Xp21/A translocation: a rarely considered genetic cause for manifesting carriers of duchenne muscular dystrophy.

Clinically manifesting carriers of Duchenne muscular dystrophy (DMD) are rare among the pediatric population. A standardized diagnostic procedure in supposed DMD carriers entails performing a Multiplex Ligation-dependent Probe Amplification analysis of the DMD gene first, then taking a muscle biopsy to confirm reduced dystrophin levels and/or finally a complete sequencing of the DMD gene. We describe a girl with high-elevated creatine kinase, myalgia, and cardiomyopathy. Muscle biopsy showed a dystrophic pattern and nearly absent expression of dystrophin. Diagnosis could not be confirmed by molecular genetic procedures. Because of a mild mental retardation, a chromosome analysis and molecular karyotyping were performed, revealing a balanced translocation t(X;4)(p21;q31).arr(1-22,X)x2 dn with breakpoint on the X-chromosome within an intron of the DMD gene. The inactivation of the nonderivative X-chromosome was found to be in a nonrandom pattern, resulting in a functionally balanced karyotype and thus leading to a manifesting DMD carrier in this case. Chromosome analysis should be recommended in cases of genetically unsolved DMD carriers as a part of the standard genetic procedures.

Association of serotonin-1A and -2A receptor promoter polymorphisms with depressive symptoms, functional recovery, and pain in patients 6 months after lumbar disc surgery.

Single nucleotide polymorphisms (SNPs) in the serotonergic (5HT) system seem to have modulatory effects on depression and physical function. Preliminary evidence suggests that gene×environment interactions play a role in the development of depression, with somatic complaints serving as environmental stressors. We hypothesized that pain intensity may serve as a stress factor that modulates the association between SNPs in the 5HT system and depression. We investigated symptoms of pain, depression, physical functioning, and disability in 224 patients 6months after lumbar disc surgery. Associations between these variables and functional promoter SNPs in the serotonin receptor genes 5HTR1A (rs6295) and 5HTR2A (rs6311) were analyzed. For 5HTR2A, we found a significant gene×environment×sex interaction, as female patients carrying at least one A allele of the -1438A/G promoter SNP had significantly higher depression scores when confronted with severe pain compared to women harboring the GG genotype (P=.005). For 5HTR1A, patients homozygous for the -1019 G allele presented higher Beck Depression Inventory scores relative to the CG/CC group, indicating a major effect of this SNP on depression. Furthermore, women homozygous for either the 5HTR1A G allele or the 5HTR2A A allele had lower levels of physical functioning than patients with the other genotypes. These results suggest that 5HTR1A and 5HTR2A promoter variations have gender-dependent modulatory effects on depression and physical function in patients with pain. Furthermore, this study demonstrates that pain after lumbar surgery modulates the association between 5HT gene polymorphisms and depression.

High-density oligonucleotide-based resequencing assay for mutations causing syndromic and non-syndromic forms of thoracic aortic aneurysms and dissections.

Thoracic aortic aneurysm and dissection is associated with increasing mortality rate that may occur as part of a syndrome or as an isolated familial condition. Several genes have been implicated in causing TAAD, though an appropriate genetic test for their parallel testing is not yet available. Herein, we describe the novel 117-kb "MFSTAAD chip" that may help to understand the genetic basis of TAAD. A custom duplicate resequencing assay was developed to cover eight genes previously described in TAAD; FBN1, TGFBR1&2, COL3A1, MYH11, ACTA2, SLC2A10 and NOTCH1. GSEQ and SeqC software were used for data analysis. The analytical sensitivity of the assay was validated by the recognition of 182 known mutations (153 point mutations, 21 deletions, 7 insertions and 1 duplication) and a cohort of 28 patients were selected to determine the mutation yield, whereby 18 of them were previously negative for mutations in the genes FBN1 and TGFBR2. The assay had significantly higher sensitivity for point mutations (100%) and the largest deletion of 16 bp was detectable through a decline in the hybridization strength. The overall analytical sensitivity was 85%. Mutation testing of 28 unrelated TAAD patients revealed 4 known and 6 possibly pathogenic mutations with a mutation yield of 32%. The MFSTAAD chip is an alternative tool to next-generation sequencing that allows parallel analysis of several genes on a single platform. Refinements in the probe design and data analysis software will increase the analytical sensitivity of insertions and deletions making this assay even more applicable for clinical testing.

Three novel mutations in the ACTA2 gene in German patients with thoracic aortic aneurysms and dissections.

Mutations in the gene encoding smooth muscle cell alpha actin (ACTA2) have recently been shown to cause familial thoracic aortic aneurysms leading to type A dissections (TAAD) and predispose to premature stroke and coronary artery disease. In order to further explore the role of ACTA2 variations in the pathogenesis of TAAD, we sequenced the coding regions of this gene in 40 unrelated German patients with TAAD (with (n=21) or without (n=19) clinical features suggestive of Marfan syndrome). All patients had previously tested negative for mutations in the FBN1 and TGFBR2 genes. We identified three novel ACTA2 mutations and mapped them on a three-dimensional model of actin. Two mutations affect residues within (M49V) or adjacent to (R39C), the DNAse-I-binding loop within subdomain 2 of alpha actin. They were observed in families with recurrent aortic aneurysm (R39C) or aortic dissection (M49V). The third mutation causes an exchange in the vicinity of the ATP-binding site (G304R) in a patient thought to have isolated TAAD. None of the affected individuals had clinical features typical for Marfan syndrome, and no case of premature stroke or coronary artery disease was reported from the affected families. In conclusion, we underscore the role of ACTA2 mutations in nonsyndromic TAAD and suggest that ACTA2 should be included in the genes routinely investigated for syndromic and nonsyndromic TAAD. Detailed clinical investigations of additional families are warranted to further explore the full range of phenotypic signs associated with the three novel mutations described here.

