Haim-Munk Syndrome Health Article

Definition

Haim-Munk syndrome is an extremely rare genetic disorder similar to Papillion-Lefevre syndrome. Features include callous patches of skin on the palms of the hands and the soles of the feet, long pointy fingers, and degeneration of the tissues that surround and support the teeth.

Description

Haim-Munk syndrome is characterized by red, scaly thick patches of skin on the palms of the hands and soles of the feet (palmoplantar hyperkeratosis) that are apparent at birth along with frequent pus-producing (pyogenic) skin infections, overgrowth of the fingernails and toenails (onychogryphosis), and degeneration of the gums and bone surrounding the teeth (periodontosis) beginning in childhood. The severe and ongoing periodontosis usually causes the baby teeth to fall out prematurely, and often results in the loss of the permanent adult teeth as well.

In 1965, researchers Haim and Munk reported findings similar to Papillion-Lefevre syndrome in four siblings from an inbred Jewish family that originated from Cochin, India, on the Malabar Coast and later migrated to Israel. Features that are alike in both Papillion-Lefevre syndrome and Haim-Munk syndrome include skin abnormalities and severe periodontitis. These disorders are considered alternate forms of the same genetic mutation. There are a number of additional features reported in Haim-Munk syndrome that include long, thin, pointed fingers (arachnodactyly), bone loss in the fingers or toes (acroosteolysis), abnormal changes of the nails, and a claw-like deformity of the hands.

Haim-Munk syndrome is also known as Cochin Jewish disorder or congenital keratosis palmoplantaris.

Genetic profile

Haim-Munk syndrome is a homozygous expression of an autosomal recessive trait. Among palmoplantar keratoderma disorders, only Papillion-Lefevre syndrome and Haim-Munk syndrome are associated with the premature loss of teeth. It is suspected that Haim-Munk syndrome could be genetically different from common forms of palmoplantar keratoderma that are linked to the cytokeratin gene families.

Preliminary findings suggest that DNA markers other than keratin genes are responsible for the Haim-Munk syndrome. In 1997, genotype data in affected individuals found that the gene mutations in Haim-Munk syndrome were not due to a gene defect in either type I or type II keratin gene clusters on chromosomes 12 and 17, markers common to other palmoplantar keratoderma conditions.

Because Papillion-Lefevre syndrome and Haim-Munk syndrome present different symptoms than palmoplantar keratoderma disorders, both genetic syndromes are thought to be related to specific bacterial infections in those with palmoplantar keratoderma.

The cause of Papillion-Lefevre syndrome is a mutation in the cathepsin C gene resulting in periodontal disease and palmoplantar keratosis. Haim-Munk syndrome is thought to be a variant clinical expression of Papillion-Lefevre syndrome that is caused by defects in the cathepsin C gene as well.

A study in 2000 reported a mutation of cathepsin C (exon 6, 2127AfiG) that changes a highly conserved amino acid in the cathepsin C peptide. This suggests that Haim-Munk syndrome and Papillion-Lefevre syndrome are alternate forms of defects in the cathepsin C gene. The study also notes that the basis for the difference in clinical expression (symptoms) of these two syndromes caused by the mutated cathepsin C gene is not known.