Newborn screening for cystic fibrosis

Isolated liver disease in a patient with a CFTR genotype F508del/12TG-5T and 470MV: A new face of an old disease

Today the knowledge of genotype-phenotype correlation in cystic fibrosis is enriched by the growing discoveries of new mutations of the CFTR gene. Although the combination of two severe mutations usually leads to the classic disease (pulmonary and pancreatic insufficiency, sterility, nasal polyposis), the presence of a complex genotype characterized by severe and milder mutations or polymorphism can cause a hidden disease, which is often asymptomatic at early ages. We report on a case of a 15 years old boy, in whom the only clinical signs of CF were chronic hypertransaminasemia and hyperbilirubinemia, and in whom it was demonstrated the presence of the mutations F508del associated with TG11-9T-470M in one allele and TG12-5T-470V in the other allele. Although a clear genotype-phenotype correlation for liver disease is still missing for CF patients, it is possible to state that this isolated clinical presentation could represent an unusual phenotype of CF, related to a complex genotype characterized by a severe mutation and one (or more) polymorphism.

Rectal prolapse and cystic fibrosis

Screening for cystic fibrosis (CF) is suggested in patients with rectal prolapse (RP). Little is known about the association between CF and RP in the era of newborn screening for CF. Our retrospective review showed that 3.6% of patients with RP had CF, and 3.5% of patients with CF had RP. No demographic or clinical factors appear to predict the likelihood of RP in patients with CF. Sweat chloride testing for patients with RP has a low yield in the era of newborn screening but may still need to be considered in children with RP to avoid missing the rare child with CF.

Newborn screening for cystic fibrosis in Serbia: a pilot study

BACKGROUND

We performed a pilot study of neonatal screening for cystic fibrosis (CF) in order to introduce it to the national screening program in Serbia.

METHODS

Immunoreactive trypsinogen (IRT) concentrations were analyzed in dried blood spot samples. Patients were recalled for repeated measurements in case of high IRT levels. Persisting high IRT levels resulted in DNA testing for the 29 most common mutations in the CF transmembrane regulator (CFTR) gene (IRT/IRT/DNA method). Sweat chloride measurements and clinical assessment were further performed for newly diagnosed patients.

RESULTS

Of 1000 samples, three were initially positive and were further analyzed for the presence of the most common CFTR mutations in the Serbian population. DNA analysis revealed two patients being homozygous for F508del mutation. One sample was false positive, as the genetic test proved to be negative and associated with normal sweat chloride concentration and unremarkable clinical presentation.

CONCLUSIONS

The results of our pilot study justified the expanding of the routine neonatal screening program in Serbia with CF. Data could be used in future in order to obtain accurate incidence of CF and carrier prevalence in our country.

Effects of immediate telephone follow-up with providers on sweat chloride test timing after cystic fibrosis newborn screening identifies a single mutation

OBJECTIVE

To assess whether reporting "possible cystic fibrosis (CF)" newborn screening (NBS) results via fax plus simultaneous telephone contact with primary care providers (PCPs) versus fax alone influenced 3 outcomes: undergoing a sweat chloride test, age at sweat chloride testing, and undergoing sweat testing before age 8 weeks.

STUDY DESIGN

This was a retrospective cohort comparison of infants born in Wisconsin whose PCP received a telephone intervention (n = 301) versus recent historical controls whose PCP did not (n = 355). Intervention data were collected during a longitudinal research and quality improvement effort; deidentified comparison data were constructed from auxiliary NBS tracking information. Parametric and nonparametric statistical analyses were performed for group differences.

RESULTS

Most infants (92%) with "possible CF" NBS results whose PCP lacked telephone intervention ultimately underwent sweat testing, underlining efficacy for fax-only reporting. Telephone intervention was significantly associated with improvements in the infants undergoing sweat testing at age ≤6 weeks and <8 weeks and a slight, statistically nonsignificant 3.5-day reduction in the infants' age at sweat testing. The effect of telephone intervention was greater for PCPs whose patients underwent sweat testing at community-affiliated medical centers versus those whose patients did so at academic medical centers (P = .008).

