Large deletion mutation of SPAST in a multi-generation family from Sardinia.

BACKGROUND AND PURPOSE: The hereditary spastic paraplegias (HSP) are characterized by progressive spasticity of the lower limbs, mostly inherited as an autosomal dominant trait. Analyses of large HSP pedigrees could help to better characterize the phenotype due to a single causative mutation. Patients in a seven-generation kindred carrying a large deletion in SPAST/SPG4 are described. METHODS: Individuals originating from Sardinia were clinically and genetically studied. RESULTS: Sixty-seven subjects carried a heterozygous deletion encompassing exons 2-17 of SPAST. Fifty patients (53.2 ± 15.4 years) presented a pure form of spastic paraparesis characterized by mild impairment and slow progression. Most patients showed spasticity, increased tendon reflexes in the lower limbs and Babinski sign, whilst weakness was rarely detected and urinary disturbances occasionally reported. Amongst the 17 asymptomatic carriers of the mutation, minimal neurological signs were detected in 11 cases. CONCLUSIONS: A focus on spasticity, increased tendon reflexes and Babinski sign, more than on weakness, could help clinicians to promote early diagnosis in asymptomatic carriers of SPAST deletions.

Bridging Over the Troubled Heterogeneity of SPG-Related Pathologies: Mechanisms Unite What Genetics Divide.

The hereditary spastic paraplegias (HSP) are characterized by spastic gait with weakness in the legs and additional neurological or extra-neurological signs in "complicated" forms. The past two decades have witnessed major advances in our understanding of their molecular bases with the identification of a plethora of loci and the cloning of several SPG genes. Combined genetic and clinical information has permitted a modern, molecularly-driven classification and an improved diagnosis, with several new data on the possible disease mechanisms. Further heterogeneity will rapidly emerge with the diffusion of next-generation sequencing platforms and, under the shadow of common themes in the pathogenesis, new therapeutic options will likely emerge for a great number of patients.