Exome sequencing reveals three homozygous missense variants in SNRPA in two sisters with syndromic intellectual disability.

Splicing-related gene mutations might affect the expression of a single gene or multiple genes and cause clinically heterogeneous diseases. With the advent of next-generation sequencing, several splicing gene mutations have been exposed, yet most major spliceosome genes have no reports of germline mutations and therefore, their effects are largely unknown. We describe the previously unreported concurrence of intellectual disability, short stature, poor speech, and minor craniofacial and hand anomalies in 2 female siblings with 3 homozygous missense variants in SNRPA (a component of the U1 small nuclear ribonucleoprotein complex) characterized by homozygosity mapping and whole exome sequencing. Combined, c.97A>G, c.98T>C, and c.100T>A, in exon 2 of SNRPA lead to p.Ile33Ala and p.Phe34Ile exchanges, which were predicted in silico to be deleterious. Although both patients exhibited some clinical features seen in other spliceosomal disorders, their complete clinical phenotype appears to be rather uncommon, a finding that may further support the notion that mutations in components of the major spliceosome do not strictly lead to the same syndromes/phenotypes.

Evidence for a recessive PMP22 point mutation in Charcot-Marie-Tooth disease type 1A.

Charcot-Marie-Tooth disease type 1A (CMT1A) is an autosomal dominant neuropathy that can be caused by dominant point mutations in PMP22 which encodes a peripheral nerve myelin protein. Usually, CMT1A is caused by the duplication of a 1.5-megabase (Mb) region on chromosome 17p11.2-p12 containing PMP22. Deletion of a similar 1.5-Mb region is associated with hereditary neuropathy with liability to pressure palsies (HNPP), a clinically distinct neuropathy. We have identified a severely affected CMT1 patient who is a compound heterozygote for a recessive PMP22 point mutation, and a 1.5 Mb deletion in 17p11.2-p12. A son heterozygous for the PMP22 point mutation had no signs of neuropathy, while two others heterozygous for the deletion had HNPP, suggesting that point mutations in PMP22 can result in dominant and recessive alleles contributing to CMT1A.

Association between septic patient mortality and blood survivin concentrations.

OBJECTIVE: Survivin is a member of inhibitors of apoptosis proteins family. There are not data about the association between mortality of septic patients and blood survivin concentrations. Therefore, the objective of this study was to determine whether exist that association. DESIGN: Observational and prospective study. SETTING: Three Spanish Intensive Care Units. PATIENTS: Patients with sepsis or septic shock according to Sepsis-3 Consensus criteria. INTERVENTIONS: Serum survivin concentrations were determined at moment of sepsis diagnosis. MAIN VARIABLE OF INTEREST: Mortality at 30 days. RESULTS: A total of 204 patients were included in the study, of which 75 (36.8%) died in the first 30 days. Lower age (p<0.001), serum lactic acid levels (p=0.001), rate of septic shock (p=0.001) and SOFA (p<0.001), and higher serum survivin levels (p=0.001) exhibited surviving (n=129) than non-surviving patients (n=75). We found in multiple logistic regression analysis an association between serum survivin concentrations and mortality independently of SOFA, lactic acid, age, INR, activated partial thromboplastin time (aPTT) and empiric antimicrobial treatment adequate (OR=0.968; 95% CI=0.946-0.990; p=0.005), and also independently of APACHE-II, lactic acid, platelet, INR, aPTT and empiric antimicrobial treatment adequate (OR=0.966; 95% CI=0.943-0.989; p=0.004). CONCLUSIONS: There is an association between septic patient mortality and low blood survivin concentrations.

Blood caspase-8 concentrations and mortality among septic patients.

