Usher Syndrome is a rare genetic ailment in children that affects both hearing and vision. Also termed as Hallgren Syndrome or Usher-Hallgren Syndrome, it is characterised by hampered structure and functioning of the inner ear membranes, auditory nerves, as well as the light-sensitive layer of the eye – the retina. These factors invariably result in both loss of hearing and obstructed vision in the afflicted child.
This condition is named after the recognised Scottish ophthalmologist Charles Usher, who was the first physician to describe the inherited nature and pathology of the disorder in 1914. However, it was the renowned German ophthalmologist Friedrich Wilhelm Ernst Albrecht Von Grafe who initially outlined the signs and symptoms of this genetic disorder in the year 1858. He was even widely regarded for spearheading the field of modern ophthalmology with his significant contributions to the branch of medicine.
Types Of Usher Syndrome:
Usher syndrome usually manifests with deafness in babies right from birth, while the instance of impaired eyesight arises during early childhood years or sometimes in adolescence. Medical experts, doctors and research scientists have identified three categories of Usher syndrome based on the severity of ear and eye malfunctions as well as how rapidly the ailment advances in the affected child.
Type 1 Usher Syndrome:
Newborns with type 1 Usher syndrome are born with a near-total lack of hearing and also display issues with balance owing to inner ear abnormalities, such as learning to sit and walk much later than other normal, healthy kids.
The visual accuracy of the eyes begins to fail before reaching the age of 10 years, initially showcasing night blindness which then progresses to total vision loss.
Type 2 Usher Syndrome:
The intensity of hearing loss at birth is slightly lesser in this form of the ailment than in Type 1 Usher Syndrome. The children also do not face any difficulties with bodily balance and inner ear complications.
Eyesight is affected at night only in teenage years in affected children, with a higher degree of ocular problems developing later on but not leading to total vision loss.
Type 3 Usher Syndrome:
In Type 3 Usher Syndrome, babies are born with normal hearing and vision, unlike in Type 1 and Type 2 variants of this gene-related illness.
Problems with auditory capabilities, eyesight and inner ear balance appear only in teenage years, gradually worsening by young adulthood to middle age.
Usher Syndrome is a genetic condition that is passed on to children from their parents. When both parents carry a defective mutated gene which the baby inherits at birth, it induces Usher Syndrome. This seldom occurring malady can develop in male and female offspring but happens only when the newborn acquires both the faulty genes – one from each parent.
The defining indications of Usher Syndrome are problems with hearing and a gradual decline in eyesight in the afflicted baby. In some cases, the child also experiences issues with body balance, being unable to sit erect, stand or walk steadily in early childhood.
The genetic mutations associated with Usher syndrome hamper the structure and functioning of the rod and cone cells in the retina – a condition known as retinitis pigmentosa.
Hearing abilities are impaired in children with Usher syndrome owing to genetic aberrations that impede the operations of the auditory nerves in the cochlea – a winding assembly in the inner ear that relays sound impulses to the brain.
The healthcare professional conducts a hearing test or audiometry test in children born with Usher syndrome. This is done at birth as well as over the early years of childhood, to assess the indications of hearing loss. This is followed up with audiology evaluations, that determine how loud a sound source must be for the affected child to be able to hear it.
The doctor also performs a visual field test to determine the peripheral vision abilities of the child, besides examining the retina thoroughly. A procedure known as electroretinogram (ERG) is also done to look for signs of retinitis pigmentosa and study the functioning of the retina. The physician does an electronystagmogram (ENG) protocol as well, to investigate if any involuntary eye movements are displayed by the child which helps spot inner ear balance issues.
Usher Syndrome is an inherited genetic ailment that does not have any cure. Treatment for the condition is based on identifying the type of Usher syndrome in the affected child and assisting them with hearing and eyesight problems to ensure improved quality of life.
The affected child is provided with devices such as hearing aids, cochlear implants to aid in sensing auditory impulses and listening to sounds. As the illness progresses to complete hearing loss and total blindness, sign language and braille techniques are taught to the patient.