ALA Dehydratase Deficiency Porphyria Clinical Presentation

Updated: Mar 25, 2021
  • Author: Smeeta Sinha, MD; Chief Editor: Emmanuel C Besa, MD  more...
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ALAD deficiency porphyria (ADP) is an acute hepatic porphyria that produces only neurovisceral signs and symptoms. Heterozygotes are asymptomatic.

The clinical manifestations mimic those seen in acute intermittent porphyria, as follows:

  • Abdominal pain is frequently reported; it is colicky in nature and may mimic a surgical abdomen

  • Nausea, vomiting, constipation, diarrhea, and urinary retention are possible

  • Neuropathy may be motor or sensory in nature; common symptoms include upper- and lower-extremity weakness and tingling

  • Respiratory impairment is possible

  • Seizures are possible

  • Psychosis may occur in severe attacks

Exacerbation of symptoms occurs with stress, decreased calorie intake, and alcohol consumption. Note:  This form of porphyria is not associated with cutaneous photosensitivity

The clinician should rule out the following:

  • Exposure to exogenous inhibitors of ALAD, including styrene, lead, trichloroethylene, and bromobenzene

  • Hereditary tyrosinemia, which leads to accumulation of succinylacetone, an ALAD inhibitor


Physical Examination

On physical examination, patients with ALAD deficiency porphyria (ADP) may show evidence of abdominal tenderness or neuropathy. [14]  Autonomic neuropathy, including tachycardia and systemic arterial hypertension, are common presenting signs during acute attacks. Bulbar and respiratory muscle paresis can occur. Muscle hypotonia of the arms and legs is noted in some patients.