OBJECTIVE: No data are available on blood caspase-8 concentrations (the initiator caspase in the extrinsic apoptosis pathway) in septic patients. The present study thus describes the blood caspase-8 concentrations in survivors and non-survivors, and examines the possible association between blood caspase-8 concentrations and mortality in septic patients. DESIGN: A prospective observational study was carried out. SETTING: Three Spanish Intensive Care Units. PATIENTS: Septic patients. INTERVENTIONS: Serum caspase-8 concentrations were determined at the diagnosis of sepsis. MAIN VARIABLE OF INTEREST: Mortality after 30 days. RESULTS: Patients not surviving at day 30 (n=81) compared to surviving patients (n=140) showed higher serum caspase-8 levels (p<0.001). Multiple logistic regression analysis found an association between serum caspase-8 levels>43.5ng/ml and mortality (OR=3.306; 95%CI=1.619-6.753; p=0.001). The area under the curve (AUC) for mortality predicted by serum caspase-8 levels was 67% (95% CI=60-73%; p<0.001). CONCLUSIONS: The novel findings of our study were that blood caspase-8 concentrations are higher in non-survivors than in survivors, and that there is an association between blood caspase-8 concentrations and mortality in septic patients.

Blood caspase-8 concentrations and mortality among septic patients.

OBJECTIVE: No data are available on blood caspase-8 concentrations (the initiator caspase in the extrinsic apoptosis pathway) in septic patients. The present study thus describes the blood caspase-8 concentrations in survivors and non-survivors, and examines the possible association between blood caspase-8 concentrations and mortality in septic patients. DESIGN: A prospective observational study was carried out. SETTING: Three Spanish Intensive Care Units. PATIENTS: Septic patients. INTERVENTIONS: Serum caspase-8 concentrations were determined at the diagnosis of sepsis. MAIN VARIABLE OF INTEREST: Mortality after 30 days. RESULTS: Patients not surviving at day 30 (n=81) compared to surviving patients (n=140) showed higher serum caspase-8 levels (p<0.001). Multiple logistic regression analysis found an association between serum caspase-8 levels>43.5ng/ml and mortality (OR=3.306; 95%CI=1.619-6.753; p=0.001). The area under the curve (AUC) for mortality predicted by serum caspase-8 levels was 67% (95% CI=60-73%; p<0.001). CONCLUSIONS: The novel findings of our study were that blood caspase-8 concentrations are higher in non-survivors than in survivors, and that there is an association between blood caspase-8 concentrations and mortality in septic patients.

Anti-obesity effects of kaempferol by inhibiting adipogenesis and increasing lipolysis in 3T3-L1 cells.

Kaempferol is a natural flavonoid widely found in fruits, vegetables, and tea. Kaempferol possesses beneficial biological properties such as anti-inflammatory and antioxidant activities. Positive energy balance during obesity correlates with a pro-inflammatory chronic state. In this context, we hypothesized that kaempferol might promote anti-obesity effects by modulating adipogenesis and lipolytic pathways. Adipocyte viability at 24, 48, and 72 h was measured by an ATP-based assay. Pre-adipocytes (day 0) or mature adipocytes (day 12) were treated with 60 µM kaempferol until day 21 to evaluate its potential anti-adipogenic and lipolytic effect, respectively. Total lipid accumulation was assessed using Oil Red O staining assay. Gene expression was measured by RT-qPCR to evaluate the effect of kaempferol on adipogenesis and lipolysis gene expression. Our results showed a dose-dependent effect of kaempferol treatment on cell viability promoting cell death at higher than 60 µM concentration. Pre-adipocytes stimulation by 60 µM kaempferol resulted in 62% adipogenesis inhibition whereas in mature adipocytes, it reduced 39% intracellular lipid accumulation. Also, 60 µM kaempferol treatment decreased Cebpa mRNA expression when compared to control cells. In contrast, Pnpla2 and Lipe gene expression were upregulated in 3T3-L1 cells incubated with 60 µM kaempferol. In summary, our results showed that kaempferol modulates adipogenic differentiation in 3T3-L1 cells by promoting downregulation of Cebpa gene expression and decreasing lipid accumulation in mature adipocytes by its positive effects on Pnpla2 and Lipe mRNA levels. Kaempferol might display an anti-obesity effect.

