OMIM ID:
Bornholm Eye Disease
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
This is primarily a disorder of high myopia but with additional features. The optic nerve head is moderately hypoplastic and RPE throughout the posterior pole is said to be thinner than normal. The males also have deuteranopia of a stationary nature and the disorder can also be considered a form of stationary cone dysfunction. Photophobia and nystagmus are not present. The ERG demonstrates reduced flicker function with abnormal photopic responses. Myopia is likely congenital as it has been found in children from 1.5-5 years of age.
The original families reported with this disorder originated on the Danish island of Bornholm from which the eponym is derived. However, a subsequent American family of Danish descent from nearby islands was found but the males were protanopes. All affected males had a temporal conus of the optic nerve as well as thinning of the RPE in the posterior pole. Visual acuity ranged from 20/20 to 20/40 with myopia of minus 10-18 diopters. No macular disease was visible, no vitreous changes were seen, and none of the subjects had a retinal detachment. There was no evidence of progression in clinical signs over a period of 5 years. The ERG showed normal scotopic rod function but cone responses were abnormal. All carrier females and unaffected individuals had normal ERGs and color vision.
Systemic Features
No systemic disease has been associated with this disorder.
Genetics
Inheritance
This is an X-linked disorder that maps to Xq28 but no gene mutation has been identified. A form of X-linked high myopia (MYP1) (310460) maps to the same region.
Pedigree
X-linked recessive, carrier mother
X-linked disorders are caused by a mutation on the X chromosome and both sexes can pass this to their children. If the mutation is in a recessive gene and carried by the mother, she usually does not have the disease since the normal X chromosome without the mutation neutralizes the mutation in the abnormal X chromosome. However, half her sons will inherit the mutation-containing X chromosome and therefore have the X-linked disease. Half the daughters will inherit the mutation-bearing X chromosome and are usuallly healthy 'carriers'.
X-linked disorders are caused by a mutation on the X chromosome and both sexes can pass this to their children. If the mutation is in a recessive gene and carried by the mother, she usually does not have the disease since the normal X chromosome without the mutation neutralizes the mutation in the abnormal X chromosome. However, half her sons will inherit the mutation-containing X chromosome and therefore have the X-linked disease. Half the daughters will inherit the mutation-bearing X chromosome and are usuallly healthy 'carriers'.
X-linked recessive, father affected
X-linked disorders are caused by a mutation on the X chromosome and both sexes can pass this to their children. If the mutation is in a recessive gene and carried by the father, he has the disease since his only X chromosome is mutant and he has no normal X to blunt the effects of the abnormal gene. His sons only receive his Y chromosome and thus are all normal. However, all his daughters receive his one and only X chromosome and will be healthy 'carriers'. Thus such males will have no affected children but half their grandsons from those daughters will have the same disease as he does.
X-linked disorders are caused by a mutation on the X chromosome and both sexes can pass this to their children. If the mutation is in a recessive gene and carried by the father, he has the disease since his only X chromosome is mutant and he has no normal X to blunt the effects of the abnormal gene. His sons only receive his Y chromosome and thus are all normal. However, all his daughters receive his one and only X chromosome and will be healthy 'carriers'. Thus such males will have no affected children but half their grandsons from those daughters will have the same disease as he does.