Search

Objective: To identify of the gene responsible for the onset of spinocerebellar ataxia type 16 (SCA16)., Methods: We reanalyzed the linkage of the original Japanese pedigree using updated information, including three additional subjects. We then screened all exons located in the critical region., Results: We reassigned the locus of SCA16 to 3p26.2-pter (maximum logarithm-of-odds score = 5.177) and identified only one point mutation (4,256C-->T) in the 3' untranslated region of the contactin 4 gene (CNTN4) on chromosome 3p26.2-26.3, which cosegregated with the disease. This mutation was not detected in 520 control subjects; moreover, we revised the phenotype of SCA16 from pure to complicated SCA., Conclusion: The contactin 4 gene (CNTN4) is associated with cerebellar degeneration in spinocerebellar ataxia type 16. Additional studies are necessary to prove 4,256C-->T to be a causative mutation.

Objective: To characterize a distinct form of autosomal dominant cerebellar ataxia (ADCA) clinically and genetically., Background: ADCAs are a clinically, pathologically, and genetically heterogeneous group of neurodegenerative disorders. Nine responsible genes have been identified for SCA-1, -2, -3, -6, -7, -8, -10, and -12 and dentatorubral-pallidoluysian atrophy (DRPLA). Loci for SCA-4, -5, -11, -13, and -14 have been mapped., Methods: The authors studied a four-generation Japanese family with ADCA. The 19 members were enrolled in this study. The authors performed the mutation analysis by PCR and a genome-wide linkage analysis., Results: Nine members (five men and four women) were affected. The ages at onset ranged from 20 to 66 years. All affected members showed pure cerebellar ataxia, and three patients also had head tremor. Head MRI demonstrated cerebellar atrophy without brain stem involvement. The mutation analysis by PCR excluded diagnoses of SCA-1, -2, -3, -6, -7, -8, and -12 and DRPLA. The linkage analysis suggested linkage to a locus on chromosome 8q22.1-24.1, with the highest two-point lod score at D8S1804 (Z = 3.06 at theta = 0.0). The flanking markers D8S270 and D8S1720 defined a candidate region of an approximately 37.6-cM interval. This candidate region was different from the loci for SCA-4, -5, -10, -11, -13, and -14., Conclusion: The family studied had a genetically novel type of SCA (SCA-16).

The proband, a 53-year-old man, developed progressive spinal and bulbar muscular atrophy and gynecomastia at the age of 50. His father had weakness of lower limbs, and his son had a nasal voice, ocular movement abnormalities, and gynecomastia, whereas two of the proband's brothers showed either gynecomastia or tongue fasciculations. None of the patients showed any expansion of CAG repeat in the androgen receptor gene or any hormonal abnormality. Thus, this family is affected by a form of autosomal dominant spinal and bulbar muscular atrophy with gynecomastia.

Objective: To clarify the function of adrenoleukodystrophy protein (ALDP) using our ALDP-deficient mice established by gene targeting., Background: X-linked adrenoleukodystrophy (ALD) is characterized biochemically by the accumulation of very long-chain fatty acids (VLCFA) in tissues and body fluids, and is caused by impairment of peroxisomal beta-oxidation. In ALD, very long-chain acyl-coenzyme A synthetase (VLACS), which is necessary for peroxisomal beta-oxidation, does not function., Methods: The ALDP-deficient mice and C57BL/6J mice were used. VLACS or ALDP were transiently expressed by lipofection in murine fibroblasts, and VLCFA beta-oxidation was assayed. Liver peroxisomes were purified by sequential centrifugations and a Nycodenz gradient centrifugation. The peroxisomal localization of VLACS was compared between the mutant and control mice using a Western blot analysis., Results: Impairment of VLCFA beta-oxidation in ALDP-deficient fibroblasts was not corrected by the additional expression of VLACS alone but was by the coexpression of VLACS and ALDP. Although the tissue-specific expression of VLACS was similar in ALDP-deficient and normal mice, peroxisomal VLACS was clearly lower in ALDP-deficient than in normal mice., Conclusions: ALDP plays a role in the peroxisomal localization of VLACS, and VLACS does not function unless localized in the peroxisome.