CONCLUSION

Reporting "possible CF" NBS results via fax plus simultaneous telephone follow-up with PCPs increases the rate of sweat chloride testing before 8 weeks of age, when affected infants are more likely to receive full benefits of early diagnosis and treatment.

Aquagenic wrinkling of the palms and the potential role for genetic testing

Aquagenic wrinkling of the palms (AWP) is a condition characterized by excessive wrinkling, palmar edema, and whitish papules accompanied by pain, pruritus, or discomfort after brief immersion of the hands in water. It is well documented to be associated with cystic fibrosis (CF), with several theories regarding the pathogenesis having been proposed. We report a case of two sisters with AWP in whom CF has not been diagnosed and review the literature on AWP and its association with CF and CF carrier status. Because diagnosis of mild forms CF or knowledge of an underlying CF genetic mutation is frequently unknown, identification of AWP may represent the only sign of such mutations. The dermatologist plays an integral role in early detection of AWP, and the importance of genetic testing in such patients cannot be overlooked. We recommend various measures to apply in clinical practice to ensure diagnosis and decrease morbidity and mortality in patients.

Psychosocial consequences of false-positive newborn screens for cystic fibrosis

This study was designed to develop a framework for understanding parents' perspectives about the psychosocial consequences of false-positive newborn screening (NBS) results for cystic fibrosis (CF). Through content analysis of interviews with 87 parents of 44 infants, we found that receipt of genetic information through NBS affected parents on intrapersonal and interpersonal levels within a relational family system. Repercussions included wondering about test accuracy, the child's health, and the future; gaining new perspectives and strengthening relationships; questioning paternity; wondering if other relatives had CF/were carriers; searching for the genetic source; sharing genetic information; supporting NBS; and feeling empathy for parents of affected children. We concluded that abnormal NBS results that involve genetic testing can have psychosocial consequences that affect entire families. These findings merit additional investigation of long-term psychosocial sequelae for false-positive results, interventions to reduce adverse iatrogenic outcomes, and the relevance of the relational family system framework to other genetic testing.

A tailored approach to family-centered genetic counseling for cystic fibrosis newborn screening: the Wisconsin model

This article describes the development of a tailored family-centered approach to genetic counseling following abnormal newborn screening (NBS) for cystic fibrosis (CF). A genetic counseling consortium reviewed research literature, selected theoretical frameworks, and incorporated counseling psychology micro skills. This innovative intervention integrated theories and empirically validated techniques. Pilot testing and parent feedback confirmed satisfaction with and feasibility of the approach designed to (a) minimize parents' distress, (b) facilitate parents' understanding, (c) increase parents' capacities to use genetic information, and (d) enhance parents' experiences with genetic counseling. Counselors engage in a highly interactive process of evaluating parents' needs and tailoring assessments and interventions that include a therapeutic environment, the family's emotional needs, parents' informational needs, and a follow-up plan. This promising new model is the first to establish a theory-driven, evidence-based standard for genetic counseling in the context of NBS for CF. Additional research will evaluate the model's efficacy in clinical practice.

Population based allele frequencies of disease associated polymorphisms in the Personalized Medicine Research Project

Background

There is a lack of knowledge regarding the frequency of disease associated polymorphisms in populations and population attributable risk for many populations remains unknown. Factors that could affect the association of the allele with disease, either positively or negatively, such as race, ethnicity, and gender, may not be possible to determine without population based allele frequencies.

Here we used a panel of 51 polymorphisms previously associated with at least one disease and determined the allele frequencies within the entire Personalized Medicine Research Project population based cohort. We compared these allele frequencies to those in dbSNP and other data sources stratified by race. Differences in allele frequencies between self reported race, region of origin, and sex were determined.

