Hyperimmunoglobulinemia D with Periodic Fever Syndrome (HIDS): A Comprehensive Overview
Defining Hyper-IgD Syndrome (HIDS)
Hyperimmunoglobulinemia D with periodic fever syndrome (MIM 260920), commonly known as hyper-IgD syndrome or HIDS, is a rare hereditary autoinflammatory disorder. This syndrome manifests through recurrent episodes that include fever, skin rashes, significant abdominal pain, headaches, and the appearance of enlarged lymph nodes, typically presenting from infancy.
A more severe and potentially fatal form of this condition is mevalonic aciduria.
Epidemiology and Risk Factors for HIDS
HIDS is observed predominantly concentrated in two regions of Northern Europe: the Netherlands, where more than 50% of reported cases are located, and Northern France. Nevertheless, nearly 200 cases have been documented distributed across various ethnicities worldwide.
Generally, HIDS symptomatology emerges before the first year of life, with a median age of onset set at 6 months. However, establishing an accurate diagnosis is a complex process that frequently extends over several years.
HIDS is inherited in an autosomal recessive pattern, which implies that the individual must inherit two copies of the defective gene, one from each parent, who are generally unaffected carriers of the condition.
Molecular Biology and Genetic Basis
The MVK gene, associated with HIDS, is located on chromosome 12 (12q24) and is responsible for coding the mevalonate kinase enzyme. Mutations in this gene have been identified in approximately 75% of typical cases. The V377I mutation is the most commonly reported variant.
In HIDS patients, genetic alterations cause reduced enzyme activity, ranging between 5% and 10% of normal levels. Mevalonic aciduria represents the most severe presentation, where enzyme activity is practically undetectable (as will be detailed later).
The mevalonate kinase enzyme plays a crucial role in the isoprenoid pathway, essential for cholesterol biosynthesis. The resulting enzyme deficiency leads to the significant accumulation of mevalonic acid and a dangerous increase in interleukin 1 levels.
Detailed Clinical Manifestations of HIDS
The characteristic acute, febrile episodes of Hyper-IgD Syndrome begin to manifest during childhood. The main clinical features observed include:
- High fever.
- Presence of a non-migratory maculopapular rash.
- Intense headaches.
- Painful lymphadenopathy (enlargement of lymph nodes) in the cervical region.
- Significant abdominal and joint pain.
The average duration of these attacks extends up to one week, which is a longer period than observed in Familial Mediterranean Fever. These flares tend to recur every one or two months.
Below are the specific characteristics of acute and recurrent HIDS episodes detailed in the following descriptive table.
| Symptom | Characteristics |
|---|---|
| Periodic Fever |
|
To provide a complete understanding of HIDS, it is essential to investigate these clinical manifestations and their diagnostic management in depth.
| Clinical Manifestation | Relevant Details |
|---|---|
| Periodic Fever | Persistent low-grade fever with peaks lasting several days; preceding symptoms and malaise generalized malaise. |
| Skin rash | Affects up to 80% of cases; presents several clinical forms (described later). |
| Headache | Nonspecific in nature. |
| Cervical Lymphadenopathy | Characteristic presentation; it is bilateral., frequently painful. |
| Abdominal Pain | Can be severe, associated with diarrhea and vomiting; in rare cases, it may progress to peritonitis. |
| Arthralgias and Arthritis | Arthralgia (pain) or Rheumatoid (inflammation); more prevalent in young patients. Presentation symmetrical, polyarticular, and non-destructive. Joint symptoms generally coincide with abdominal pain and resolve slowly afterward. |
| Hepatomegaly and Splenomegaly | Enlargement of the liver and spleen (hepatosplenomegaly); present in approximately 50% of affected children. |
| Tendinitis |
Dermatological Signs in HIDS
Skin involvement is common, presenting in up to 80% of patients with HIDS. Various forms of rashes or eruptions have been documented in this syndrome, which tend to disappear gradually once the febrile episode has subsided. rashes o rashes in this syndrome, which tend to disappear gradually once the febrile episode has subsided.
The most frequent skin manifestations in HIDS include:
- Tiny flat lesions (macules).macules).
- Raised bumps (small papules or papules o nodules of larger size).
- Rash with measles-like characteristics (morbilliform).rash).
- Hives-like rash (urticarial).hives).
Among the less frequent or rare cutaneous presentations are:
- Henoch-Schönlein purpura (purpura).purpura).
- phenotypes Erythema elevatum diutinum.
- Petechiae (small hemorrhagic or purplish spots).
- Erythema nodosum.
Additionally, up to 50% of patients experience ulcers oral and/or vaginal aphthous ulcers. vaginal.
Triggers for Attacks
Acute symptomatic episodes of HIDS can be provoked by several identifiable elements, including:
- Vaccinations: More than 50% of individuals report at least one episode during childhood following vaccination.
- Infections.
- Significant stress, both physical and emotional.
- Trauma, including surgical procedures.
What is the Prognosis for HIDS Patients?
