Roll the Dice

Off and on through the years, I've been asked, "What are the odds of getting Usher syndrome (US)?" or "What is the prevalence of US?"

According to Boys Town (scroll down the webpage to find US in the link provided), the prevalence of US is 3½ out every 100.000 people. About 10% of children with sensorineural hearing loss have US.

NIDCD says: About 3-6% of deaf children and an additional 3-6% of hard-of-hearing children have US. It also states that about 4 out of 100.000 babies born in the USA have US.

From the WrongDiagnosis website: There are about 16.000 Americans living with US. The rate is about 1 in 17,000 (0.01%).

There are about 300 million Americans living in the USA today. The 16,000 Americans affected by US is a small number by comparison. US is a very rare disorder.

US is an autosomal recessive disorder. (This link has an excellent diagram explaining the inheritance pattern.) Both parents must have the gene in order to pass it down to the offspring. It is in the genetic makeup much like how the color of our eyes and hair is decided. One "brown eye" gene is taken from each parent in order for a child to get brown eyes.

-There is a 25% (one in four) chance of the child NOT getting either US gene. (Child is asymptomatic and is not a carrier).

-There is a 50% chance that the child gets one gene and becomes a carrier (asymptomatic, but may pass it on to his/her child only if partner has the gene).

-There is a 25% chance that the child gets an US gene from each parent. The child has US and is a carrier, too. (Because my partner did not have the US gene, my children are not affected, but they are carriers because I have it.)

Looking over the prevalence and incidence of US, it makes me wonder how come I am not so "lucky" winning the (lottery) jackpot?