Brittle Cornea Syndrome 1
Patient Information
Characteristics
Background and History
This disorder is a part of a complex of disorders known as Ehlers-Danlos syndrome (EDS) which has numerous subtypes, several of which have significant ocular abnormalities in addition to more general systemic manifestations. (Edvard Lauritz Ehlers was a Danish dermatologist and Henri-Alexandre Danlos a French dermatologist). It is an uncommon condition and most cases come from the Middle East. The mutations causing these syndromes results in abnormalities in connective tissue throughout the body.
Clinical Correlations
Brittle cornea syndrome is a subtype of Ehlers-Danlos type VI, designated VIB. The eye often appears bluish resulting from a thin, defective sclera (normally the white of the eye). The most serious aspect of this condition is the abnormally thin and often malformed cornea (the clear windshield of the eye) which is easily ruptured following relatively minor trauma. The cornea may also appear cloudy, especially after tears are healed. The skin is easily stretchable or hyperelastic. Joints are very flexible and can dislocate relatively easily as in other forms of EDS.
Genetics
Inheritance
This is an autosomal recessive disorder which requires that both parents, who are clinically normal, carry the mutation and pass it to their offspring. Parents are often related to each other.
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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