[Levofloxacin in the treatment of nosocomial infection in critically ill patients]. / Levofloxacino en el tratamiento de infecciones nosocomiales en pacientes críticos.

INTRODUCTION: Levofloxacin (LVX) is one of the most frequently used antibiotics in critical patients admitted to Spanish Intensive Care Units (ICU). Their use in community-acquired infections has been widely documented, while it is less frequent and known in nosocomial infections (NI). OBJECTIVE: To describe the indications and utilization patterns of LVX in the treatment of NI in patients admitted to Spanish ICU. MATERIAL AND METHODS: Open-label, retrospective, observational and multicenter study. All patients admitted to ICU and who were being treated for NI with LVX in the years 2004-2005 were included. A case report form (CRF) was drawn up and included demographic, infection, treatment, infectious process and patient development variables. NI-dependent LVX usage was described. A logistical regression analysis was carried out in order to identify the variables associated with a satisfactory response. Results are expressed by means of the odds ratio and a 95% confidence interval. RESULTS: A total of 949 patients who were given LVX for the treatment of 1,103 NI were recruited in 87 ICU: 460 (41.7%) with non-mechanical ventilation associated pneumonia, 256 (23.2 %) mechanical-ventilation associated pneumonia, 107 (9.7 %) with primary or vascular catheter-related bacteremia, 47 (4.3 %) with urethral catheter-related urinary infections, 42 (3.8%) with organspace or deep surgical infections and 191 (17.3%) who had other types of infection. An APACHE II upon admission of 19.6 (SD: 8) and severe sepsis or septic shock systemic response in 50.4% of all cases. On 776 (82.7%) occasions treatment was initiated on an empirical basis and in 589 (62.1%) cases the dose of choice was of 0.5 g/ 12 h, with a mean duration of 9 days. In 738 (77.8 %) patients, LVX was used in association with other antibiotics. The clinical response by treatment end was rated as satisfactory in 67.4 % of all NI. Factors related to a non-satisfactory response were as follows: APACHE II (OR: 1.05; 95% CI: 1.028-1.078); septic shock (OR: 2.62; 95 % CI: 1.623-4.219); the requirement for changes in treatment due to poor clinical progress (OR: 66.67; 95% CI: 15.384-250), the presence of non-covered microorganisms (OR: 6.58; 95% CI: 3.663-11.765), the appearance of new resistant pathogens (OR: 6.94; 95 % CI: 2.445- 19.608) or the diagnosis of a new infection (OR: 3.68; 95% CI: 1.504-8.929); solid neoplasm (OR: 1.98; 95% CI: 1.156-3.899); chronic liver disease (OR: 3.11; 95 % CI: 1.429-8.475) and the absence of etiology confirmation (OR: 2.39; 95 % CI: 1.624-3.510). One or more adverse events which were possibly or probably related to the use of LVX were detected in 104 (11.0%) patients. Total intra-ICU mortality amounted to 26.1%, while the accumulated in-hospital mortality was 33.8%. CONCLUSIONS: LVX is a common therapeutic option in the treatment of nosocomial infections in critical patients. It is predominantly used in an empirical manner, at a dose of 0.5 g every 12 hours and in combination with other antibiotics.

HGH isoforms: cDNA expression, adipogenic activity and production in cell culture.

We have isolated, cloned and achieved functional expression of the cDNAs for both 22 kDa and 20 kDa human growth hormone (hGH) isoforms. A selective cDNA cloning strategy was used to preferentially and simultaneously obtain both hGH 22 kDa and hGH 20 kDa cDNAs. These were used to construct minigenes which were subcloned into two eukaryotic expression vectors and then introduced transiently in COS-7 cells and stably into CHO cells in culture. Transfection assays in COS-7 cells of both minigenes allowed the detection of the secreted hGH 22 kDa and hGH 20 kDa. These hGHs isoforms secreted into COS-7 medium were able to specifically promote differentiation of 3T3-F442A preadipocytes to adipose cells. Adipocyte differentiation was quantitated by Oil Red O triacylglycerol staining or glycerophosphate dehydrogenase activity. Furthermore, stable CHO cell lines have been derived that produce these hGH isoforms.

