Myopia and Deafness
Patient Information
Characteristics
Background and History
Near-sightedness (myopia) is the most common eye condition in the world. It may occur by itself but it is also a common trait in other heritable disorders.
This is a recently reported and rare inherited disorder. Nine patients in three families have been described.
Clinical Correlations
The near-sightedness is usually diagnosed in the first year of life. There is no information on progression of the myopia or its complications, but vision is usually good if corrected with glasses or contact lenses.
Marked hearing loss is likely present at birth and usually diagnosed before the age of 2 years. There is no evidence of developmental delay or learning difficulties.
Genetics
Inheritance
This is an autosomal recessive disorder which results from mutations in both members of a pair of genes. The parents, who each contribute one mutated gene, are clinically normal without hearing loss or near-sightedness. In such families, parents can expect on average that one out of four of their children will have this condition.
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
This disorder is present at birth. While parents and pediatricians often detect it based on the vision and hearing responses of infants, the precise diagnosis requires a gene test to confirm the presence of the altered (mutated) genes.
With the correction of myopia (glasses or contact lenses), and the use of hearing devices based on the recommendation of ophthalmologists and hearing specialists, these patients can live near-normal lives.
Printer Friendly Version: Ctrl/Cmd+P