Genetic localization of a new locus for recessive familial spastic paraparesis to 15q13-15.
OBJECTIVE
To characterize a new gene locus for familial spastic paraparesis (FSP).


BACKGROUND
FSP is a genetically heterogeneous group of upper motor neuron syndromes. It can be inherited as an autosomal dominant, autosomal recessive, or X-linked disorder. Four loci for autosomal dominant FSP have been genetically mapped, and two genes have been shown responsible for the X-linked type. In addition, two loci for autosomal recessive type have been reported and mapped to chromosomes 8q and 16q. The gene for the 16q locus has been characterized as a mitochondrial protein.


METHODS
Eight recessive FSP families from America and Europe were used for genetic linkage analysis. The known recessive loci (8q and 16q) and the X-linked loci (PLP and L1CAM genes) were screened through PCR amplification, followed by linkage analysis, single-strand conformational polymorphism, or both.


RESULTS
All the families except one revealed lack of linkage to the known loci for recessive and X-linked types of FSP. One of the eight families showed data consistent with linkage to the previously characterized 8q locus. Analysis of all the families for possible linkage to other candidate loci revealed significant positive lod scores for markers in chromosome 15q. The maximum multipoint combined lod score for the non-8q families was Z = 3.14 for markers D15S1007, D15S971, D15S118, and D15S1012, at a distance of 6.41 cM from the marker D15S1007, in between D15S971 and D15S118.


CONCLUSIONS
Our data suggest a new locus for recessive FSP linked to chromosome 15q, and that this may be the most common one.
Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, PA, USA.
F
F
Martínez Murillo
H
H
Kobayashi
E
E
Pegoraro
G
G
Galluzzi
G
G
Creel
C
C
Mariani
E
E
Farina
E
E
Ricci
G
G
Alfonso
R M
RM
Pauli
E P
EP
Hoffman
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D002874:Chromosome Mapping; D002884:Chromosomes, Human, Pair 15; D005260:Female; D005808:Genes, Recessive; D005819:Genetic Markers; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D018807:Polymorphism, Single-Stranded Conformational; D011647:Puerto Rico; D015419:Spastic Paraplegia, Hereditary / Q000235:genetics*; D014481:United States
D005819:Genetic Markers