MedGen

Ivacaftor is the first FDA-approved drug designed to target a specific defect of the CFTR protein found in a subset of Cystic fibrosis (CF) patients. Hundreds of different variants within the CFTR gene have been identified. The G551D variant (rs75527207 G>A) results in defective gating at the plasma membrane and, in combination with another disease-causing CFTR allele, can result in CF disease phenotypes. Ivacaftor is designed to potentiate G115D-CFTR to improve symptoms in CF patients who carry this variant. Therapeutic guidelines for ivacaftor based on CFTR genotype have been published in Clinical Pharmacology and Therapeutics by the Clinical Pharmacogenetics Implementation Consortium (CPIC) and are available on the PharmGKB website. [from PharmGKB]

Bronchiectasis with or without elevated sweat chloride-1 (BESC1) is characterized by dilation of the airways arising from chronic bronchial inflammation accompanied by chronic cough, purulent sputum, and recurrent respiratory tract infections. Severity is variable, and some patients may be identified in adulthood and have normal respiratory function (Sheridan et al., 2005, Fajac et al., 2008). Genetic Heterogeneity of Bronchiectasis with or without Elevated Sweat Chloride Bronchiectasis with or without elevated sweat chloride-2 (BESC2; 613021) is caused by mutation in the gene encoding the alpha subunit of the epithelial sodium channel (SCNN1A; 600228) on chromosome 12p13, and BESC3 (613071) is caused by mutation in the gene encoding the gamma subunit (SCNN1G; 600761) on chromosome 16p12. Bronchiectasis and elevated sweat chloride associated with pancreatic exocrine dysfunction and infertility are also features of cystic fibrosis (CF; 219700), which is caused by mutation in the CFTR gene (602421). [from OMIM]

PRSS1-related hereditary pancreatitis (HP) is characterized by episodes of acute pancreatitis (AP) and recurrent acute pancreatitis (RAP: >1 episode of AP), with frequent progression to chronic pancreatitis (CP). Manifestations of acute pancreatitis can range from vague abdominal pain lasting one to three days to severe abdominal pain lasting days to weeks and requiring hospitalization. [from GeneReviews]

Cystic fibrosis (CF) is a multisystem disease affecting epithelia of the respiratory tract, exocrine pancreas, intestine, hepatobiliary system, and exocrine sweat glands. Morbidities include recurrent sinusitis and bronchitis, progressive obstructive pulmonary disease with bronchiectasis, exocrine pancreatic deficiency and malnutrition, pancreatitis, gastrointestinal manifestations (meconium ileus, rectal prolapse, distal intestinal obstructive syndrome), liver disease, diabetes, male infertility due to hypoplasia or aplasia of the vas deferens, and reduced fertility or infertility in some women. Pulmonary disease is the major cause of morbidity and mortality in CF. [from GeneReviews]

Cystic fibrosis (CF) is a multisystem disease affecting epithelia of the respiratory tract, exocrine pancreas, intestine, hepatobiliary system, and exocrine sweat glands. Morbidities include recurrent sinusitis and bronchitis, progressive obstructive pulmonary disease with bronchiectasis, exocrine pancreatic deficiency and malnutrition, pancreatitis, gastrointestinal manifestations (meconium ileus, rectal prolapse, distal intestinal obstructive syndrome), liver disease, diabetes, male infertility due to hypoplasia or aplasia of the vas deferens, and reduced fertility or infertility in some women. Pulmonary disease is the major cause of morbidity and mortality in CF. [from GeneReviews]