Genomic coordinate 9:113,386,312
Here I present: “Acute Hepatic Porphyria”, Victor McKusick, Mendelian Inheritance in Man’, 1966. 急性肝臟卟啉症。 icd10=E80.21
INTRODUCTION.
Acute Hepatic Porphyria (AHP) is a group of inherited disorders of hepatic heme biosynthesis characterized by acute neurovisceral attacks due to accumulation of ALA (δ-aminolevulinic acid) and PBG (porphobilinogen).
Types of Acute Hepatic Porphyria.
1. Acute Intermittent Porphyria (AIP) – most common.
2. Hereditary Coproporphyria (HCP)
3. Variegate Porphyria (VP)
4. ALA-dehydratase Deficiency Porphyria (ALADP).
All acute hepatic porphyria are autosomal dominant except ALADP (autosomal recessive).
Pathophysiology.
Defects in enzymes of the hepatic heme pathway → ↓ heme → ↑ ALAS1 (rate-limiting enzyme)
Accumulation of ALA & PBG → neurotoxicity
Triggers precipitate attacks by inducing ALAS1.
Common Triggers.
Drugs (barbiturates, sulfonamides, antiepileptics, rifampin)
Hormonal changes (luteal phase, oral contraceptives)
Fasting/dieting, low-carb states
Alcohol, smoking
Infection, stress
Pregnancy
Clinical Presentation.
Attacks are acute, severe, and systemic.
1. Abdominal Symptoms.
Severe diffuse abdominal pain (neuropathic, no peritonitis)
Nausea, vomiting, constipation
2. Neurologic Features.
Peripheral neuropathy (motor > sensory)
Weakness → quadriparesis
Seizures (due to hyponatremia or neurotoxicity)
Autonomic dysfunction (tachycardia, hypertension)
3. Psychiatric Symptoms.
Anxiety, agitation, confusion, hallucinations’.
4. Urinary Findings.
Reddish / port-wine urine (oxidized PBG).
There is evidence acute hepatic porphyria Doss-type is caused by mutation in the gene encoding delta-aminolevulinate dehydratase (ALAD) gene encoded on cytogenetic location 9q32 and genomic coordinate 9:113,386,312 .
