Brittle Cornea Syndrome 2
Patient Information
Characteristics
Background and History
Fragile and brittle corneas may occur in isolation but may also be part of syndromes. It is an uncommon condition most commonly found among Middle Eastern populations. The genetic defect may also affect other areas of the body such as the skin, joints and bone development.
Clinical Correlations
The corneas (window of the eye) are extremely fragile and can rupture with minimal trauma. The tissue is abnormally thin making repair difficult if not impossible. The cornea is also misshapen in many patients producing high nearsightedness. The generalized coating of the eye (sclera) is abnormally thin as well and often appears bluish.
The skin is lax and bruises easily. Joints such as the shoulder dislocate easily and congenital dislocation of the hips is not uncommon. Heart valves may be ‘floppy’. The hard palate is often highly arched and the sternum of the chest is concave in structure.
Genetics
Inheritance
This is an autosomal recessive disorder that requires that each parent contribute one of the two mutations required. The parents, who may have mild manifestations of the disorder, can expect that one in four of their children will inherit the full spectrum of this disorder.
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
Diagnosis generally requires a multidisciplinary team of specialists. Your eye doctor is a primary member because of the ocular abnormalities that can suggest this syndrome (there are numerous other corneal disorders that can look similar). Protective eyewear should be used since the cornea may rupture with little trauma. While this can often be repaired it can also lead to catastrophic results. Other tissues such as skin and joints usually do not require treatment except acutely in cases with acute joint dislocations.
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