Generally, there is a favorable evolution with age; attacks tend to be less frequent and their severity decreases in adulthood. It is crucial to note that between acute episodes, the patient's general health remains normal.
However, a small subgroup of individuals suffering from this condition may develop or develop neurological abnormalities in adulthood, manifesting similarly to mevalonic aciduria (a condition discussed in other contexts).
Unlike Familial Mediterranean Fever, the presentation of amyloidosis is exceptional in HIDS, affecting less than 3% of cases. Life expectancy is usually normal for most patients, although...
This may be affected by renal failure due to amyloidosis or severe infections. Unlike other serious.
Diagnosis of HIDS (Mevalonate Kinase Deficiency)
Recurrent acute febrile attacks, especially when lacking a clear infectious or defect underlying cause, require an exhaustive diagnostic evaluation.
Essential Clinical Criteria
In addition to documenting the characteristic recurrent febrile episodes, the fundamental clinical diagnostic criteria include:
- Onset of symptoms before 5 years of age.
- Duration of febrile episodes limited to less than 14 days.
The presence of these characteristics is crucial, as mutations in the MVK gene are less likely in their absence.
Evaluation of Immunoglobulin D (IgD) Levels
Elevated IgD levels are commonly observed in numerous patients, although this finding is not universal, particularly in children under 3 years old. These levels tend to rise both during a febrile episode and between them. It is essential to interpret this elevation cautiously, as IgD levels can also increase in other periodic fever syndromes, such as Familial Mediterranean Fever and TRAPS, as well as in other chronic inflammatory conditions. Malignancy. inflammatory.
Additional Useful Laboratory Tests
During an acute attack, analysis of organic acids in urine frequently reveals elevated levels of mevalonic acid.
Furthermore, during the course of a febrile episode, significant increases are observed in the white blood cell count (leukocytosis), the erythrocyte sedimentation rate (ESR oror leukocytosis), theESR or ESR), protein C-reactive protein. (CRP) and amyloid serum amyloid A (SAA). Serum IgA levels may also increase.
Tests employing radiometric assays can confirm reduced mevalonate kinase activity, either in white blood cells or in cells.
A biopsy Skin biopsy Avoidance Strategies for Triggering Factors could reveal a mild vasculitis.
Confirmation by DNA Analysis
The definitive diagnosis of HIDS is confirmed by DNA analysis demonstrating the presence of two pathogenic mutations associated with the disease in the MVK gene. In most cases, the individual presents two different mutated alleles, a condition known as compound heterozygosity heterozygosity.
Treatment Options for HIDS
A wide range of treatments have been investigated for HIDS, but none have demonstrated universal or consistent efficacy:
- Colchicine: Generally ineffective, although isolated cases of success have been reported.
- Immunosuppressive drugs Insect stings, such as bees or wasps. non-steroidal anti-inflammatory drugs (NSAIDs)NSAIDs).
- Nonsteroidal anti-inflammatory drugs (NSAIDs). inhibit Statins (e.g., simvastatin): Act by inhibiting HMGCoA-reductase, decreasing mevalonic acid synthesis.
- Corticosteroids steroidsSystemic Corticosteroids: A single dose at the onset of an attack can mitigate its severity and duration (recommended administration of 1 mg/kg).
- The selection of the most appropriate treatment should be determined by a healthcare professional, considering the intensity of the symptoms and the patient's general health.
- Cyclosporine.
- Mycophenolate.
- Immunoglobulin Dapsone.
- Cyclosporine. receptor Thalidomide. tyrosine Intravenous Immunoglobulin (IVIG). necrosis tumorBiologic agents: Include anakinra (an interleukin-1 receptor antagonist) and etanercept (a tumor necrosis factor alpha inhibitor). It has been documented that these reduce the frequency and/or severity of attacks by up to 80%. However, there are also reports where these treatments have caused an increase or prolongation of episodes.
Mevalonic Aciduria (MIM 610377)
Mevalonic aciduria shares the affected gene and the same enzyme as HIDS; however, the resulting enzyme deficiency is almost total or complete. This condition is also called mevalonate kinase deficiency. The genetic mutations identified to date are usually located diseases at one end of the enzyme structure. Mevalonic aciduria produces significant neurological neurological effects, derived mainly from the inadequate production of cholesterol, an essential component for the brain and development of the nerves.
nerve development. Patients with mevalonic aciduria experience the same febrile episodes as in HIDS, but additionally develop profound developmental, dystrophy delay, cataracts. retinal dystrophy (with associated visual defects) and joint cataracts progressive . They also present with mild anemia. facial deformities and hepatomegaly/splenomegaly (enlargement of the liver and spleen). Less severely affected individuals may exhibit mild intellectual disability, growth arrest, progressive cerebellar ataxia uveitis. (unsteadiness when walking) and anemia . Ocular complications arise during childhood and adolescence, including cataracts and uveitis. Likewise,.
myopathy.
(muscle weakness) may develop. In severe cases, mevalonic aciduria is fatal during the first decade of life. genetic, Elevated levels of mevalonic acid are consistently detected in urine samples at all times. prenatal.
