Branchio-Oto-Renal Syndrome - The Cain Foundation

The following information has been put together and researched by myself and overlooked by Head, Dept of Nephrology, Dr. Andrew Rosenberg and Dr. William Kimberling of Omaha, Nebraska, Boys Town - Genetics Researcher and Professor for Biomedical Sciences. Most of the information gathered here was taken from the BOYS TOWN Website.

Branchio - oto- renal Syndrome (BOR), formerly known as the Ear pits, Deafness Syndrome is a genetic disorder that includes malformations of the outer, middle and or inner ear, cysts/fistulas in the neck, hearing loss and malformations of the kidneys. There are varying combinations of these problems in differing degrees. BOR has an autosomal dominant mode of inheritance. This means that for an individual who has BOR, there is 50% chance of passing on the gene with each pregnancy. Nonpenetrance (having no sign or symptom of the disorder despite having the gene) is very unusual for BOR. However, variable expression (variation in the manner and severity with which the gene is expressed among and within families) is very common, and an individual with the gene may have only one or two of the three clinical aspects of the syndrome. BOR syndrome has an estimated general prevalence of 1:40,000 and occurs in 2% of the profoundly deaf.

I was told by our Specialists that most cases treated here in Sydney, Australia were spontaneously born (de novo mutation) with this Syndrome rather than it being passed on from a parent who carries the gene.

The B in BOR refers to the branchial arches which are the area of the embryo that develops into the outer and middle ear, the neck and the lower part of the individuals face. There are several types of malformations of the branchial arches in BOR including cupping of the outer ear, ear pits which are very small holes (about the size of the hole in a pierced ear) in front of or on the outer ear, tags of skin in front of the ear and cysts or fistulas on the neck.

OTO refers to the ear and in particular the hearing loss that is part of the syndrome. The hearing loss can be sensorineural, conductive or mixed. It can be stable or progressive and the severity can range from mild to profound. Most people with BOR have some degree of hearing loss. Malformations of the ears can include cupping of the outer ear, very small holes in front of the outer ear and tags of skin in front of the ear.

RENAL refers to the kidneys which can be abnormal in size, shape, structure and or complete absence. They may be smaller than usual or have a malformation that does not interfere with function or cause any symptoms. However, the kidney malformation may be severe enough to predispose the individual to kidney disease, or a baby may be born without kidneys which would be incompatible with life. The BOR syndrome is an infrequent but well described entity that combines early � onset renal failure and deafness together with branchial clefts and preauricular pits. Renal agenesis and dysplasia are the causes of ESRD in these individuals. Other renal abnormalities include bifid kidneys with double ureters, vesico-ureteric reflux and pelvi-ureteric stenoses. The BOR Syndrome should be included in the differential diagnosis of deafness and chronic renal failure in childhood and adolescence.

My first born son, Harrison presented with cupping of the outer ear, 2 ear pits in front of the outer ear and 2 fistulas/branchial sinuses on the neck. We have since had the ear pits and fistulas surgically removed at 6 months of age. Harrison has had his hearing tested regularly and it appears to be normal. His next test is at the age of 3 years. Harrison�s major symptoms are abnormal hypoplastic kidneys with the likelihood of progressive polyuric � type renal failure and eventual end stage renal failure.

In some families with BOR there are individuals who have blocked tear ducts which interfere with the normal flow of tears and have to be opened surgically. There have also been reports of individuals with salivary tissue in their ducts which causes them to have tearing when they eat.

The BOR gene has been mapped to chromosome 8. Research continues to actually identify the gene. It is hoped that eventually we will be able to determine how the gene causes the problems associated with BOR which may lead to treatment or prevention of the progression of those problems.