Increased detection of human immunodeficiency virus antigen carriers by simultaneous assay of plasma and extracts from resting and phytohaemagglutinin-stimulated peripheral blood mononuclear cells.

Antigenaemia due to human immunodeficiency virus (HIV) is thought to be significant either before the appearance of a specific antibody response, or after its decline during terminal stages. In order to increase the rate of detection of HIV antigen carriers, regardless of the stage or despite the presence of specific serum antibodies, we assayed, simultaneously, plasma samples and extracts from resting and phytohaemagglutinin-stimulated mononuclear cells from 25 infected, anti-body-positive individuals and 10 healthy, antibody-negative female volunteer blood donors. We detected the presence of HIV antigen in at least one of the three types of specimens obtained from all the 25 infected subjects but in none of the 10 healthy blood donors. This approach might prove most useful for the study of patients with controversial or equivocal antibody test results.

Folate levels and N(5),N(10)-methylenetetrahydrofolate reductase genotype (MTHFR) in mothers of offspring with neural tube defects: a case-control study.

BACKGROUND: Neural tube defects (NTDs) have been associated with biochemical factors involved in the conversion of homocysteine to methionine as folate deficiency and the mutation 677T in the N(5),N(10)-methylenetetrahydrofolate reductase gene (MTHFR). METHODS: A case-control study was performed to detect this mutation in 38 unrelated women with NTD deceased products and 31 mothers without antecedents of NTD offspring. All products were born in Nuevo León (northeastern Mexico) during 1997. Erythrocyte and plasmatic folate levels and the genotype of the 677 polymorphism at the MTHFR locus were analyzed in both groups. RESULTS: Although no significant differences were found in mean blood folate levels, the percentage of women in the case group with erythrocyte folate levels <160 ng/mL was significantly higher than in the control group (75 vs. 51.2%, p <0.05). The proportion of women with plasma folate levels <3.5 ng/mL was higher in the case group (16.2 vs. 0%, p <0.01). Genotype analysis demonstrated a significantly higher proportion of 677T homozygous mothers with NTD products (39.6 vs. 9.1%, p <0.05). Allele frequencies for the 677T mutation were 0.55 and 0.36 for cases and controls, respectively. The odds ratio (OR) for having a NTD product was 6.1 (95%, CI 1.56-23.6) for homozygous 677T mothers vs. homozygous 677C and heterozygous mothers. Significantly low levels of erythrocyte folate were found in the 677C homozygous case group and in plasma folate in the 677C/677T heterozygous case mothers. CONCLUSIONS: Our study suggests that folate deficiency and MTHFR unfavorable genotype in mothers are important risk factors for severe NTD phenotype in our population.

[677T mutation of the MTHFR gene in adenomas and colorectal cancer in a population sample from the Northeastern Mexico. Preliminary results]. / Mutación 677T del gen MTHFR en adenomas y cáncer colorrectal en una muestra de la población del noreste de México. Resultados preliminares.

