[Three patients of complicated form of autosomal recessive hereditary spastic paraplegia associated with hypoplasia of the corpus callosum].

We report three patients with slowly progressive spastic paraplegia and dementia; MRI on these patients revealed hypoplasia of the corpus callosum. The mode of inheritance was supposed to be autosomal recessive. Patient 1 (26-year-old man) is an elder brother of patient 2 (21-year-old man). Their parents are first cousins. Patient 3 (woman), a sporadic case, died of pneumonia at the age of 44. Their motor development after the birth was normal, but patient 3 was mildly mentally retarded. Gait disturbance due to spastic paraplegia developed at the age of nine (patient 2), fifteen (patient 1) and nineteen (patient 3), respectively. They also showed slowly progressive mental deterioration. Patient 1 has also suffered from mild amyotrophy and sensory disturbance in the distal part of the extremities since the age of 25. Patient 3 was bed-ridden at the middle of her thirty's because of generalized amyotrophy and sensory disturbance in addition to spastic quadriplegia and profound dementia. Their MRI reveal the thinning of the corpus callosum. We think the thinning must be hypoplasia of the corpus callosum, because the cerebrum showed normal appearance on MRI in patient 1 and patient 2. These clinical findings and imaging studies are essentially similar to those of the cases reported by Iwabuchi et al (1991). We propose autosomal recessive HSP associated hypoplasia of the corpus callosum as a new type of HSP.