Objectives: Hereditary spastic paraplegias (SPG) are a group of neurodegenerative disorders that
can be inherited as an autosomal recessive, dominant or X-linked recessive trait.
So far, up to 29 loci have been recognized, and 11 genes identified. SPG might be
pure, when paraplegia is the only manifestation, or complicated, when it is accompanied
by other symptoms, as dementia, peripheral neuropathy, retinitis pigmentosa and epilepsy.
SPG11 is one of the 15 known recessive forms of spastic paraplegias and it is characterized
by mental retardation and/or dementia and thin corpus callosum. In some families,
SPG11 is linked to 15q13–15, but its gene was not identified. SPG 11 has been reported
worldwide and might be one of the more common recessively inherited forms of SPG.
The purpose of this presentation is to report clinical, MRI and genetic data on new
observations on SPG11.
Methods: In the last two years, we evaluated 10 individuals, belonging to 7 families (3 of
then consanguineous and 2 with more than one affected sibling) with SPG11. MRI was
performed in at least one of the affected individual in each family. In consanguineous
or with multiple affected siblings families, a genetic analysis using polymorphic
markers for 15q13–15 was performed. Results: Clinical phenotype was quite similar and includes: 1. Onset in the 1st or 2nd decades
of life, with mental retardation or dementia; 2. Spastic paraplegia with onset at
2nd decade; 3. Clinical signs, as cerebellar ataxia, peripheral neuropathy, epilepsy
were variably present; 4. Brain MRI showed thin corpus callosum in all studied patients.
In pedigrees with multiple affected individuals, they share the same haplotype for
15q13–15; in consanguineous families, affected individuals are homozygous for this
same region.
Conclusion: Spastic paraplegia with thin corpus callosum is a distinct phenotype that might be
investigated in complicated SPG with recessive inheritance.
