Usher Syndrome

 Usher Syndrome

Overview

Usher syndrome is a rare inherited disorder that causes vision loss, hearing loss and, sometimes, balance issues. It happens because mutations (changes) in specific genes disrupt how hearing and vision develop during fetal development. Usher syndrome symptoms are often congenital (present at birth) or develop during childhood. Rarely, people with this condition develop symptoms as adults. There’s no cure for Usher syndrome, but there are many ways to manage its symptoms.

Types of Usher syndrome

There are 10 known mutations that lead to this disorder, and syndrome types vary depending on the different combinations of genetic mutations. But all types of Usher syndrome cause issues with hearing, vision and balance. The differences are when symptoms start and how severe those symptoms are.

The three types of Usher syndrome are:

Type 1: In this type, hearing loss and balance issues are present at birth. If your baby has this type of Usher syndrome, they have severe hearing loss or total hearing loss. They’ll have balance issues that affect when they start to walk. Later in childhood, your child may develop vision issues, starting with loss of night vision that gets worse as they grow older.

Type 2: Babies with Usher syndrome Type 2 are born with moderate to severe hearing loss. But they don’t have balance issues that may affect when they learn to walk. As teenagers, they may develop vision issues that get worse as they get older.

Type 3: This type is very rare. People with Type 3 Usher syndrome have typical hearing and vision when they’re born. They begin to develop hearing loss in late childhood and vision loss in early to mid-adulthood. Half of those with Usher syndrome Type 3 also have balance problems.

Symptoms

Symptoms vary and develop over time depending on the type of Usher syndrome. Common symptoms include:

Hearing loss: Some children with Usher syndrome are born deaf or with severe hearing loss. Others experience moderate hearing loss later in life.

Vision loss: Children with Usher syndrome experience vision loss due to a condition called retinitis pigmentosa (RP). The first sign of retinitis pigmentosa is difficulty seeing in low light (night blindness). As the condition gets worse, they develop tunnel vision (peripheral, or side, vision loss). Retinitis pigmentosa may lead to blindness.

Balance issues: Children with Type 1 Usher syndrome may have difficulty keeping their balance, so it may take them longer to learn how to walk.

Causes

Usher syndrome is an inherited disorder that happens when both biological parents carry one or more of the genetic mutations that cause Usher syndrome. Research shows that those mutations affect people in different ways. For example:

Hearing loss in Usher syndrome happens when genetic mutations affect nerve cells in the cochlea of your child’s inner ear so nerve cells don’t transmit sound as they should.

Retinitis pigmentosa happens when genes that make up retina cells mutate. That mutation affects your child’s retina’s light-sensing cells (rods and cones).

Risk factors

Inheriting one or more of the genetic mutations that cause Usher syndrome is the most significant factor:

If both biological parents carry the genetic mutation, there’s a 1 in 4 chance that their child will have the syndrome.

If a child receives one normal gene from one biological parent and a mutated gene from the other biological parent, that child will carry the genetic mutation that causes the syndrome but probably won’t have any symptoms.

Complications

The complications vary depending on the type of syndrome. For example, a baby with Type 1 Usher syndrome will have total hearing loss or severe hearing loss at birth. In this case, a healthcare provider may recommend cochlear implants so the baby can hear. But a baby with Type 2 Usher syndrome who has moderate hearing loss may be able to do well with hearing aids. Children who start to lose their vision as they get older will need support as they adapt to losing their ability to see.

Diagnosis

Diagnosis depends on the specific syndrome type. For example, if routine newborn hearing screening tests detect that your baby has hearing loss, your baby will have more tests to confirm the loss. A healthcare provider may recommend genetic counseling or order genetic tests to check for the genetic mutations that cause Usher syndrome.

If your child appears to have issues seeing or hearing, their pediatrician may refer you to specialists who’ll order tests, including:

Hearing tests: An ear, nose and throat specialist (otolaryngologist) and an audiologist will measure your child’s hearing. They use tests that check the ability to hear a variety of sounds and frequencies and examine your child’s ear.

Vision tests: An ophthalmologist will check your child’s vision. They’ll look for damage to the retina that’s common in people with retinitis pigmentosa. They can also perform tests that measure peripheral vision. And they can analyze visual symptoms that might result in balance problems.

Treatment

Healthcare providers will tailor treatment to your child’s situation. Treatments for Usher syndrome may include:

Cochlear implants: Often healthcare providers will recommend a cochlear implant for babies born with severe hearing loss.

Hearing aids: If your child has mild-to-moderate hearing loss, they may benefit from hearing aids or other hearing assistive technology. These can be especially useful if your child has Type 2 or 3 Usher syndrome and develops hearing issues as they grow up.

Vision aids: Your child’s provider may prescribe assistive devices to help your child manage their vision issues. For example, they may recommend eyeglasses with lenses that filter light or magnify objects.

Early intervention services: Some children with Usher syndrome may benefit by receiving early intervention services to help them manage vision, hearing and balance issues.

Type of Doctor Department : Ophthalmologists , audiologists or ENT specialists