Polymorphisms of genes coding for ghrelin and its receptor in relation to colorectal cancer risk: a two-step gene-wide case-control study.

BACKGROUND: Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor (GHSR), has two major functions: the stimulation of the growth hormone production and the stimulation of food intake. Accumulating evidence also indicates a role of ghrelin in cancer development. METHODS: We conducted a case-control study to examine the association of common genetic variants in the genes coding for ghrelin (GHRL) and its receptor (GHSR) with colorectal cancer risk. Pairwise tagging was used to select the 11 polymorphisms included in the study. The selected polymorphisms were genotyped in 680 cases and 593 controls from the Czech Republic. RESULTS: We found two SNPs associated with lower risk of colorectal cancer, namely SNPs rs27647 and rs35683. We replicated the two hits, in additional 569 cases and 726 controls from Germany. CONCLUSION: A joint analysis of the two populations indicated that the T allele of rs27647 SNP exerted a protective borderline effect (Ptrend = 0.004).

Unusual Charcot-Marie-Tooth phenotype due to a mutation within the intracellular domain of myelin protein zero.

Myelin protein zero (MPZ/P0) constitutes a major component of compact peripheral myelin. We report a family with a missense mutation, c.700G>T p.Asp234Tyr (deviant nomenclature: c.670G>T, p.Asp224Tyr), within the intracellular domain of myelin protein zero, who has distal sensorimotor symptoms, cramps, restless legs syndrome, neuropathic pain, and carpal tunnel syndrome. The index patient responded to intravenous immunoglobulin and immunosuppression, so there may be a possible secondary autoimmune process, probably triggered by altered antigen presentation due to mutated MPZ protein.

Severe demyelinating hypertrophic polyneuropathy caused by a de novo frameshift mutation within the intracellular domain of myelin protein zero (MPZ/P0).

Hereditary motor and sensory neuropathy (HMSN), also known as Charcot-Marie-Tooth disease (CMT) is a group of clinically and genetically heterogeneous neuropathies classically divided into demyelinating (CMT1) and axonal forms (CMT2). The most common demyelinating form is CMT1A with an underlying duplication in the gene coding for the peripheral myelin protein 22 (PMP22). Less frequently, mutations in the myelin protein zero gene (MPZ/P(0)) account for demyelinating CMT1B, Dejerine-Sottas syndrome (DSS), or congenital hypomyelinating neuropathy (CHN). Here, we report a patient with a severe, early-onset hypertrophic and dysmyelinating neuropathy. The patient exhibits a novel frameshift mutation with an insertion of a single T-nucleotide on position c.618_619 of the MPZ gene resulting in a premature stop M207fsX38.

Analysis of rare APC variants at the mRNA level: six pathogenic mutations and literature review.

In monogenic disorders, the functional evaluation of rare, unclassified variants helps to assess their pathogenic relevance and can improve differential diagnosis and predictive testing. We characterized six rare APC variants in patients with familial adenomatous polyposis at the mRNA level. APC variants c.531 + 5G>C and c.532-8G>A in intron 4, c.1409-2_1409delAGG in intron 10, c.1548G>A in exon 11, and a large duplication of exons 10 and 11 result in a premature stop codon attributable to aberrant transcripts whereas the variant c.1742A>G leads to the in-frame deletion of exon 13 and results in the removal of a functional motif. Mutation c.1548G>A was detected in the index patient but not in his affected father, suggesting mutational mosaicism. A literature review shows that most of the rare APC variants detected by routine diagnostics and further analyzed at the transcript level were evaluated as pathogenic. The majority of rare APC variants, particularly those located close to exon-intron boundaries, could be classified as pathogenic because of aberrant splicing. Our study shows that the characterization of rare variants at the mRNA level is crucial for the evaluation of pathogenicity and underlying mutational mechanisms, and could lead to better treatment modalities.

Expanded HSAN4 phenotype associated with two novel mutations in NTRK1.

Hereditary sensory and autonomic neuropathy type IV (HSAN4) is a severe autosomal recessive disorder characterized by childhood onset of sensory and autonomic dysfunction leading to hyperthermia, recurrent infections and physical impairment due to complications of osteoarthritis. Cognitive impairment and aggressive behaviour is common. HSAN4 is caused by mutations in the NTRK1 gene coding for the tyrosine kinase receptor A. We present detailed description of a rare, mild HSAN4 phenotype associated with two novel NTRK1 mutations. This Swedish patient presents with an adult onset of painful Charcot arthropathy, prolonged wound healing, discrete polyneuropathy, hypohidrosis without further autonomic dysfunction and no cognitive affection.