INTRODUCTION: Adequate intake of folates has been associated to low prevalence of colon cancer. Methylenetetrahydrofolate reductase enzyme (MTHFR) plays an important role in folate metabolism. The role of the 677 mutation at the MTHFR gene in the risk for colorectal cancer remains controversial. A recent report established that this mutation has a high prevalence in the healthy Mexican population. AIMS: To analyze the prevalence of 677T MTHFR mutation in patients with colorectal cancer and controls without chronic gastrointestinal disorders. METHODS: Seventy-four colorectal cancer, 32 adenomas and 110 normal samples were analyzed. Patients and controls were matched for sex and age. For each sample, DNA isolation, PCR, and mutation detection by restriction enzyme digestion were performed to determine the allele at the 677 position in the MTHFR gene. RESULTS: Genotype 677C/677C was found in 18.7, 20.3, and 30.9% in adenomas, cancer lesions and controls, respectively. Frequencies of the 677C/677T genotype were 59.4, 56.7, and 47.3%, in adenomas, cancer lesions, and controls, respectively. Genotype 677T/677T was found in 21.9, 23.0, and 21.8% in adenomas, cancer lesions, and controls, respectively. The odds ratio between genotypes carrying the mutation (T/T and C/T) and normal genotype (CC) was 1.81 (IC 95% 0.97-3.3), chi 2 = 3.5, p = 0.06. CONCLUSION: Our results showed that persons who carry the 677T mutation at MTHFR locus have a tendency for an increased risk for colorectal cancer. This study supports the basic concept that low levels of folic acid contribute with the colorectal cancer pathogenesis. Our lack of statistic significance may be due to reduced sample size.

[Synchronized independent pulmonary ventilation in the treatment of adult respiratory distress syndrome]. / Ventilación pulmonar independiente sincronizada en el tratamiento del síndrome de distrés respiratorio del adulto.

INTRODUCTION: Synchronized independent lung ventilation (SILV) is an effective mode of mechanical ventilation for treating both unilateral and bilateral pulmonary lesions. Oxygenation improves with an increase in the ventilation/perfusion ratio and also diminishes the risk of barotrauma. We describe our broad experience with this technique. Our main objective was to confirm whether SILV is able to improve the alveolar-arterial oxygen difference [P(A-a)O2] of patients with severe adult respiratory distress syndrome (ARDS) in whom conventional mechanical ventilation has not brought about improvement after being used for over 48 hours. PATIENTS AND METHODS: We carried out a descriptive, open, controlled prospective study of 45 patients with severe ARDS, enrolled from among 68 who underwent treatment with SILV. The most frequent cause of ARDS in our study was multiple trauma. The patients diagnosed of ARDS who did not improve with conventional mechanical ventilation were treated with SILV. Clinical characteristics and mortality are described. APACHE II scores, PAOA-aO2, dynamic distensibility were analyzed before and after SILV. The results of SILV were considered good if PA-aO2 improved at least 30% within 48 hours, with no increase in distensibility. RESULTS: No complications due to the technique were observed. Twenty-two patients (48.8%) died, 18 as a result of multiple organ failure and only one (4.5%) because of hypoxia. The improvements in APACHE II and (PA-aO2 were statistically significant, while distensibility did not change. The result was defined as good in most cases (n = 34, 83.8%). CONCLUSIONS: SILV is useful for providing ventilatory support when ARDS fails to improve with conventional mechanical ventilation. Clear improvement in respiratory function was observed, with significant decrease in PA-aO2 and no change in distensibility. SILV is a safe technique with few complications and can be managed by the intensive care unit nursing staff.

Strong association of variants around FOXE1 and orofacial clefting.

Nonsyndromic orofacial clefting (nsOFC) is a common, complex congenital disorder. The most frequent forms are nonsyndromic cleft lip with or without cleft palate (nsCL/P) and nonsyndromic cleft palate only (nsCPO). Although they are generally considered distinct entities, a recent study has implicated a region around the FOXE1 gene in both nsCL/P and nsCPO. To investigate this hypothesis, we analyzed the 2 most strongly associated markers (rs3758249 and rs4460498) in 2 independent samples of differing ethnicities: Central European (949 nsCL/P cases, 155 nsCPO cases, 1163 controls) and Mayan Mesoamerican (156 nsCL/P cases, 10 nsCPO cases, 338 controls). While highly significant associations for both single-nucleotide polymorphisms were obtained in nsCL/P (rs4460498: p Europe = 6.50 × 10(-06), p Mayan = .0151; rs3758249: p Europe = 2.41 × 10(-05), p Mayan = .0299), no association was found in nsCPO (p > .05). Genotyping of rs4460498 in 472 independent European trios revealed significant associations for nsCL/P (p = .016) and nsCPO (p = .043). A meta-analysis of all data revealed a genomewide significant result for nsCL/P (p = 1.31 × 10(-08)), which became more significant when nsCPO cases were added (p nsOFC = 1.56 × 10(-09)). These results strongly support the FOXE1 locus as a risk factor for nsOFC. With the data of the initial study, there is now considerable evidence that this locus is the first conclusive risk factor shared between nsCL/P and nsCPO.

