The cornea is the normally clear windshield at the front of the eye. A number of gene mutations result in the deposition of abnormal material in this tissue which causes cloudiness and interferes with vision.
Macular corneal dystrophy may have its onset in infancy but sometimes is not diagnosed until the second or third decade of life. Cells in the deeper layers of the cornea accumulate abnormal material creating a general cloudiness which is progressive. The impairment of vision can be severe by mid-life and may require a corneal transplant. This is not a systemic disease although abnormal levels of a sulfur containing compound have been detected in the blood.
This is an autosomal recessive disorder which requires the inheritance of two copies, one from each parent, of the mutation. The family pattern of affected individuals is, therefore, horizontal since the disorder is not passed from an affected parent to a child.
It is often possible to make a tentative diagnosis by seeing cloudiness in the corneas (this is a bilateral disease) but the exact diagnosis requires an ophthalmological examination since several corneal dystrophies appear superficially similar.