Usher syndrome Type III is the rarest form of genetic disorder. As a genetic disease, there are tests available to diagnose this illness, including prenatal tests.
What Is Usher Syndrome?
Usher syndrome is a genetic disease that affects hearing and vision. It also goes by the names Graefe-Usher syndrome, Deafness-retinitis pigmentosa syndrome, and dystrophia retinae pigmentosa-dysostosis syndrome. It is a progressive disease so that sufferers at first experience mild symptoms such as difficulty being able to see at night. As the disease worsens, individuals eventually develop blind spots and tunnel vision. While those who have it retain some vision, most patients become completely deaf.
Types of Usher Syndrome
There are three main types of Usher. Type I affects individuals throughout their whole lives. Those with Type I are born deaf or completely lose their hearing within their first year of life and they start losing their vision in childhood. Type II patients are also born deaf or experience complete hearing loss during the first year. However, the onset of vision loss starts later, usually around adolescence. Those with Type III experience symptoms later in life. Unlike Type I or Type II, Type III infants are able to hear and do not experience hearing loss until they approach adolescence. Vision loss begins to occur around the same time.
Rarity of Type III
Overall, this is a rare disease. On average, it occurs in just 4 out of 100,000 people. However, because it is a genetic disease, it occurs with a higher rate in certain populations such as eastern and central European Jewish ethnicity. Even among patients, Type III is rare. The sole exception lies within the Finnish population where 40 percent of patients have Type III.
Usher Syndrome Type III Genes
Several genes produce Usher Syndrome, but Clarin One, or CLRN1 is the only gene identified as being responsible for the Type III disease. This gene plays a crucial role in the development of vision, hearing, and balance. The disease requires at least two mutations; one of the CLRN1 gene and another gene yet to be identified.
Genetic Tests
Since the CLRN1 gene mutation is a hallmark of Usher syndrome Type III, genetic testing is available. Carrier tests can determine if someone has the potential to pass along Usher syndrome to their offspring. Prenatal tests can determine if a child will be born with the disease.
Sometimes it may seem tempting to avoid these tests and hope for the best, but doing so puts your offspring at more risk. If you know that a genetic disease is a high possibility, you can prepare ahead of time, and know what to do if it happens. You could have doctors ready to help you, and information on hand. Burying your head in the sand is rarely the right thing to do in any situation, and when it comes to genetic testing for potential diseases one should definitely consider the many up-sides.
You may visit the following URL to learn more about this topic:
By Robert Fogarty
Aucun commentaire:
Enregistrer un commentaire