Cystic fibrosis

 

Cystic fibrosis is our region’s most common autosomal recessive genetic disorder (this means that there must be a mutation in both copies of the gene pair for the disease to develop). It affects one in 3500 children in Europe. Cystic fibrosis is characterised by a mutation of a gene (CFTR) that codes for a protein responsible for the transport of chloride across cell membranes. Chloride cannot circulate normally and this results in thick, viscous mucosal secretions on the surfaces of the lungs and digestive system. The secretions accumulate and cause obstructions that may become infected. The disease affects the lungs, liver and other organs such as the pancreas (insulin-dependent diabetes), reproductive organs (fertility problems), and upper respiratory tract (nasal polyposis). In general, treatment focuses on the lungs and must include daily physiotherapy and hospitalisation for antibiotic therapy when secretions contain bacteria.

The liver may also be affected by the increased viscosity of bile caused by the abnormal CFTR protein in the bile ducts. The accumulation of viscous bile causes multiple obstructions of the bile ducts and may even result in cirrhosis. Cirrhosis makes it difficult for blood to flow through the liver, which means that blood accumulates in the intraabdominal organs. This is known as portal hypertension and has the following symptoms: increase in the size of the abdomen, poor weight gain and – in the most advanced cases – the risk of bleeding in the digestive tract. In rare cases, the liver damage associated with cystic fibrosis may be accompanied by a yellowing of the skin (jaundice) or hepatic insufficiency.

Cystic fibrosis is diagnosed by means of a sweat test to assess whether there is an increased concentration of chloride excreted in sweat; the diagnosis may be confirmed by genetic testing for the CFTR mutation.

Cystic fibrosis has no cure. Treatment aims at managing the disease and includes pulmonary treatment (antibiotic therapy, physiotherapy), cholestasis treatment (fat-soluble vitamins, ursodeoxycholic acid) and pancreatic enzyme replacement therapy for pancreatic damage. Depending on clinical findings, transplantation may be suggested: either a lung transplant, or a liver transplant, or a double transplant of both organs. A liver transplant will cure the liver-related aspects of the genetic disorder, which means that there will be no recurrence of the liver disease in the graft. However, the pulmonary and endocrine damage will remain after liver transplantation and will require the same treatment as before the transplant.

Dr. Natalie Rock
Octobre 2014