Results

There were 19544 individuals who self reported a single racial category, 19027 or (97.4%) self reported white Caucasian, and 11205 (57.3%) individuals were female. Of the 11,208 (57%) individuals with an identifiable region of origin 8337 or (74.4%) were German.

41 polymorphisms were significantly different between self reported race at the 0.05 level. Stratification of our Caucasian population by self reported region of origin revealed 19 polymorphisms that were significantly different (p = 0.05) between individuals of different origins. Further stratification of the population by gender revealed few significant differences in allele frequencies between the genders.

Conclusions

This represents one of the largest population based allele frequency studies to date. Stratification by self reported race and region of origin revealed wide differences in allele frequencies not only by race but also by region of origin within a single racial group. We report allele frequencies for our Asian/Hmong and American Indian populations; these two minority groups are not typically selected for population allele frequency detection. Population wide allele frequencies are important for the design and implementation of studies and for determining the relevance of a disease associated polymorphism for a given population.

Cystic fibrosis and transition to adult medical care

Transition of young adults with cystic fibrosis (CF) from pediatric to adult medical care is an important priority, because many patients are living well into their fourth decade, and by 2010 more than half of all people living with CF will be older than 18 years. Transition to adulthood, a developmental process of skill-building in self-management supported by the health system, is important for the successful transfer to adult CF care. The US Cystic Fibrosis Foundation has been proactive in preparing for increasing numbers of young adults in need of specialized adult-oriented care by creating specialized clinical fellowships for physician providers and mandating establishment of adult CF programs. Despite these initiatives, how to best facilitate transition and to define and measure successful outcomes after transfer to adult care remains unclear. Many adults with CF continue to receive care in the pediatric setting, whereas others transfer before being developmentally prepared. In this state-of-the-art review we provide context for the scope of the challenges associated with designing and evaluating health care transition for adolescents and young adults with CF and implications for all youth with special health care needs.

Visual DNA as a diagnostic tool

We report on the incorporation of the Visual DNA concept in a genotyping assay as a simple and straightforward detection tool. The principle of trapping streptavidin-coated superparamagnetic beads of micrometer size for visualization of genetic variances is used for PrASE-based detection of a panel of mutations in the severe and common genetic disorder of cystic fibrosis. The method allows a final investigation of genotypes by the naked eye and the output is easily documented using a regular hand-held device with an integrated digital camera. A number of samples were run through the assay, showing rapid and accurate detection using superparamagnetic beads and an off-the-shelf neodymium magnet. The assay emphasizes the power of Visual DNA and demonstrates the potential value of the method in future point-of-care tests.

CFTR allelic heterogeneity in Brazil: historical and geographical perspectives and implications for screening and counseling for cystic fibrosis in this country

The goal of the present study was to provide a complete and updated spectrum of cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene mutations in the Brazilian population combining all available in silico data for patients with CF in Brazil, including founder background and migration flow that consisted of the actual genetic pool of the Brazilian population. Information sources in international databases (PUBMED and SCIELO) were searched. The Brazilian population shows a wide variation in the frequency of CFTR mutations in states Rio Grande do Sul (RS), Santa Catarina (SC), Paraná (PR), São Paulo (SP), Rio de Janeiro (RJ), Minas Gerais (MG), Pará (PA) and Bahia (BA); this variation includes the most common mutation p.F508del. Apparently, this frequency variation is because of the different ethnic compositions. States such as SC and PR have a greater European admixture with almost 90% of CF alleles identified. In other states, such as BA, higher frequency of alleles that are common among African populations is seen. Overall, the CFTR mutational spectrum indicates the presence of European, African and Amerindian ethnic groups in the contemporary Brazilian CF patients. Here, we present an analysis of the CFTR allelic heterogeneity and discuss the origin of its genetic composition, in an attempt to provide improved perspective for the CF population screening in Brazil and genetic counseling.