Let’s start with a brief genetics lesson. Each of us has 23 pairs of chromosomes that carry our genetic code. One of each pair comes from the father, and the other comes from the mother. The first 22 pairs are called “autosomal” chromosomes, and the 23rd pair is the “sex chromosome,” which determines a person’s physical gender.
Several genetic diseases (caused by mutated genes) are more common among Ashkenazi (Eastern European) Jews. Carriers of recessive Jewish genetic diseases have one normal gene and one mutated gene; they show no sign of the related genetic disease and usually have no idea they are carriers. When two carriers each pass the same mutated gene to a child, the child will suffer from the disease.
One in two Ashkenazi Jews in the United States is a carrier of at least one of 38 Jewish genetic diseases. That’s why the Jewish Genetics Disease Center of Phoenix strongly encourages all couples who plan to have children to take advantage of their affordable genetic testing and counseling. Pre-pregnancy screening allows families to know about genetic obstacles, and counseling gives them information about their options to deal with those obstacles.
Robyn and Michael Goldberg went through basic genetic testing before having their children, Liora (now 6), and Asher, (now 2). When no red flags were raised, the couple proceeded to build their clan. Liora was born healthy. But when Asher was born, he didn’t pass the newborn hearing test. The hospital audiologist advised Robyn “not to worry. He probably just has some fluid in his ears. We’ll retest him tomorrow.” When Asher didn’t pass the second screening, Robyn and Michael began to have some concerns.
Further screening at eight weeks at Phoenix Children’s Hospital showed severe hearing loss, but the couple was still hopeful that Asher’s hearing might improve. When Asher didn’t respond to hearing aids, his parents moved ahead with audio brain response and MRI tests to rule out anything more serious. They learned Asher had a Connexin 26 mutation found on the GJB2 gene. This mutation is the most common cause of congenital sensorineural hearing loss.
Connexin 26 mutations are genetically transmitted from parent to child in what’s known as a “recessive manner.” So, in order for Asher to have inherited this condition, both Robyn and Michael had to be recessive carriers of the mutated gene.
The only way to screen for a Connexin 26 mutation is to look for it specifically; it is not part of the JGD screening panel.
“I’ve ordered the Connexin 26 test before when I’ve had hearing impaired parents who requested it,” says Dr. Mark Gettleman, M.D., F.A.A.P. He adds, “80% of hereditary deafness is due to a Connexin 26 mutation. But if you have no history of deafness, there’s no real reason to get this test.”
Asher’s inability to hear affected his speech and language, as well.
“Finding out what it was actually gave us a little peace,” reflects Michael.
Robyn adds, “Learning that is was only hearing loss was a relief. In fact, the doctors kept telling us that it was the ‘best kind of hearing loss.’ ”
One of the most effective treatments for Asher’s kind of deafness is cochlear implants, so Robyn and Michael found a surgeon and proceeded to ready their 1-year-old for the delicate surgical procedure.
In January of 2014, Asher received double cochlear implants, which have enabled him to hear through magnetically connected processors that capture sounds that are then converted into brain signals Asher can hear. He doesn’t hear voices like regular hearing people might. “It’s more like a bionic ear,” explains Robyn.
One month after the surgery, the family went in to have the processors switched on. “The moment Asher heard sound was dramatic,” Michael says. “He jolted up and then buried his head into me.” Over the next five weeks the doctors slowly increased the volume to give Asher’s brain time to adapt to the new sensory input. “It was a way to ‘ease the light in,’ ” says Robyn, recounting the incredible process. The cochlear implant procedure is most successful when done within the first few years of life, before the brain starts to lose elasticity. Robyn and Michael were hesitant at first, because there are so many audiological advancements being made in medicine these days. They hated to take any action that might rule out future procedures. But the family chose to go forward because, in Robyn’s words, “We couldn’t wait for the future of medicine. He needs this now.”
Asher works diligently with a speech therapist. Robyn says, “His articulation needs work. … But watching Asher play animatedly, I have no trouble understanding when he says ‘momma’ or points to his adored sister and chirps ‘Liora.’ I can even understand when he gleefully points to the Mickey Mouse Skinets (stickers) on his external processors. He also sings the alphabet song and does a fine rendition of ‘Happy Birthday.’
“His very first word was Murphy,” the name of their beloved pup, his mom sheepishly reveals. She adds that “Murphy” was also her daughter’s first word.
The Goldbergs have shared their story across the nation to help educate parents about genetic testing and the importance of knowing your options. For example, if both parents are carriers of the same disease, there is a one in four chance with each pregnancy that their child will be born affected with that disease, and a two in four chance that their child will be a carrier of that disease. Carrier couples may choose in-vitro fertilization with pre-implantation genetic diagnosis. They can use egg or sperm from a screened non-carrier donor, opt for adoption, choose not to have children or even decide not to marry. But having the test allows couples to make informed decisions and better steer the course of their family’s journey.
Biology and Jewish history explain why the Ashkenazi population has such high carrier rates. During the large diaspora following the destruction of the second Temple, the incidence of the mutated genes in the Ashkenazi population was increased by repeated cycles of that population expanding and then shrinking dramatically several times over 2,000 years. Persecution reduced the Ashkenazi population frequently. If one person had the changed gene in the original population and 90% were killed, then if that one person survived, there was now a 10% chance of the changed gene being in the population.
The current Ashkenazi test panel used by the Jewish Genetic Disease Center includes 18 diseases. Different genetic diseases disproportionately affect Sephardi/Mizrahi Jews (those originating from North Africa and Mediterranean countries).
For more information on genetic testing and counseling, visit jewishgeneticsphx.org.