Delineation of a de novo 7q21.3q31.1 Deletion by CGH-SNP Arrays in a Girl with Multiple Congenital Anomalies Including Severe Glaucoma.

In this study, we present a female patient with a constitutional de novo deletion in 7q21.3q31.1 as determined by G-banding and CGH-SNP arrays. She exhibited, among other features, psychomotor retardation, congenital severe bilateral glaucoma, a cleft palate, and heart defect. Microarray assay disclosed a deleted 12.5-Mb region roughly 88 kb downstream the ectrodactyly critical region; thus, the patient's final karyotype was 46,XX.arr 7q21.3q31.1(96,742,140-109,246,085)×1 dn. This girl represents the fourth patient described so far with congenital glaucoma and a deletion encompassing or overlapping the 7q21.3q31.1 region, and confirms the presence of a locus or loci related to such a clinical feature. According to our results, the proneness to ocular defects secondary to 7q intermediate deletions could be caused by co-deletion of TAC1, HBP1, and a small cluster of cytochrome P450 genes (subfamily 3A). This conclusion is supported by their functional roles and expression locations as well as because TAC1 is related to the functional pathway of the MYOC gene whose mutations are linked to glaucoma. Moreover, given that this girl is clinically reminiscent of several phenotypes related to diverse deletions within 7q21q32, our results and observations offer a general overview of the gene content of deletions/phenotypes overlapping 7q21.3q31.1 and confirm that loci distal to DLX genes including the CUX1 gene and potential regulatory elements downstream from DLX5 are unrelated to ectrodactyly.

Positive association between vascular endothelial growth factor (VEGF) -2578 C/A variant and prostate cancer.

BACKGROUND: Vascular endothelial growth factor (VEGF) gene is an important angiogenesis regulator related to cancer development and progression. We evaluated the association between -2578 C/A (rs699947) VEGF polymorphism and PCa in Mexican subjects, to contribute to knowledge of VEGF role in genetic epidemiology of prostate cancer (PCa). OBJECTIVE: The aim of this study was to evaluate the association between -2578 C/A VEGF variant and PCa in Mexican population. METHODS: A total of 249 men (77 PCa cases and 172 controls) from the Northwestern region of Mexico were screened for the -2578 C/A VEGF variant. The polymorphism was determined by polymerase chain reaction-based restriction analysis. RESULTS: Genotype frequencies for C/C, C/A, and A/A, were 0.48, 0.49, 0.03 for cases and 0.41, 0.45, 0.14 for controls respectively. Genotype A/A of -2578 VEGF variant reduces the risk of PCa in an 84% among studied population (Odds Ratio 0.16; 95% CI: 0.04-0.71, P=0.007). C/C carriers showed an increased PCa risk of 6.1 times among the study population. CONCLUSIONS: Inheritance of -2578 A/A genotype of VEGF gene may modify PCa susceptibility risk in Mexican population.

Intraprostatic distribution and long-term follow-up after AdV-tk immunotherapy as neoadjuvant to surgery in patients with prostate cancer.

