The nucleotide substitutions were discovered in the late 1990s by classical linkage analysis and are now known as p.R122H and p.N29I respectively, according to the amino acid substitution and position in the protein sequence. These mutations are rarely identified in general screens of patients with idiopathic disease and the phenotype of p.R122H and p.N29I is now well characterised with the p.A16V mutation recently characterised for the first time. There are many other rare mutations or polymorphisms of PRSS1 which remain less well understood and not all HP families have had the responsible genetic mutation identified. The mechanism by which these genetic mutations cause pancreatitis is not yet known; but is likely to be the result of increased autoactivation or reduced deactivation of trypsinogen. However, a novel mechanism has recently been identified in a p.R116C kindred. Diagnosis
Families are defined as having HP, if the phenotype is consistent with highly penetrant autosomal dominant inheritance. In simple terms, this would require two or more first degree relatives (or three or more second degree relatives) to have unexplained recurrent-acute or chronic pancreatitis in two or more generations. It is an autosomal dominant disease with penetrance that is generally accepted to be ≈80%. Management
Treatment of HP resemble that of chronic pancreatitis of other causes. Treatment focuses on enzyme and nutritional supplementation, pain management, pancreatic diabetes, and local organ complications, such as pseudocysts, bile duct or duodenal obstruction. (PMC1774562)

Prognosis
A 2009 study which followed 189 patients found no excess mortality despite the increased risk of pancreatic cancer. References


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Juvenile hyaline fibromatosis (also known as "Fibromatosis hyalinica multiplex juvenilis," "Murray–Puretic–Drescher syndrome") is a very rare, autosomal recessive disease due to mutations in capillary morphogenesis protein-2 (CMG-2 gene). It occurs from early childhood to adulthood, and presents as slow-growing, pearly white or skin-colored dermal or subcutaneous papules or nodules on the face, scalp, and back, which may be confused clinically with neurofibromatosis. The World Health Organization, 2020, reclassified the papules and nodules that occur in juvenile hyaline firbromatosis as one of the specific benign types of tumors in the category of fibroblastic and myofibroblastic tumors. Presentation
This condition is characterised by abnormal growth of hyalinized fibrous tissue with cutaneous, mucosal, osteoarticular and systemic involvement. Clinical features include extreme pain at minimal handling in a newborn, gingival hypertrophy, subcutaneous nodules, painful joint stiffness and contractures, muscle weakness and hypotonia. Genetics
This condition is due to mutations in the anthrax toxin receptor-2 (ANTXR2) gene. This gene is also known as capillary morphogenesis protein-2. This gene is located on the long arm of chromosome 4 (4q21.21). Management
There is no presently known curative treatment for this condition.Management is supportive

Prognosis
This is very poor with a median age at death of 15 months. Epidemiology
84 cases have been reported as of 2018. See also
List of cutaneous conditions

References


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