<\/span><\/h2>\nHIDS is predominantly identified in populations in two areas of northern Europe, the Netherlands (more than 50% cases) and northern France. However, approximately 200 cases have been reported in various ethnic groups.<\/p>\n
HIDS symptoms usually begin before the age of 1 year with an average age of onset of 6 months. However, making the diagnosis is challenging and can often take many years.<\/p>\n
HIDS is inherited as a autosomal<\/span> recessive condition, i.e. two copies of the faulty gene<\/span> are inherited, one of each of the unaffected carrier<\/span> parents<\/p>\n<\/span>\nMolecular<\/span> biology and genetics<\/span><\/h3>\nThe MVK gene involved in HIDS is found in chromosome<\/span> 12 (12q24) and produces the enzyme<\/span> mevalonate kinase Mutations<\/span> In this gene, 75% have been reported in typical cases. V377I is the most common related disease mutation<\/span> reported. In HIDS, genetic mutations result in reduced enzyme activity, approximately 5-10% from normal. Mevalonic aciduria is a more serious and fatal form of this deficiency in which the enzyme activity is practically undetectable. (look down)<\/p>\nThe enzyme mevalonate kinase is involved in the isoprenoid pathway of cholesterol<\/span> biosynthesis. Enzymatic deficiency results in accumulation of mevalonic acid and increases interleukin<\/span> 1)<\/p>\n\n
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<\/span>HIDS Clinical Features<\/span><\/h2>\nthe acute<\/span> febrile<\/span> HIDS episodes begin in childhood. The clinical characteristics are:<\/p>\n\n- fever<\/li>\n
- non-migratory maculopapular<\/span> acne<\/li>\n
- headache<\/li>\n
- painful enlarged lymph nodes<\/span> in the neck<\/li>\n
- abdominal and joint pain<\/li>\n<\/ul>\n
Attacks last up to a week, longer than those of family<\/span> Mediterranean fever. They can reappear every 1-2 months.<\/p>\nThe characteristics of recurrent acute episodes of HIDS are described in the table below.<\/p>\n
\n\n\n| Symptom<\/span><\/th>\n | Characteristics<\/th>\n<\/tr>\n |
\n| Fever<\/td>\n | \n\n- more than 40C<\/li>\n
- previous chills and discomfort<\/span>\n<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n
\n| Acne<\/td>\n | \n\n- affects up to 80%<\/li>\n
- various presentations (see below)<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n
\n| Headache<\/td>\n | \n\n- unspecific<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n
\n| Enlarged lymph nodes in the neck<\/td>\n | \n\n- characteristic<\/li>\n
- bilateral<\/span><\/li>\n
- painful<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n
\n| Abdominal pain<\/td>\n | \n\n- serious<\/li>\n
- diarrhea and vomiting<\/li>\n
- peritonitis<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n
\n| Joint pain<\/td>\n | \n\n- \narthralgia<\/span> (pain) or arthritis<\/span> (swelling)<\/li>\n
- more common in young patients<\/li>\n
- affects large joints<\/li>\n
- \nsymmetrical<\/span>, polyarticular, non-destructive<\/li>\n
- symptoms occur with abdominal pain and settle slowly<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n
\n| Enlarged liver and spleen (hepatosplenomegaly<\/span>)<\/td>\n | \n\n- affects children's 50%<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n
\n| Tendinitis<\/td>\n | <\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/span>\nCutaneous<\/span> hids signs<\/span><\/h2>\nThe rash affects up to 80% of the patients. A quantity of skin rashes<\/span> or rashes have been described in this syndrome, and these resolve slowly after the febrile episode stabilizes.<\/p>\nThe skin rashes seen in HIDS are most commonly described as follows:<\/p>\n \n- small flat spots (macules<\/span>)<\/li>\n
- raised bumps (small papules<\/span> or bigger nodules<\/span>)<\/li>\n
- \n
measles-like rashmorbilliform<\/span>)<\/li>\n- acneurticarial<\/span>)<\/li>\n<\/ul>\n
Less common or rare skin presentations include:<\/p>\n \n- Henoch-Sch\u00f6nlein purple<\/span><\/li>\n
- erythema<\/span> elevatum diutinum<\/li>\n
- \npetechiae<\/span> (small bleeding or purple spots)<\/li>\n
- erythema nodosum<\/li>\n<\/ul>\n
Oral and \/ or vaginal aphthous ulcers<\/span> it affects the 50% of the patients.<\/p>\n<\/span>What triggers the attacks?<\/span><\/h2>\nAcute episodes can be caused by:<\/p>\n \n- Vaccines: More than 50% report at least one episode in childhood after immunization<\/li>\n
- Infection<\/span><\/li>\n
- Physical and emotional stress.<\/li>\n
- \nTrauma<\/span>, including surgery<\/li>\n<\/ul>\n
\n \n \n \n<\/div><\/div><\/div><\/div>\n <\/span>What is the likely outcome for patients?<\/span><\/h2>\nThere is a tendency to improve with age, with less frequent and less severe attacks in adulthood. Between episodes, health is normal.<\/p>\n A small subgroup of affected patients develops neurological abnormalities in adulthood, similar to mevalonic aciduria (see below).<\/p>\n Unlike familial Mediterranean fever, amyloidosis is rarely seen in HIDS, affecting less than 3%.<\/p>\n Life expectancy is usually normal, however this can be affected by renal<\/span> failure due to amyloidosis or serious infections.<\/p>\n<\/span>How is HIDS diagnosed?<\/span><\/h2>\nCharacteristic recurrent acute febrile seizures without an infectious clearing or autoimmune<\/span> cause, suggest the need for research.<\/p>\n<\/span>Clinical criteria<\/span><\/h3>\nIn addition to the febrile seizures described above, clinical diagnostic criteria should include:<\/p>\n | | | | | | | |