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Margaret W Leigh

Publications and source records attributed to Margaret W Leigh.

10 recordsLinked to original sources
PubMed2006

Mutations of DNAI1 in primary ciliary dyskinesia: evidence of founder effect in a common mutation.

RATIONALE: Primary ciliary dyskinesia (PCD) is a rare, usually autosomal recessive, genetic disorder characterized by ciliary dysfunction, sino-pulmonary disease, and situs inversus. Disease-causing mutations have been reported in DNAI1 and DNAH5 encoding outer dynein arm (ODA) proteins of cilia. OBJECTIVES: We analyzed DNAI1 to identify disease-causing mutations in PCD and to determine if the previously reported IVS1+2_3insT (219+3insT) mutation represents a "founder" or "hot spot" mutation. METHODS: Patients with PCD from 179 unrelated families were studied. Exclusion mapping showed no linkage to DNAI1 for 13 families; the entire coding region was sequenced in a patient from the remaining 166 families. Reverse transcriptase-polymerase chain reaction (RT-PCR) was performed on nasal epithelial RNA in 14 families. RESULTS: Mutations in DNAI1 including 12 novel mutations were identified in 16 of 179 (9%) families; 14 harbored biallelic mutations. Deep intronic splice mutations were not identified by reverse transcriptase-polymerase chain reaction. The prevalence of mutations in families with defined ODA defect was 13%; no mutations were found in patients without a defined ODA defect. The previously reported IVS1+2_3insT mutation accounted for 57% (17/30) of mutant alleles, and marker analysis indicates a common founder for this mutation. Seven mutations occurred in three exons (13, 16, and 17); taken together with previous reports, these three exons are emerging as mutation clusters harboring 29% (12/42) of mutant alleles. CONCLUSIONS: A total of 10% of patients with PCD are estimated to harbor mutations in DNAI1; most occur as a common founder IVS1+2_3insT or in exons 13, 16, and 17. This information is useful for establishing a clinical molecular genetic test for PCD.

Adolescent↗
PubMed2006

Physiologic, bronchoscopic, and bronchoalveolar lavage fluid findings in young children with recurrent wheeze and cough.

Assessing airway disease in young children with wheeze and/or cough is challenging. We conducted a prospective, descriptive study of lung function in children <3 years old with recurrent wheeze and/or cough, who had failed empiric antiasthma and/or antireflux therapy and subsequently underwent flexible bronchoscopy. Our goals were to describe radiographic, anatomical, microbiological, and physiological findings in these children, and generate hypotheses about their respiratory physiology. Plethysmography and raised-volume rapid thoracoabdominal compression (RVRTC) techniques were performed prior to bronchoscopy. Mean Z-scores (n = 19) were -1.34 for forced expiratory volume at 0.5 sec (FEV(0.5)), -2.28 for forced expiratory flows at 75% of forced vital capacity (FVC) (FEF(75)), -2.25 for forced expiratory flows between 25-75% of FVC (FEF(25-75)), 2.53 for functional residual capacity (FRC), and 2.23 for residual volume divided by total lung capacity (RV/TLC). Younger, shorter children had markedly depressed FEF(75) and FEF(25-75) Z-scores (P = 0.002 and P = <0.001, respectively). As expected, lower airway anatomical abnormalities, infection, and inflammation were common. Elevated FRC was associated with anatomical lower airway abnormalities (P = 0.03). FVC was higher in subjects with neutrophilic inflammation (P = 0.03). There was no association between other physiologic variables and bronchoscopic/bronchoalveolar lavage fluid findings. Half of those with elevated RV/TLC ratios (Z-score >2) had no evidence of chest radiograph hyperinflation. We conclude that in this population, plethysmography and RVRTC techniques are useful in identifying severity of hyperinflation and airflow obstruction, and we hypothesize that younger children may have relatively small airways caliber, significantly limiting airflow, and thus impairing secretion clearance and predisposing to lower airway infection.

Bronchoalveolar Lavage Fluid↗
PubMed2006

Are lower airway or throat cultures predictive of sinus bacteriology in cystic fibrosis?

