Porphyria, Acute Intermittent

Alternative Names

  • AIP
  • Porphyria, Swedish Type
  • Porphobilinogen Deaminase Deficiency
  • PBGD Deficiency
  • Uroporphyrinogen Synthase Deficiency
  • UPS Deficiency
  • Porphyria, Acute Intermittent, Nonerythroid Variant
  • Porphyria, Chester Type
  • PORC
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WHO-ICD-10 version:2010

Endocrine, nutritional and metabolic diseases

Metabolic disorders

OMIM Number

176000

Mode of Inheritance

Autosomal dominant

Gene Map Locus

11q23.3

Description

Acute intermittent porphyria (AIP) is a rare, severe, and debilitating form of porphyria characterized by abnormalities in the production of heme - the iron containing part of hemoglobin. Major symptoms of AIP include nausea, constipation, urinary retention, incontinence, and dysuria, along with peripheral neuropathy involving wrist and foot drops and areflexia. Psychiatric complications like hysteria, anxiety, depression and/or phobias may also be encountered. Unlike most other porphyrias, AIP does not show cutaneous photosensitivity. Most patients however, remain asymptomatic.

Although primarily a genetic defect, AIP can be precipitated by environmental factors, including drugs like barbiturates, sulfonamides etc., reduced caloric intake, stress, and/or cyclic hormone fluctuations. The latter factor is commonly exhibited in women who experience AIP attacks according to their menstrual cycles.

Acute porphyrias can be diagnosed based on the presence of increased levels of delta-aminolevulinic acid (ALA) and porphoiblinogen (PBG). AIP can be confirmed if this increase is accompanied by a deficiency of the enzyme porphobilinogen deaminase (PBGD) in RBCs, although in some cases, PGBD may be normal in RBCs and deficient only in the liver. Genetic tests are also available on the HBMS gene for diagnosis. Treatment involves immediate cessation of any drug precipitating the attack, and administration of dextrose and hemin. In women with cyclic attacks of AIP, long-acting agonistic GnRH analogues may help.

AIP is transmitted in an autosomal dominant manner, and is caused due to defects in the HMBS (hydroxymethylbilane synthase) gene. This gene is responsible for an important step in the production of heme, that of assembling four molecules of porphobilinogen to form hydroxymethylbilane.

Molecular Genetics

AIP is transmitted in an autosomal dominant manner, and is caused due to defects in the HMBS (hydroxymethylbilane synthase) gene. This gene is responsible for an important step in the production of heme, that of assembling four molecules of porphobilinogen to form hydroxymethylbilane. Defects or mutations in this gene therefore, lead to reduced production of heme, as well as concomitant increase in the level of porphobilinogen. Total loss of function of the enzyme is incompatible with life.

Epidemiology in the Arab World

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Other Reports

Bahrain

Al-Jishi and Sreekantaswamy (2004) reported the first three patients with severe neurological manifestations secondary to AIP in Bahrain. The first case was of a 16-year old male who presented with weakness of upper and lower limbs of a week's duration, and had earlier been admitted twice for "acute abdomen". The patient was receiving antipsychotic medication for paranoid schizophrenia and the drugs could have precipitated the symptoms. Upon examination, he was found to have bilateral lower motor facial weakness, bilateral vocal cord paralysis, hypotonia in all limbs, absence of deep tendon reflexes, urine positive for porphiobilinogen, and reduced nerve conduction velocities. The patient showed significant recovery following treatment with Hematin for three days and tracheostomy. However, he developed tracheal stenosis at the site of tracheostomy and died due to respiratory failure. The second case was that of a 17-year old male presenting with recurrent vomiting and slurred speech, mild tachycardia, bilateral deafness, signs of sensorimotor peripheral neuropathy, and unsatisfactory respiration requiring mechanical ventilation. This patient had a family history of a similar case, with a brother who had died previously of similar symptoms. Assay showed urine positive for porphobilinogen, and erythrocyte PGB diaminase positive for coproporphyrin. Hematin was not available for treatment and the patient died following cardiac stand-still. The third patient was a 50-year old man, who was first admitted for recurrent vomiting, giddiness, and mild fever. He was found to have severe dysarthria, bilateral sixth nerve palsies, and poor gag reflexes. At that time, his urine was negative for porphobilinogen. He was treated with high doses of glucose, which completely alleviated his symptoms. After three years, he was re-admitted with similar symptoms after taking Diclofenec for backache. This time, however, the urine examination was positive for porphobilinogen and stool was positive for coproporphyrins. Hematin was unavailable and although he was treated with high doses of dextrose, the patient died due to acute respiratory failure. Family members of patient one and three were screened for porphyria, with negative results.

