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14 Cards in this Set

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Cystic Fibrosis: Clinical Features
Chronic pulmonary disease

Exocrine pancreatic insufficiency
Failure to thrive, meconium ileus in infants

Sinusitis, nasal polyps

Infertility in males

Elevated sweat electrolyte levels
Laboratory Diagnosis and Screening of Cystic Fibrosis
Sweat testing
Immunoreactive trypsin test (IRT)

DNA analysis
Cystic Fibrosis Carrier Frequencies in Various American Ethnic/Racial Populations
European Caucasian=1/29
Ashkenazi Jewish=1/29
Hispanic American=1/46
African American=1/65
Asian American=1/90
The Cystic Fibrosis Gene: Vital Statistics
 Complete gene locus spans 250 kb

27 exons

Mature mRNA of 6500 bases

Encodes an ion channel of 1480 amino acids (CFTR)

Three-nucleotide deletion of codon 508 (phe) in 70%
Delta F508
Shorthand for CF
Deletion+ Phenylalenine +codon #
most common recessive leathal disorder in North America
CF
Deletion+ Phenylalenine +codon #
about 24 possible mutations with CF
diversity of mutations
ETHICAL ISSUES IN CYSTIC FIBROSIS MUTATION SCREENING
Suboptimal test sensitivity
Ethnic differences
Education and counseling
Anxiety and stigmatization Informed consent Confidentiality
Insurability
Genetic and clinical burden
Abortion
R117H CF mutation
This mutation just causes male infertility
Preimplantation Genetic Diagnosis
Know mutation in both man & woman – start until blastocyst- test cell – implant in mom if negative – if positive throw out blastocyst
Potential Specimen Sources for Preimplantation Diagnosis
Spermatozoa
Oocytes
First polar body
Early embryonic cleavage cells
Blastomeres
NIH 1997 press release
Testing for CF should be offered to all pregnant couples
With 2 CF carrier parents what are the chances of:
1)Unaffected non-carrier
2)Unaffected carrier
3)Affected
1)25%
2)50%
3)25%
SUMMARY OF ACMG RECOMMENDATIONS FOR POPULATION-BASED CYSTIC FIBROSIS CARRIER SCREENING
1. Testing should be offered to Caucasians and Ashkenazi Jews, and made available to all other ethnic groups.
2. Either simultaneous or sequential couple screening may be used, as long as results are given to both partners.
3. A universal, pan-ethnic core mutation panel should be used, consisting of:
- 25 mutations
- 3 exonic polymorphisms as reflex tests
- 5/7/9T intronic polymorphism as reflex test only if R117H is positive