The choice of antibiotics for sinusitis in children with cystic fibrosis (CF) is empirical or based on lower airway cultures, because sinus cultures are difficult to obtain. The aim of this study was to identify the main organisms cultured from CF children with chronic sinusitis, and to evaluate the concordance of concomitant sinus, oropharyngeal swab (OP), and bronchoalveolar lavage fluid (BALF) cultures. OP and BALF cultures were done preoperatively, and sinus cultures were obtained during clinically indicated sinus surgery. The genetic identity of the bacteria was compared if the same organisms were present in upper and lower airway cultures. In total, 45 paired sinus-BALF cultures from 31 patients were included. Twenty-four of these had matched OP cultures. The mean age of patients was 9.5 +/- 4.3 years, and 19 patients were DeltaF508 homozygous. Bacterial sinus infection was present in 96%, caused by S. aureus (49%), P. aeruginosa (42%), and H. influenzae (22%). The diagnostic accuracy of BALF or OP cultures was low in predicting sinus infection, particularly at younger ages. Positive and negative predictive values (PPV and NPV) of BALF for P. aeruginosa infection were 65% and 67%, and for S. aureus, 76% and 63%, respectively. Predictive values for OP cultures were similar. Bacterial species were the same in sinus and OP or BALF samples of 12 patients of these bacteria 83% showed genetic identity. We conclude that S. aureus is an important pathogen in pediatric CF sinusitis, and that BALF or oropharyngeal cultures are poor predictors for organisms present in the sinuses.

Adolescent↗
PubMed2005

Nontuberculous mycobacterial infection in young children with cystic fibrosis.

Although nontuberculous mycobacteria (NTM) are recognized pathogens in adolescent and adult patients with cystic fibrosis (CF), the role of NTM in younger CF patients is not well-defined. To explore NTM infection in CF patients less than 12 years old, a retrospective review was performed. Prevalence was estimated from routine mycobacterial cultures of bronchoalveolar lavage (BAL) specimens collected over a 3-year period. NTM-positive cultures were obtained from 9 of 258 BALs collected from 7 of 114 different patients (5 months to 11 years of age). Further data were acquired from microbiological and clinical records of all pediatric patients with CF over a 10-year period. A total of 17 patients had at least one positive mycobacterial culture at less than 12 years of age, 5 of whom had positive cultures before age 5. The most commonly identified organisms were Mycobacterium avium-complex and Mycobacterium abscessus. Of the 17 patients, 10 met American Thoracic Society (ATS) microbiological criteria for mycobacterial disease, and 7 did not. The two groups did not differ with respect to age, gender, or presence of other respiratory pathogens. Patients who met ATS microbiological criteria for disease were more likely to have positive smears for acid-fast bacilli and grow Mycobacterium abscessus from culture. These patients also had a greater decline in lung function over time than patients who did not meet the microbiologic criteria. These data suggest that NTM represent a clinically significant pathogen, even in young patients with cystic fibrosis.

Anti-Bacterial Agents↗
PubMed2003

Primary ciliary dyskinesia: diagnostic and phenotypic features.

Primary ciliary dyskinesia (PCD) is a genetic disease characterized by abnormalities in ciliary structure/function. We hypothesized that the major clinical and biologic phenotypic markers of the disease could be evaluated by studying a cohort of subjects suspected of having PCD. Of 110 subjects evaluated, PCD was diagnosed in 78 subjects using a combination of compatible clinical features coupled with tests of ciliary ultrastructure and function. Chronic rhinitis/sinusitis (n = 78; 100%), recurrent otitis media (n = 74; 95%), neonatal respiratory symptoms (n = 57; 73%), and situs inversus (n = 43; 55%) are strong phenotypic markers of the disease. Mucoid Pseudomonas aeruginosa (n = 12; 15%) and nontuberculous mycobacteria (n = 8; 10%) were present in older (> 30 years) patients with PCD. All subjects had defects in ciliary structure, 66% in the outer dynein arm. Nasal nitric oxide production was very low in PCD (nl/minute; 19 +/- 17 vs. 376 +/- 124 in normal control subjects). Rigorous clinical and ciliary phenotyping and measures of nasal nitric oxide are useful for the diagnosis of PCD. An increased awareness of the clinical presentation and diagnostic criteria for PCD will help lead to better diagnosis and care for this orphan disease.

