Disease knowledge in a high-risk population for cystic fibrosis

Highlighting the impact of cascade carrier testing in cystic fibrosis families

BACKGROUND

Cascade carrier testing within cystic fibrosis (CF) affected families offers relatives of CF patients the opportunity to know their status regarding the mutation that segregates within their family, and thus to make informed reproductive choices. As an Australian study has recently shown that this test seemed underused, we searched to assess uptake of this test in a European area where CF is common, and to report its public health implications.

METHODS

This study relied on 40 CF-affected families from western Brittany, France. Investigations included drawing of family trees and registration of carrier tests performed in those families.

RESULTS

Of the 459 relatives eligible for testing, 185 were tested, leading to an adjusted uptake rate of testing of 40.7% (95% CI: [34.1%; 47.3%]). The main predictors for having testing were being female (p=0.031) and having a high prior risk (p<0.001). Planning a pregnancy or expecting a child (reported in at least 38.4% of tested relatives) also appeared critical in choosing to be tested. Overall, carrier testing allowed to reassure more than 1/4 of the relatives and to detect five new 1-in-4 at-risk couples who then requested prenatal diagnosis.

CONCLUSIONS

This observational study assesses, for first time in Europe, uptake of CF cascade carrier testing within CF families, which is a critical tool to reassure non-carriers and to detect early new at-risk couples.

Paternity in men with cystic fibrosis: a retrospective survey in France

BACKGROUND

Because more patients reach adulthood, new questions as "what about having a child and/or paternity responsibility?" arose.

METHOD

We performed a retrospective investigation based on the French CF registry. The context of the paternity and the health status of fathers were recorded. A comparison with clinical status of non-father patients and a compilation of follow-up data to evaluate its impact were done.

RESULTS

Forty-eight men had 69 children. One fourth was said to be natural conceptions, 69% needed assisted reproduction techniques. No child had CF. Clinical status of men was satisfactory: mean BMI was 20.9 kg/m(2) and mean FEV(1) and FVC were 50.5% and 69.2% of predicted, respectively. When matched to CF non-fathers, few significant differences appeared. More non-fathers were F508del/F508del (p=0.03). Fathers' sputum cultures were positive for non-Pseudomonas aeruginosa strain (p=0.05), including Staphylococcus aureus (p=0.01). Mean age at diagnosis was higher, and based on minor evidence of sterility as first symptom leading to the diagnosis of CF (p=0.01) or aspergillosis (p=0.03). The 3-year follow-up showed no degradation of the clinical status.

CONCLUSION

Men having paternity responsibility over children did not differ from the CF male population and neither did it seem to have an impact on the disease course.

Parental attitudes to the identification of their infants as carriers of cystic fibrosis by newborn screening

AIM

To investigate parental attitudes to cystic fibrosis (CF) carrier detection of their infant by newborn screening (NBS).

METHODS

Data were collected from a postal questionnaire sent to parents of infants identified as CF carriers by NBS in 1996-1997 (inclusive) and 2001 in Victoria, Australia (n = 66).

RESULTS

Almost all parents remembered their child being identified as a CF carrier (97%: 1996/1997; 100%: 2001); yet the majority were unaware at the time that NBS could detect carriers (70%: 1996/1997; 49%: 2001). More parents in the later cohort reported having carrier testing compared with the earlier cohort (85% and 53% respectively) but recall was more uncertain in the earlier cohort when validated against health records. Cascade testing was not utilised frequently by other family members in either cohort. Residual risk of being a carrier if testing was negative was not well understood by parents. Some parents (28%: 1996/1997; 18%: 2001) had residual anxiety about the current health of their carrier child and their future reproductive decision making. Most parents were satisfied with the information provided to them at the time of the sweat test. Few differences were seen between the cohorts.

CONCLUSION

Although the NBS process for CF in Victoria is working efficiently for the majority of families whose infant is identified as a carrier there are areas that can be improved. We recommend that greater attention should be given to informing parents that a consequence of NBS is CF carrier detection and strategies to improve utilisation of cascade testing should be developed.