[Spinocerebellar ataxia type 7: clinical and molecular genetic analysis of a Mexican family].
BACKGROUND
Spinocerebellar ataxias (SCA) constitute a group of neurodegenerative diseases characterized by cerebellar disfunction alone or associated with other neurological anomalies. The combination of progressive cerebellar ataxia, macular pigment dystrophy, ophtalmoplegia, spasticity and an autosomal dominant pattern of transmission is characteristic of SCA 7. Genome wide linkage analysis mapped the defective gene to 3p12 13.


OBJECTIVE
To describe a Mexican family with SCA 7.


METHODS
We present a family pedigree of 13 individuals with ataxia and other neurologic findings in 3 generations. The evaluation consisted of a complete clinical and neurologic examination; neuropsychologic, neurophysiologic, ophthalmologic, neuroradiologic assessments and a molecular genetic study. The first 2 generations had a history of gait disturbance and visual loss. We objectively found a global cerebellar syndrome, pyramidal signs, visual impairment and ophtalmoparesis in variable grades in all members of the third generation All had progressive retinal degeneration, cerebellar, brainstem and hemispheric atrophy. We observed anticipation phenomena. Genetic analysis of the father of the third generation showed expansion of CAG triplet repeats at the SCA 7 gene.


CONCLUSIONS
The clinical and genetic findings confirmed the diagnosis of SCA 7, and this is the first report in a Mexican family.
Rolón Lacarriere
O
O
Departamento de Neurología Pediátricia, Centro Medico Nacional 20 de Noviembre del ISSSTE, Mexico DF, Mexico. oscarrolon@hotmail.com
Rasmussen Almaraz
A
A
Hernández Cruz
H
H
Carranza del Río
J
J
González Cruz
M
M
Gutiérrez Moctezuma
J
J
D000328:Adult; D000368:Aged; D000067719:Ataxin-7; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D005260:Female; D005799:Genes, Dominant; D006801:Humans; D008297:Male; D008800:Mexico; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000235:genetics*; D010375:Pedigree; D010641:Phenotype; D020754:Spinocerebellar Ataxias / Q000175:diagnosis / Q000235:genetics*; D019680:Trinucleotide Repeat Expansion
C000593829:ATXN7 protein, human; D000067719:Ataxin-7; D009419:Nerve Tissue Proteins