Adult↗
PubMed2003

Investigation of the possible role of a novel gene, DPCD, in primary ciliary dyskinesia.

Primary ciliary dyskinesia (PCD) is an autosomal recessive disease caused by mutations that affect the proper function of cilia. Recently, deletion of DNA polymerase lambda (Poll) in mice produced a phenotype characteristic of PCD (Kobayashi et al., 2002, Mol. Cell. Biol. 22:2769-2776). Because it is unclear how a mutation in a DNA polymerase would result in a specific defect in axonemes, the targeting construct was examined further. Analysis of the genomic region surrounding the Poll gene revealed an uncharacterized gene, named Dpcd, that is predicted to be transcribed from the opposite strand relative to Poll. The deletion of Poll would also remove the first exon of Dpcd. Because it is possible that the PCD phenotype observed is due to the absence of either gene, the expression of these genes during ciliogenesis of human airway epithelial cells was examined. Northern analysis demonstrated that DPCD expression increases during ciliated cell differentiation; the expression of POLL decreases. To examine directly whether DPCD is mutated in cases of human PCD, the complete coding sequence of DPCD was sequenced from 51 unrelated PCD patients. No disease-causing mutations were confirmed; however, one variant could not be excluded. Therefore, DPCD remains a novel candidate gene for PCD.

Bronchi↗
PubMed2003

Bronchoalveolar lavage fluid surfactant protein-A and surfactant protein-D are inversely related to inflammation in early cystic fibrosis.

The pulmonary collectins surfactant protein (SP)-A and SP-D play important roles in innate lung defense, enhancing opsonization of microbes and limiting lung inflammatory responses. To quantify relationships among collectins, bacteria, and inflammation in early cystic fibrosis (CF) airway secretions, bronchoalveolar lavage fluids (BALFs) were collected from children undergoing clinically indicated bronchoscopy. Quantitative bacteriology, differential cell counts, and ELISA for SP-A and SP-D were assessed. Significantly increased numbers of neutrophils relative to bacteria were noted in BALF from CF compared with non-CF subjects. Although SP-A levels tended to be lower in CF compared with non-CF, this was only significant in the presence of bacterial infection. Among CF patients, SP-A concentrations in BALF were inversely related to inflammation, bacterial colony-forming units per milliliter, and age. SP-D levels were significantly decreased in CF patients, and SP-D was rarely detectable in the presence of infection. Among CF patients, SP-D correlated inversely with inflammation and bacterial colony-forming units per milliliter, and there was decreased immunostaining of BALF cells for SP-D in CF. Immunohistochemistry of CF autopsy lung sections for SP-A and SP-D confirmed their paucity at sites of infection and inflammation. We conclude that relative collectin deficiency occurs early in CF airways and is inversely related to inflammation in CF airways.

Analysis of Variance↗
PubMed2003

Primary ciliary dyskinesia.

Primary ciliary dyskinesia (PCD) is an inherited disorder characterized by impaired ciliary function that leads to an array of clinical manifestations including chronic bronchitis, chronic sinusitis, chronic otitis media, situs inversus (in approximately 50% of cases), and infertility. The underlying genetic and molecular defects have not been defined. Molecular genetic studies have demonstrated multiple gene loci. In a few families, defects in genes encoding ciliary dynein proteins have been identified. PCD is an interesting disease to compare with cystic fibrosis (CF) because both are airway diseases associated with impaired mucociliary clearance and with chronic infection of the airways leading to bronchiectasis as well as chronic infection of the sinuses that may be associated with nasal polyposis. The progression of the lower airway disease appears less rapid in PCD. Unlike CF, PCD is commonly associated with chronic otitis media, respiratory problems during the neonatal period, and situs inversus, suggesting that ciliary function is also important for clearing fluid/bacteria from the middle ear, for clearing fluid from the fetal lung during the transition to an air-filled neonatal lung, and for directing laterality of organs during embryonic development. The management for PCD lung disease is similar to that for CF and other diseases with chronic bronchitis leading to bronchiectasis.

Journal Article↗