Novel deletion of SPAST in a Chinese family with hereditary spastic paraplegia

<p><b>INTRODUCTION</b>Hereditary spastic paraplegia (HSP) belongs to a large, heterogeneous group of progressive neurodegenerative diseases characterised by progressive lower extremity weakness and spasticity, which is caused by developmental failure or degeneration of motor axons in the corticospinal tract. Classical genetic studies have identified at least 46 genetic loci responsible for HSP.</p><p><b>METHODS</b>A genetic study was conducted on a four-generation Chinese family with autosomal dominant HSP. The SPAST gene was investigated using linkage analysis and direct sequencing. Findings were compared with unaffected family members and 50 normal, unaffected individuals who were matched for geographical ancestry.</p><p><b>RESULTS</b>We identified a novel 14-bp heterozygous deletion that induced a frameshift mutation in exon 15 of SPAST (SPG4). This mutation is predicted to have functional impact and found to cosegregate with the disease phenotype.</p><p><b>CONCLUSION</b>Our results have expanded the mutation spectrum of the SPAST gene. These findings could help clinicians provide prenatal diagnosis of affected foetuses in families with a known history of such neurodegenerative diseases.</p>

Human SNF2L Gene Is Regulated Constitutively and Inducibly in Neural Cells via a cAMP-Response Element

PURPOSE: SNF2L belongs to Imitation Switch family and plays an essential role in neural tissues and gonads. In our previous studies, we have demonstrated that the basal transcription of human SNF2L gene is regulated by two cis-elements, cAMP response element (CRE)- and Sp1-binding sites. Recent studies suggested that cyclic adenosine monophosphate (cAMP) stimulation significantly up-regulated SNF2L expression in ovarian granulose cells. These data suggested that protein kinase-mediated signal pathways might also regulate SNF2L expression in neural cells. We therefore investigated the effects of agents that activate protein kinases A on SNF2L gene expression in neural cells. MATERIALS AND METHODS: To increase intracellular cAMP levels, all neural cells were treated with forskolin and dbcAMP, two cAMP response activators. We exmined the effects of cAMP on the promoter activity of human SNF2L gene by luciferase reporter gene assays, and further examined the effects of cAMP on endogenous SNF2L mRNA levels by qPCR. RESULTS: Transient expression of a luciferase fusion gene under the control of the SNF2L promoter was significantly increased by treatment of rat primary neurons with forskolin or dbcAMP, but not PC12, C6 and SH-SY5Y cells. Consistently, treatment with forskolin or dbcAMP could enhance endogenous SNF2L mRNA levels also only in rat primary neurons. CONCLUSION: These results suggest that the CRE consensus sequence in the SNF2L proximal promoter most likely confers constitutive activation and regulation by cAMP in neural cells.

Gene mapping of a nonsyndromic hearing impairmint family / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To map the gene responsible for nonsyndromic hearing impairment in a consanguineous family.</p><p><b>METHODS</b>Firstly, X chromosome scanning was used to exclude X chromosome. Secondly, candidate gene analyzing and genome scanning were performed by homozygosity mapping. Then, additional markers flanking the tightly linked marker were tested to confirm linkage and decide the candidate region.</p><p><b>RESULTS</b>The nonsyndromic hearing impairment of this family was autosomal recessive. Twenty-five known genes were excluded. Autosomal genome scanning indicated that D17S1293 was tightly linked with disease gene. And further study mapped the disease gene to a 5.07 cM interval bounded by D17S1850 and D17S1818.</p><p><b>CONCLUSION</b>The disease gene of the family is mapped to a 5.07 cM interval between D17S1850 and D17S1818, which is a new locus of autosomal recessive nonsyndromic hearing impairment.</p>

Genomic structure of low density lipoprotein receptor related protein 5 gene / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To determine the genomic structure of low density lipoprotein receptor related protein 5 (LRP5) gene.</p><p><b>METHODS</b>cDNA sequence encoding LRP5 was used to screen genomic clones containing LRP5 gene by computer hybridization approach. By comparing the cDNA sequence of LRP5 with the genomic sequences, the genomic structure of LRP5 was determined, and then it was conformed by amplifying and sequencing the sequences of exons and splicing junction.</p><p><b>RESULTS</b>The genomic sequence of LRP5 gene was 131.6 kb in length, containing 23 exons and 22 introns. Three single nucleotide polymorphisms were detected within the coding sequences of LRP5 gene, namely A459G in exon 2, C2220T in exon 10 and G4416C in exon 21. Four polymorphic markers, D11S1917, D11S4087, D11S1337 and D11S4178, located in the 5' flank sequence, introns 1, 4, and 13 of the LRP5 gene, respectively.</p><p><b>CONCLUSION</b>The characterization of genomic structure of LRP5 gene allows the investigators to detect disease-causing mutation within the gene and further study the function of LRP5 gene.</p>

Linkage analysis of X-linked nuclear protein gene in Smith-Fineman-Myers syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To determine the linkage between Smith-Fineman-Myers syndrome (SFMS) and X-linked nuclear protein(XNP) locus.</p><p><b>METHODS</b>Polymerase chain reaction and denaturing polyacrylamide gel electrophoresis were used to genotype two polymorphic short tandem repeats within XNP gene.</p><p><b>RESULTS</b>One of the two short tandem repeats was informative in SFMS family from Shandong, China. Recombination between SFMS locus and XNP gene was observed in the SFMS family.</p><p><b>CONCLUSION</b>XNP gene is not associated with the disease in the SFMS family from Shandong, China. SFMS exhibits locus heterogeneity at molecular level.</p>

The C677T mutation in the methylenetetrahydrofolate reductase gene and its association with deep vein thrombophilia in Shandong Hans / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To study the prevalence of methylenetetrahydrofolate reductase (MTHFR) C677T genotype and its association with deep vei n thrombophilia in Chinese.</p><p><b>METHODS</b>Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was conducted to examine mutation with 63 deep vein thrombophilic patients and 80 health controls in Shandong Hans. The genotype frequencies were calculated by gene counting in patients and controls, and an analysis was made on the association of MTHFR C677T mutation with deep venous thrombosis in Shandong Hans.</p><p><b>RESULTS</b>In case- controls, the frequencies of C/T heterozygote were 41.27% and 43.75%; whereas those of T/T homozygote were 52.38% and 36.25%. Significantly elevated mutation was observed in patients(Chi-square=6.372, P 0.01 OR(T/T)=4.552 95% confidence interval:1.440-14.390, Chi-square =6.742 P=0.009).</p><p><b>CONCLUSION</b>The C677T mutation of methylenetetrahydrofolate reductase gene is a risk factor associated with deep vein thrombophilia in Shandong Hans.</p>