There are 7 known families with children who have been diagnosed with KCNK9 Imprinting Syndrome. The original family that was studied (2008) in northern Israel, to find this mutation is believed to have approximately 23 family members affected. The other cases that we know of are of de novo origin. There are three children in the United States, and one each in Brazil, Singapore, & Poland. The original Arab-Israeli family has a large age range with some grown children. The new cases, including our son, are all under the age of four. All were diagnosed via Exome Sequencing and have the same amino acid change (G236R). Our understading is that this syndrome does not appear to be a degenerative or life-shortening disease.
Like with any syndrome there is variability of disease and each child is affected differently. Some are impacted far more then others. Most of the children are diagnosed with mild to severe low muscle tone (hypotonia). There are also varying degrees of cognitive impairment. The milestones of the large Arab-Israeli family were not documented and some efforts are being made to get that data. Three of our kids had a unusually narrow, v-shaped cleft palate. Several children have a seizure history. Some of the children suffer from scoliosis. All of the children had feeding difficulties in infancy. Most required a feeding tube for at least 5 months. Others like Preston still require a gastrostomy tube. The feeding issues in the large family were said to have resolved by puberty. All of our children are delayed in gross motor skills. Speech is another area that is also universally delayed. 2 of the 5 children are talking now after the age of 3.
The geneticists that have been in touch with the Arab-Israelis were able to share some information. A few of these individuals are in their teen years. We were told that they all walk and talk. The mental status is extremely variable from normal, to the mild, to the moderate affected spectrum. Their main medical problems were related to reduced muscle tone and slim build. As far as the doctors know none of them had early intervention services. All of the older children appeared to be walking by the age of 6. One of the older boys was able to attend and graduate through a typical high school.
All of our children are very social and love attention and to be around others. They love music and singing. They are all receiving early intervention services and various therapies. Preston receives speech therapy, feeding therapy, occupational therapy, physical therapy, 8 hours of early intervention, with augmentative communication therapy and behavior therapy pending approval.