Use of gonadotropin-releasing hormone analog with tibolone to prevent cyclic attacks of acute intermittent porphyria

Acute intermittent porphyria: a disease with low penetrance and high heterogeneity

Acute intermittent porphyria (AIP) is caused by mutations in the gene encoding hydroxymethylbilane synthase (HMBS), a key enzyme in the heme biosynthesis pathway. AIP is an autosomal dominant disorder characterized by low penetrance and a highly heterogenous clinical presentation. The estimated prevalence of AIP is 5-10 cases per 100,000 persons, with acute attacks manifesting in less than 1% of the at-risk population. This low frequency of attacks suggests significant roles for oligogenic inheritance and environmental factors in the pathogenesis of the disease. In recent years, identification of several modifier genes has advanced our understanding of the factors influencing AIP penetrance and disease severity. This review summarizes these factors including the impact of specific HMBS mutations, oligogenic inheritance, mitochondrial DNA copy number, age, sex, the influence of sex hormones, and the role of environmental factors. Further studies into the etiology of AIP disease penetrance should inform pathogenesis, potentially allowing for the development of more precise diagnostic and therapeutic approaches.

Acute intermittent porphyria symptoms during the menstrual cycle

BACKGROUND

Acute intermittent porphyria (AIP), a life-threatening form of the disease, is accompanied by several pain, mental and physical symptoms.

AIMS

In this study, we evaluated the cyclicity of AIP and premenstrual syndrome (PMS) symptoms in 32 women with DNA-diagnosed AIP during their menstrual cycles, in northern Sweden.

METHODS

The cyclicity of AIP symptoms and differences in them between the follicular and luteal phases, and the cyclicity of each symptom in each individual woman in different phases of her menstrual cycle were analysed with a prospective daily rating questionnaire. PMS symptoms were also evaluated in the patients on a daily rating scale.

RESULTS

Of the 32 women, 30 showed significant cyclicity in at least one AIP or PMS symptom (P < 0.05-0.001). Back pain (10/32) was the most frequent AIP pain symptom and sweet craving (10/15) was the most frequent PMS symptom. Pelvic pain (F = 4.823, P = 0.036), irritability (F = 7.399, P = 0.011), cheerfulness (F = 5.563, P = 0.025), sexual desire (F = 8.298, P = 0.007), friendliness (F = 6.157, P = 0.019), breast tenderness (F = 21.888, P = 0.000) and abdominal swelling (F = 16.982, P = 0.000) showed significant cyclicity. Pelvic pain and abdominal swelling (rs = 0.337, P < 0.001) showed the strongest correlation. The age of women with latent AIP was strongly correlated with abdominal swelling during the luteal phase (rs = 0.493, P < 0.01).

CONCLUSION

Our results suggest that the symptoms of AIP patients change during their menstrual cycles.

Treatment options in acute porphyria, porphyria cutanea tarda, and erythropoietic protoporphyria

The porphyrias are a group of uncommon metabolic diseases caused by enzyme deficiencies within heme biosynthesis that lead to neurotoxic or phototoxic heme precursor accumulation. There are four acute porphyrias characterized by neuropsychiatric symptoms: acute intermittent porphyria, variegate porphyria, hereditary coproporphyria, and 5-aminolevulinic acid dehydratase deficiency porphyria. Treatment includes elimination of any porphyrogenic factor and symptomatic treatment. Carbohydrate and intravenous heme administration constitute specific therapies in the disorders' acute phase. The mainstay treatment in the cutaneous porphyrias is avoidance of sunlight exposure. In porphyria cutanea tarda and the two acute porphyrias with skin manifestations, variegate porphyria and hereditary coproporphyria, care of the vulnerable skin is important. In porphyria cutanea tarda, specific treatment is accomplished by a series of phlebotomies and/or by low-dose chloroquine administration. In erythropoietic protoporphyria, light-protective beta-carotene is prescribed.