[Al-Jishi AA, Sreekantaswamy. Fatal neurological manifestations of Acute Intermittent Porphyria. Bahrain Med Bull. 2004; 26(2):67-9.]

Kuwait

Pinto et al. (2001) reported an 11 year old girl suffering from acute intermittent porphyria (AIP) at Al-Adan Hospital. The subject was born to healthy unrelated parents with four healthy children; she weighed 2.6kg at birth and experienced recurrent abdominal pain, seizures, behavioral changes, and passed purple-red urine confirming AIP diagnosis. In addition, the patient suffered from the syndrome of inappropriate antidiuretic hormone release (SIADH) due to hypothalamic dysfunction which resulted from persistent hyponatremia and non-specific modifications in the liver function. [Pinto R, Al-Naki H, Habeeb Y. A 11-year-old girl with acute intermittent porphyria (AIP). Kuwait Med J. 2001, 33(1): 68-70.]

Periasamy et al. (2002) reported a 15-year-old girl who presented with upper respiratory tract infection, fever, seizures, and abdominal pain. An initial diagnosis of encephalitis was made. She received antiviral drugs and anticonvulsants. Two weeks later, she developed progressive flaccid quadriplegia and facial weakness. She also developed respiratory paralysis and was intubated. Cytoalbuminous dissociation was seen in the cerebrospinal fluid. A diagnosis of severe Guillain-Barre syndrome was made. The patient received a course of intravenous immunoglobulins which did not result in any clinical improvement. Plasmapheresis, started after 12 weeks, led to partial improvement. The patient continued to have attacks of seizures, abdominal pain and vomiting with severe quadriparesis. A repeat screening test for urine porphyrins was positive, and AIP was confirmed by specific porphobilinogen deaminase in the blood. The patient was treated with large doses of intravenous glucose, followed by injections of hematin. The patient improved remarkably. She was extubated, discharged from Intensive Care Unit and started on a rehabilitation program.

Morocco

Aquaron et al. (1996) described three patients from Moroccan kindreds with acute intermittent porphyria (AIP). The propositus of family A originating from Mrirt, Morocco, is living in Embrun, France. This 26 year-old woman who experienced an acute attack with visceral manifestations presented an elevated urinary level of 5-ALA and PBG, and a half-normal activity in porphobilinogen deaminase (PBG-D) in red blood cells (RBC). The family's survey was carried out by measuring the PBG-D activity in RBC (normal values = 125 +/- 40 U). Three of the 16 subjects tested, beside the propositus, were found to be asymptomatic carriers (PBG-D < 70 U). The two patients of family B, originating from Tetouan in the Rif area, were living in Bastia, Corsica. The two brothers, respectively 37 and 39 years old, had a long history (6 years) of neuropsychiatric manifestations before the AIP diagnosis was evidenced by elevated urinary level of 5-ALA and PBG, and showed a partial deficiency, approximately, 50%, of PBG-D activity in RBC. The youngest patient also presented a peripheral neuropathy and recently died after surgery from an unknown reason at the age of 45.

Oman

Gilani and Alfour (1996) reported a case of acute intermittent porphyria (AIP) in a 24-year-old female, who presented with recurrent attacks of abdominal pain, vomiting, constipation, proximal muscle pain, and palpitation along with high blood pressure and sinus tachycardia over a period of seven years. Clinically, she was in pain, tachycardic (200/min) and with a blood pressure of 190/120 mmHg. Her systemic examination was normal apart from a distended tender abdomen. Routine urine and blood investigations were normal except for elevated urea of 94mg/dl. She was managed initially as a case of pheochromocytoma and received prazocin 0.5mg od (for one day) and propanolol 20mg tds along with pethidine for the pain. The diagnosis of AIP was suspected as her urine turned red on standing, and confirmed by detecting porphobilinogen in her fresh urine. She responded to the treatment which was supported with a high carbohydrate diet (300grams glucose/day), but developed hyponatremia which was controlled by fluid restriction and hypertonic saline. On discharge, she was asymptomatic and was prescribed propanolol 10mg tds.

[Gilani SN, Alfour NS. Acute Intermittent Porphyria. Oman Med J. 1996; 12(3):49-50.]

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