Hereditary Pancreatitis Relateed To PRSS1 Mutations
What is PRSS1-related hereditary pancreatitis?
Chronic pancreatitis of genetic origin due to mutations of the PRSS1 gene (serine protease 1) which codes for cationic trypsinogen. Transmission is autosomal dominant, penetrance is high but incomplete (> 80%). Prevalence is 6/100,000.
The mutation provokes an alteration of a self-cleavage site of the trypsin molecule. As it accumulates, trypsin activates the pancreatic enzymatic cascade in an early, unsuitable manner around the acinar cells, thus provoking repeated, acute pancreatitis.
How is it diagnosed ?
Two circumstances are evocative: young age at the start of symptoms or a family history of pancreatitis.
An analysis for mutation of the PRSS1 gene is performed after the patient's written consent is obtained.
What is its specific treatment ?
There is no specific treatment for chronic hereditary pancreatitis. In particular, there is no gene therapy. Treatments are above all symptomatic (pain care) and related to complications. In all cases, treatments must be multi-disciplinary, and social and psychological dimensions must always be taken into account.
Medical treatment is above all symptomatic, and the whole range of analgesics for WHO steps 1, 2 or 3 must be used as needed. However, care must be taken in case of long-term use of opioids (chronic usage > 6 months). They are thus of limited interest, and there is a real risk of dependence and social withdrawal (particularly in teenage patients). All alternatives must thus be envisaged: relaxation therapy, hypnosis, treatments of neuropathic pain (pregabalin, etc.), antidepressants, feeding exclusively by tube for four weeks during inflammatory phases in order to break the pain cycle, endoscopy, surgery, etc. It is essential:
- to obtain suitable health and diet advice to minimise the risk of flare-ups: to stop smoking, limit alcohol consumption, follow a balanced diet with limited consumption of cooked fats (fried foods, etc.) ;
- take an annual test for diabetes, exocrine pancreatic insufficiency and cholestasis. The risk of occurrence of pancreatic adenocarcinoma is increased with PRSS-related hereditary pancreatitis, in particular in smokers. This justifies testing starting at age 40 with an annual MRI of the pancreas..
Genetic Pancreatitis Related To SPINK1 Mutations
What is SPINK1-related genetic pancreatitis?
Pancreatitis with autosomal recessive transmission favoured by mutations of the SPINK1 gene (Serine Protease Inhibitor Kazal type 1) coding for the inhibitor of cationic trypsinogen.
Prevalence is 10/100,000.
The alteration of SPINK1 is not the sole cause of pancreatitis. It is one factor that is combined with other factors, both environmental and genetic (CFTR, PRSS1).
How is it diagnosed?
The diagnosis of a SPINK1 mutation is done via genetic testing after getting the patient's written consent.
Genetic Pancreatitis Related To CTRC Mutations
What is CTRC-related genetic pancreatitis?
Pancreatitis with autosomal recessive transmission favoured by mutations of the CTRC gene (Chymotrypsin C). The alteration of CTRC is not the sole cause of pancreatitis. It is a facilitating factor in repeated pancreatitis in the heterozygote state due to loss of its protective function (chymotrypsin C in its normal state enables intra-acinar breakdown of trypsin). Prevalence is one to nine per 100,000.
How is it diagnosed?
The diagnosis of a CTRC mutation is done via genetic testing after getting the patient's written consent.
Genetic Pancreatitis Related To CFTR Mutations
What is CFTR-related genetic pancreatitis?
Pancreatitis with autosomal recessive transmission favoured by mutations of the CFTR gene (Cystic Fibrosis Transmembrane Conductance Regulator), coding for the chloride channels of ductal cells.
This is a factor causing a predisposition to pancreatitis, even in the absence of patent cystic fibrosis.
Prevalence is one to nine per 100,000.
How is it diagnosed?
The diagnosis of a CFTR mutation is done via genetic testing after getting the patient's written consent.
Sources: Reference Centre for Rare Pancreatic Diseases and Disorders
Relevant reference centre: PaRaDis
Association pour les pancréatites chroniques héréditaires (French Chronic Hereditary Pancreatitis Association): A.P.C.H