Classic Respiratory Disease but Atypical Diagnostic Testing Distinguishes Adult Presentation of Cystic Fibrosis

An overview of international literature from cystic fibrosis registries. Part 4: Update 2011

“…Keating et al [46] provided a detailed analysis of adult (N 18 years of age) presentation of CF from CFFR data. Adults showed the commonly described CF respiratory features (PA infection and reduced lung function), but had lower sweat chloride values and lower frequency of F508del mutation with a higher proportion of the class IV or V CFTR mutations.…”

Effects of Gender and Age at Diagnosis on Disease Progression in Long-term Survivors of Cystic Fibrosis

“…A second cohort is composed of patients diagnosed in adulthood, primarily due to the existence of CFTR mutations that afford partial function of the gene (5,6), resulting in a variable phenotype with a later onset of clinically significant symptoms (7)(8)(9)(10). Patients with an adult diagnosis (AD) of CF typically have milder lung disease than age-matched patients with a childhood diagnosis (CD) (11)(12)(13) and are predominantly pancreatic sufficient (PS) (11,12,14) or have recurrent pancreatitis (15,16). In both cohorts obstructive azoospermia in males is common, and may be the clinical feature that leads to diagnosis as an adult (17,18).…”

“…On occasion, laboratory testing may be inconclusive as sweat chloride testing is neither sensitive nor specific for the nonclassic phenotype (17,19), and genetic testing may reveal rare CFTR mutations with variable or unknown consequences (4). But in most cases, the diagnosis can be made with certainty, and progressively larger and older cohorts of AD patients have been reported by CF centers worldwide (3,(11)(12)(13)(14)(20)(21)(22).…”

Diagnosis of Cystic Fibrosis in Adults

“…Between 2001 and 2005, 9.0% of new diagnoses of CF were made in adults, compared with 7.7% between 1995 and 2000. 7 Approximately 90% of new cases of CF in both children and adults are identified among whites. More females than males are diagnosed as adults, unlike what is observed in childhooddiagnosed CF.…”

“…7 DF508 compound heterozygosity occurs frequently in the adult-diagnosed CF population, comprising 58% of observed genotypes, but 18% of adult-diagnosed patients do not possess a DF508 allele. 7 Nasal Potential Difference (NPD) Testing NPD testing has long been utilized as a research tool to assess CFTR function, and several CF centers use it as an aid in the diagnosis. A nasal electrode is placed on the nasal mucosa to allow for the measurement of electrical potentials across the mucosa, and the nasal mucosa is bathed in a series of solutions.…”