Spastic Paraplegia 15
Patient Information
Characteristics
Background and History
Spastic paraplegia is a neurological disorder with prominent symptoms of stiffness in the arms and legs. There are numerous types, most of them hereditary, distinguished from each other by the types of symptoms present depending on what brain structures are involved. Virtually all are progressive disorders with variable ages of onset.
Clinical Correlations
Type 15 spastic paraplegia is relatively rare and the complete clinical characteristics are probably not fully defined. Onset of symptoms is usually in the second decade of life, often beginning with a tremor in the hands and some unsteadiness. The muscles in arms and especially in the legs become stiff and speech becomes slurred. Some mental impairment is evident early but there is no evidence that this is progressive in nature. The small muscles in the hands and feet may appear wasted. Epilepsy and hearing deficits have been described. The retina line the inside of the eye often has some unusual yellowish spots but vision is minimally impaired if at all. Little is known about the progression of this disease.
Genetics
Inheritance
This is an autosomal recessive disorder caused by mutations in a gene. The parents, often related to each other, carry a single copy of the mutation and are clinically normal. However, such parents can expect on average that 1 in 4 of their children will inherit 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
The diagnosis is usually made by a neurologist in consultation with an ophthalmologist. No treatment is known nor is there information on longevity. Physical therapy may be helpful to prolong mobility.
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