A phase I-II study to evaluate gene-mediated cytotoxic immunotherapy in newly diagnosed prostate cancer before radical prostatectomy was conducted in Monterrey, Mexico. First, to investigate delivery of adenovirus to the prostate, fluorescently labeled vector was injected into fresh prostatectomy specimens and distribution was visually analyzed. The optimal volume and site instillation was then used for transrectal ultrasound guided intraprostatic injection in 10 patients with adenocarcinoma scheduled for radical prostatectomy. Each received two apical and two basal 0.5 ml injections of AdV-tk for a total of 1 × 10(11) vp followed by 14 days of prodrug. Nine patients continued to tumor resection: six high risk, one intermediate and two low risk. In vivo vector distribution was analyzed from the resected tissue of four patients. Patients were monitored for tumor progression and acute and long-term safety. For vector delivery, two apical and two basal injections of 0.5 ml led to optimal organ-wide distribution ex vivo and in vivo. Cytotoxicity was evidenced by transient rise in PSA and tumor histology. There were no significant adverse events deemed related to the treatment and no late toxicities after median follow-up of 11.3 years. All six high-risk patients had positive surgical margins and one had seminal vesicle involvement. Despite slow PSA rise post surgery in three of these patients, none developed metastases. The intermediate- and low-risk patients had complete resections and none have progressed. In conclusion, in vivo transrectal ultrasound guided instillation of an adenoviral vector into four sites in the prostate was practical as an outpatient procedure, well tolerated and led to distribution throughout the intraprostatic tumor mass. AdV-tk demonstrated no significant acute or late toxicities. Trends in PSA and disease progression conveyed the possibility of a sustained immune response against residual disease.

A de novo sSMC(22) Characterized by High-Resolution Arrays in a Girl with Cat-Eye Syndrome without Coloboma.

Cat-eye syndrome (CES) results from trisomy or tetrasomy of proximal 22q originated by a small supernumerary marker chromosome (sSMC). Two critical regions for the major clinical features of CES (CESCRs) have been suggested; however, CES clinical presentation often does not correlate with the sSMC genetic content. We report here a CES girl without coloboma and carrier of a de novo type I sSMC(22) as determined by G- and C-banding, NOR staining and microarrays. This sSMC included 6 distal genes outside the original CESCR and led to a tetrasomy for 22q11.1-22q11.21. The patient's final karyotype was 47,XX,+psu dic(22)(q11.21).arr 22q11.1q11.21(15,250,000-17,035,860)×4 dn. The amplified region outside of CESCR included some genes that may be related to neurologic, heart and renal abnormalities. Conversely, even though the amplification included the CECR2 gene, a major candidate for eye features, there was no coloboma in the patient. The genetic delineation of the present sSMC further strengthens that the CES clinical presentation does not fit completely with the duplicated genetic content and that CES is actually a genomic disorder. Furthermore, since we observed no mosaicism, we believe that other mechanisms might be behind the variability of CES phenotypes as well, mainly those related with functional interactions among amplified genes.

Evidence for a dystrophin missense mutation as a cause of X-linked dilated cardiomyopathy.

BACKGROUND: X-linked dilated cardiomyopathy (XLCM) has previously been shown to be due to mutations in the dystrophin gene, which is located at Xp21. Mutations in the 5' portion of the gene, including the muscle promoter, exon 1, and the exon 1-intron 1 splice site, have been reported previously. The purpose of this study was to analyze the originally described family with XLCM (and other) for dystrophin mutations. METHODS AND RESULTS: Polymerase chain reaction (PCR) was used to amplify genomic DNA, and reverse-transcriptase PCR amplified cDNA from RNA obtained from heart and lymphoblastoid cell lines. Primers to the muscle promoter, brain promoter, and Purkinje cell promoter were designed, in addition to the exon 1 to exon 14 regions of dystrophin. Single-strand conformation polymorphism analysis was used for mutation detection, and DNA sequencing defined the mutation. Protein modeling was used for amino acid and secondary structure analysis. A missense mutation in exon 9 at nucleotide 1043 was identified that causes an alanine to be substituted for threonine, a highly conserved amino acid, at position 279 (T279A). This mutation results in a change in polarity in the evolutionarily conserved first hinge region (H1) of the protein and substitution of a beta-sheet for alpha-helix in this portion of the protein, destabilizing the protein. CONCLUSIONS: A novel missense mutation in exon 9 of dystrophin causing an abnormality at H1 leads to the cardiospecific phenotype of XLCM.