What is Usher Syndrome?
Usher syndrome (Usher, USH) is the leading genetic cause of combined deafness and blindness.
There are 3 clinical types of Usher syndrome named USH1, USH2 and USH3, based on the severity and age of onset of deafness and blindness, and in some patients, vestibular areflexia. USH1, the most severe form, is characterized by congenital, bilateral, profound sensorineural hearing loss, vestibular areflexia, and adolescent-onset retinitis pigmentosa (RP). USH2 is the most frequent form characterized by congenital, bilateral sensorineural hearing loss that is mild to moderate in the low frequencies and severe to profound in the higher frequencies, intact vestibular responses, and RP that begins in the second-third decade of life. USH3 is characterized by postlingual, progressive sensorineural hearing loss, late-onset RP, and variable impairment of vestibular function. The RP is a progressive, bilateral, symmetric retinal degeneration that begins with night blindness and constricted visual fields (tunnel vision) and eventually includes decreased central visual acuity. The rate and degree of vision loss vary within and among families.
Usher syndrome was first described in 1858 by Albrecht von Gräfe. However, the syndrome was named after Charles Howard Usher, a Scottish Ophthalmologist, who described the syndrome in 1914 on 69 patients, in an article called “On the inheritance of Retinitis Pigmentosa, with notes of cases”.
Who is affected by Usher syndrome?
The incidence of Usher is estimated at 1:6000 - 20000 individuals worldwide. Approximately 3-6% of hearing impaired children have Usher. An estimated 10% of children born with congenital profound sensorineual hearing loss have Usher. Current reports indicate that Usher accounts for more than 50% of people who are both deaf and blind.
What causes Usher syndrome?
Usher is inherited in an autosomal recessive manner. Both males and females can inherit Usher when he or she receives a mutation from each parent.
How does Usher syndrome affect Louisiana?
Dr. Kloepfer and his colleagues first reported Usher syndrome in Louisiana Acadian patients in 1966. Because of founder affect, Usher type 1C is suggested to have a higher incidence in the Acadian population than the general American population. In addition, a few patients with Usher type 2 have been reported within the Acadian population.
Virtually all type 1 Usher syndrome in the Acadian populations of Louisiana and Canada are cause by a single mutation the USH1C gene.
Management of Usher syndrome patients
The key to management of patients with Usher syndrome is early diagnosis. Early diagnosis enables adapted educational and patient management options. While there is no definitive cure for USH, there are a lot of treatments, and many of these treatments are most successful when begun early in life. The program is specific to each patient, is multidisciplinary, and is tailored to individual patient needs depending on the severity of the symptoms.
The team comprises specialists in Otolaryngology, Ophthalmology, Genetics, Audiology and Nursing.
So what is in the future for patients with Usher syndrome?
Several advances have been made by Dr. Jennifer Lentz and her team at Louisiana State University Health Science Center. They have created a mouse model of Usher that contains the same mutation responsible for Acadian Usher. More recently, they have developed a drug and shown rescue of hearing and vestibular function in the Usher mice after a single treatment early in life. The study was published in Nature Medicine (Nature Medicine,2013 March, Vol 19 (3), Pages 345–350). Preclinical animal testing in underway in Dr. Lentz's research laboratory. While the treatment is a long way away from a clinical trial, it is a huge step in the right direction.
Resources for Healthcare Professionals:
Anita Jeyakumar, MD, FACS (Usher syndrome Medical Management in New Orleans)
Childrens Hospital New Orleans
200 Henry Clay
New Orleans, La 70118
National Institutes of Health
Resources for Patients and Families:
Cassondra Glausier (Education and Resources in Louisiana)
Coordinator of the Louisiana Deafblind Project
1900 Gravier Street, Box G6-2
New Orleans, La 70112
Jennifer Lentz, PhD (Current Research in Usher syndrome)
Assistant Professor in Otorhinolaryngology
Member of the Neuroscience Center of Excellence
2020 Gravier Street
New Orleans, La 70112
Coalition for Usher Syndrome Research (Online Educational Information and Registry)
2 Clock Tower Place, Suite 418
Maynard, MA 01754
Krista Vasi, Executive Director
For more information, click here.