomes challenging: patients want hope but need realistic expectations.

Access to testing and specialised care

Genetic testing for CHM mutations may not be available everywhere. Therefore, families in low-resource regions may face barriers in confirming the diagnosis or accessing genetic counselling.

Practical strategies genetic counsellors can use

Strategies to address counselling for patients diagnosed with choroideremia consist of using visual aids, offering repeated consultations, linking families to patient advocacy organisations, and ensuring culturally sensitive counselling approaches. Here are practical strategies genetic counsellors can use to overcome the challenges in choroideremia cases: ⁸

Explaining X-linked inheritance clearly

• Use visual tools such as pedigree charts or infographics to explain why males are affected and females are carriers
• Provide simple key messages:
  • Example 1: Affected fathers would not have affected sons, but all daughters would be carriers
  • Example 2: Carrier mothers have a 50% chance of an affected son and a 50% chance of a carrier daughter
• Repeat information in different ways and check for understanding
  

Supporting carrier women

• Offer regular retinal examinations and molecular testing to confirm whether a woman is a carrier, as early detection helps anticipate possible health issues. These assessments also provide a clearer picture for family planning and medical decision-making
• Carriers may experience different levels of symptoms, ranging from no vision problems to significant impairment, depending on individual variation. Explaining this variability helps women understand the unpredictability and reduces anxiety related to their future health
• Genetic counselling before results are shared helps prepare women emotionally and provides them with realistic expectations. Follow-up counselling after results provides support, helping them process the information and make informed choices about their health and family

Addressing psychological burden

• Provide regular psychosocial support instead of limiting care to a single consultation, as the emotional impact of genetic conditions often evolves. Continuous support helps individuals and families adapt more effectively to new challenges and maintain their resilience
• Peer groups create a safe space for families to share experiences, coping strategies, and emotional support. Connecting with others who face similar challenges can reduce isolation and ensure a sense of community

Reproductive decision-making

• All reproductive options, including natural conception, prenatal testing, and preimplantation genetic testing (PGT), should be explained in a balanced and unbiased manner. This enables families to make informed decisions based on accurate information
• Each family’s decisions are shaped by their cultural beliefs, religious perspectives, and financial situation, which must be acknowledged during counselling. Tailoring discussions to these values ensures that recommendations are both respectful and realistic
• When families need further guidance or access to advanced reproductive technologies, timely referrals to fertility or reproductive specialists should be provided. This ensures they receive expert advice and the most up-to-date options available

Balancing hope and realism

• Families should be informed about ongoing clinical trials, such as gene therapy studies for choroideremia, so they are aware of potential emerging treatments. Providing current information empowers them to consider participation while staying hopeful about future medical advances
• It is important to explain that clinical trials and new therapies remain experimental and may not guarantee success. At the same time, supportive care options like low-vision rehabilitation and assistive devices can significantly improve quality of life in the present

Overcoming barriers to care

• Linking families to patient organisations gives them access to reliable information, advocacy resources, and opportunities to engage in research initiatives. Being part of a larger community also reduces feelings of isolation and provides mutual emotional support
• When molecular testing is unavailable, a clinical evaluation can still provide valuable insights for monitoring disease progression. Families should understand that clinical diagnosis remains a useful tool for making informed decisions about family planning and follow-up care
• Optimal care requires collaboration among different specialists, including geneticists, ophthalmologists, and psychologists. This team-based approach ensures that families receive comprehensive support addressing both medical and psychosocial needs

Summary

Choroideremia is a medical condition where counselling plays a critical role in managing inherited retinal diseases. Beyond confirming the genetic diagnosis, counselling provides risk assessment, guidance in reproductive decisions, emotional support, and updated knowledge about emerging therapies. Practical strategies employed by counsellors, such as using patient-friendly leaflets and simplifying key terms, help overcome several challenges faced during counselling.