Oguchi Disease, Type 1
Patient Information
Characteristics
Background and History
Chuta Oguchi, a Japanese ophthalmologist, first described this condition in 1907. It has its onset at birth, causing night blindness, and is not progressive. Two types have been described.
Clinical Correlations
Oguchi disease is a nonprogressive disorder that causes night blindness. It is present at birth. Daytime vision, color vision, and side vision are all normal. It is a unique condition in which the color of the retina in the back of the eye is golden or gray-white in lighted conditions but this color disappears in dark situations. There is no associated systemic disease.
Genetics
Inheritance
This is an autosomal recessive disorder requiring the presence of two mutations, one inherited from each parent.
Pedigree
Autosomal recessive
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
Diagnosis and Prognosis
The diagnosis is usually made by an ophthalmologist based upon the symptoms, color of the retina, and the results of an electroretinogram (ERG). The prognosis for vision in daylight is excellent but night blindness is permanent and no treatment is available. No other organs are affected.
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