MLPA-based evidence for sequence gain: pitfalls in confirmation and necessity for exclusion of false positives.

Multiplex ligation-dependent probe amplification (MLPA) has become a standard method for identifying copy number mutations in diagnostic and research settings. The occurrence of false-positive deletion findings and the underlying causes are well recognized, whereas false-positive duplication/amplification findings have not been appreciated so far. We here present three pertinent cases which were only identified on extended, nonstandard secondary analyses.

Mitochondrial DNA polymorphisms/haplogroups in hereditary spastic paraplegia.

Mitochondrial dysfunction could contribute to the development of spastic paraplegia. Among others, two of the genes implicated in hereditary spastic paraplegia encoded mitochondrial proteins and some of the clinical features frequently found in these patients resemble those observed in patients with mitochondrial DNA (mtDNA) mutations. We investigated the association between common mtDNA polymorphisms and spastic paraplegia.

Spinocerebellar ataxia type 15: diagnostic assessment, frequency, and phenotypic features.

Background: To guide time- and cost-efficient analyses of the increasing number of autosomal-dominant spinocerebellar ataxia genes (SCAs), more information about frequency distributions, phenotypic characteristics and optimal diagnostic strategies is warranted.

Objective: To assess the prevalence and phenotypic spectrum of SCA15 and to confirm multiplex ligation-dependent probe amplification (MLPA) as a robust and efficient strategy for routine molecular diagnosis.

Methods: Fifty-six German SCA families negative for common repeat expansions were screened for ITPR1 deletions by MLPA.

Mutational spectrum of the SPG4 (SPAST) and SPG3A (ATL1) genes in Spanish patients with hereditary spastic paraplegia.

Background: Hereditary Spastic Paraplegias (HSP) are characterized by progressive spasticity and weakness of the lower limbs. At least 45 loci have been identified in families with autosomal dominant (AD), autosomal recessive (AR), or X-linked hereditary patterns. Mutations in the SPAST (SPG4) and ATL1 (SPG3A) genes would account for about 50% of the ADHSP cases.

Mutational screening of the mortalin gene (HSPA9) in Parkinson's disease.

Mortalin is a mitochondrial chaperone of the heat shock protein 70 family. Mortalin plays a central role in mitochondrial biogenesis through its capacity to direct the import of nuclear-encoded proteins into the mitochondria. As mitochondrial dysfunction has been involved in Parkinson's disease (PD), changes in mortalin function and expression could manifest as a higher risk of developing PD.

Mutational screening of the mitochondrial transcription factors B1 and B2 (TFB1M and TFB2M) in Parkinson's disease.

Mitochondrial dysfunction has been implicated in Parkinson's disease (PD). The nuclear encoded transcription factors A, B1 and B2 are essential for mitochondrial DNA replication. Sequence variants at the genes encoding TFAM, TFB1M and TFB2M could contribute to the risk of developing PD.

Mitochondrial transcription factor A (TFAM) gene variation and risk of late-onset Alzheimer's disease.

Impaired mitochondrial function and an increased number of mutations in mitochondrial DNA (mtDNA) has been found in brains of patients with late-onset Alzheimer's disease (LOAD). The TFAM-gene encodes the mitochondrial transcription factor A, a protein that controls the transcription, replication, damage sensing, and repair of mtDNA. TFAM is on human chromosome region 10q21.

Mitochondrial transcription factor A (TFAM) gene variation in Parkinson's disease.

Mitochondrial function is necessary to supply the energy required for cell metabolism. Mutations/polymorphisms in mitochondrial DNA (mtDNA) have been implicated in Parkinson's disease (PD). The mitochondrial transcription factor A (TFAM) controls the transcription of mtDNA and regulates the mtDNA-copy number, thus being important for maintaining ATP production.

No association between Parkinson's disease and three polymorphisms in the eNOS, nNOS, and iNOS genes.

Nitric oxide synthases (NOS) and mitochondrial DNA-polymorphisms have been associated with the risk of developing Parkinson's disease (PD). In this report, we genotyped 450 PD-patients and 200 controls for three polymorphisms in the endothelial, inducible and neuronal NOS-genes, and for the T4336C and A10398G mitochondrial DNA-polymorphisms. None of the eNOS (intron 4 VNTR), iNOS (exon 22 A/G), or nNOS (exon 29T/C) were significantly associated with PD.