Cranial Dysinnervation Disorders with Strabismus and Arthrogryposis
Patient Information
Characteristics
Background and History
This condition includes prominent eye movement problems and joint stiffness. It is a category of disease that includes several disorders.
Clinical Correlations
Most patients have droopy eyelids (ptosis) and an inability to move the eyes properly. There may also be some dysfunction and anatomic changes of the retina. The arms and wrists do not have the full range of motion. The creases on the palms and of the finger joints are sometimes absent. The spine is often stiff. Lack of mobility in the rib cage can cause difficulty in breathing. The roof of the mouth (palate) is sometimes highly arched and may be incompletely formed (cleft palate). Many patients are short in stature.
Genetics
Inheritance
Mutations in several genes seem to be responsible but the clinical features are highly variable, creating diagnostic challenges. This condition may be inherited as an autosomal recessive disorder with a 25% risk to additional offspring, or it may be caused by a single mutation in which case it is inherited as an autosomal dominant disorder with a 50% risk of recurrence.
Pedigree
Autosomal dominant
Autosomal dominant disorders require only one mutation for the disease to be expressed. Since an affected parent has two chromosomes, only one of which has the mutant gene, parents can expect that half (50%) of their children will receive that one and inherit the disease. It is common for individuals that inherit the mutation, however, to not have evidence of the disease (nonpenetrance).
Autosomal dominant inheritance leads to a vertical pattern of transmission
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
Pediatricians, ophthalmologists, and orthopedists may all be involved in the diagnosis and care of patients with some variant of this condition. There is no treatment for the overall disorder but selective surgery for specific problems might be helpful. Low vision aids might be helpful in some individuals with decreased vision.
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