Inheritance:
Autosomal dominant with variable penetrance
Prevalence:
In the U.S.: 1-5 in 100,000 population; gene frequency
estimated at 1-2 in 10,000
Internationally: can be as high as 1 in 1,000 in Northern
Sweden
Affects women more than men, 1.5-2.1:1
Locus:
PBGD gene at 11q23.3 (porphobilinogen deaminase)
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Natural History:
Symptoms generally present between 18 — 40 years
of age. The sequence is typically abdominal pain followed
by psychiatric involvement and peripheral neuropathies.
Most individuals are asymptomatic between episodes.
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Defining Characteristics:
Respiratory
Respiratory paralysis
Gastrointestinal
Motor: Muscle weakness, acute ataxia, bulbar paralysis,
cranial nerve
palsies, decreased deep tendon reflexes
Sensory: sensory loss, pain in the head, neck, chest,
limbs, parasthenia
Autonomic: tachycardia, hypertension, fever
Seizures
Other
Increased incidence of hepatocellular carcinoma
Increased delta-aminolevulinic acid (ALA) and porphobilinogen
(PBG) during
acute attacks
Occasional port wine color in urine
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Psychiatric Characteristics:
May be present in 25-80% of cases of AIP; include anxiety,
depression, schizophrenia symptoms (hallucinations, social
withdrawal, delusions, catatonia, disruptive behavior),
hysteria, insomnia, restlessness, violence, delirium.
Common presentation includes brief psychiatric episodes,
often indistinguishable from schizophrenia or bipolar
disorder, associated with gastric pain; recovery is usually
complete.
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References:
Crimlisk, H.L. The little imitator-porphyria: a neuropsychiatric
disorder. Journal of Neurology, Neurosurgery and Psychiatry 62:
319-328 (1997).
Santosh, P.J., Malhotra, S. Varied psychiatric manifestations
of acute intermittent porphyria. Biol Psychiatry 36:
744-747 (1994).
Tishler, P.V., et al. High prevalence of intermittent
acute porphyria in a psychiatric patient population. Am
J Psychiatry 142: 1430-1436 (1985).
eMedicine
http://www.emedicine.com/MED/topic1880.htm
PEDBASE
http://www.icondata.com/health/pedbase/files/ACUTEINT.HTM
OMIM
http://www.ncbi.nlm.nih.gov/htbin-post/Omim/dispmim?176000.cs
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Velocardiofacial
Disorder