Is Usher syndrome a hereditary condition passed from parents to children?

Yes, Usher syndrome is a hereditary condition passed from parents to children through genes [2]. It occurs due to genetic mutations that lead to abnormal development of the sensory cells in the inner ear and the retina of the eye [3]. To understand how it is transmitted, it is important to know that it follows an autosomal recessive inheritance pattern.

How is Usher syndrome inherited?

Usher syndrome is inherited as an autosomal recessive disorder, which means that a person must inherit two copies of the mutated gene, one from each biological parent, to develop the disease [1]. If a person carries only one copy of the mutated gene, they are considered a carrier of the disease and usually do not exhibit symptoms [3].

• Carrier parents: If both parents are carriers of the mutated gene (each has one copy of the mutated gene), there is a 25% chance that their child will inherit two copies of the mutated gene and develop Usher syndrome. There is also a 50% chance that the child will inherit only one copy of the gene and become a carrier, and a 25% chance that the child will inherit two normal copies of the gene and will neither be affected nor a carrier [1].
• Involved genes: Researchers have identified nine different genes that can cause Usher syndrome, which are categorized according to the types of the syndrome [2]. For example, the genes MYO7A, USH1C, CDH23, PCDH15, and USH1G are associated with type I, while the genes USH2A, GPR98, and DFNB31 are associated with type II, and the CLRN1 gene is associated with type III [3].

Types of Usher syndrome and the impact of inheritance

Usher syndrome is classified into three main types, which vary in the severity of hearing loss, the presence of balance problems, and the age at which symptoms appear [1]:

• Type I: Most individuals with this type are born with severe to profound hearing loss and balance problems. Vision loss resulting from retinitis pigmentosa begins to appear in childhood, affecting night and peripheral vision [2].
• Type II: This type is characterized by moderate to severe hearing loss at birth, but it is usually not associated with balance problems. Vision loss begins to appear during adolescence or adulthood [1].
• Type III: Individuals with this type are born with normal hearing, and hearing and vision loss begin later in life, usually in late childhood or adolescence. Some may develop balance problems [1].

The importance of genetic counseling and early diagnosis

Given the hereditary nature of Usher syndrome, genetic counseling plays a crucial role for families with a history of the disease or those who suspect its presence [1]. Genetic testing can help confirm the diagnosis and identify the specific type of Usher syndrome, allowing for an appropriate treatment and management plan [3]. Early diagnosis is important to maximize the benefits of available therapeutic interventions, such as hearing aids or cochlear implants, and vision rehabilitation services [2]. To learn more about the challenges associated with hearing and vision and early intervention, you can visit Usher Syndrome: Understanding Hearing and Vision Challenges and Early Intervention (Arabic).

What to do if you suspect Usher syndrome?

If you suspect that your child or a family member may have Usher syndrome, it is essential to consult a specialist physician immediately [2]. A comprehensive diagnosis may include an extensive eye exam, hearing and balance tests, as well as genetic testing [2]. Collecting the family's health history, including any family members who suffer from similar symptoms, can provide valuable information to the medical team [1]. There is currently no cure for Usher syndrome, but early treatments can help manage symptoms and improve quality of life [2].

Medical references

• Usher syndrome
• Usher Syndrome
• Usher Syndrome