- tachycardia (rapid HEART RATE)
- URINARY RETENTIONand URINARY INCONTINENCE
The diagnostic path includes blood and urine
tests to measure the presence of key porphyric
enzymes. In people who know they have por-
phyria, exposure to identified precipitating factors
—which include numerous drugs, hormones, and
nutrients—will bring on an attack. HYPERTENSION
(high BLOOD PRESSURE) can develop during an
attack and persist after symptoms subside.
Treatment Options and Outlook
Severe symptoms, particularly neurologic, require
hospitalization and aggressive treatment that may
include intravenous heme administration (the
only form in which heme is available). Medica-
tions safe to take to relieve and control symptoms
include narcotic pain relievers and phenothiazines
to relieve nausea and vomiting or neuropsychi-
atric symptoms. It is crucial to stop any substances
that may have precipitated the attack. Most symp-
toms subside within two to three weeks, and most
people fully recover within six weeks. Some peo-
ple experience extended muscle weakness.
Attacks may occur without provocation. Many
people who have porphyria seldom experience
attacks, however.
Risk Factors and Preventive Measures
The porphyrias are inherited genetic disorders.
The risk of porphyria depends on the inheritance
pattern. There are no measures to prevent por-
phyria. People who have porphyria, or who have
family members who have porphyria, might con-
sider GENETIC TESTINGand GENETIC COUNSELING. It is
possible to be a CARRIERfor the autosomal reces-
sive forms of porphyria.
See also BULLA; CYTOCHROME P 450 (CYP 450 )
ENZYMES; GENE; HALLUCINATION; HORMONE; MUTATION;
RASH.progeria A very rare genetic disorder, commonly
called severe premature aging, that arises from a
MUTATIONin a single GENEon CHROMOSOME1 called
lamin A (LMNA). The gene encodes a protein, also
called lamin A, that is important for proper func-
tioning of the membrane of the cell nucleus. In
progeria this protein is abnormal, resulting in
rapid deterioration of the nuclear membrane and
destruction of the cell. The diagnostic path is pri-
marily clinical, based on symptoms. Most children
who have progeria die of cardiovascular problems
such as HEART ATTACKorSTROKEby the age of 12 or
13 years. As a consequence of research into the
causes of progeria, scientists have discovered other
mutations of the same gene that cause uncommon138 Genetics and Molecular Medicine
THE PORPHYRIASPorphyria Deficient Enzyme Inheritance Pattern
acute intermittent porphyria (AIP) porphobilinogen deaminase (PBG-D) autosomal dominant
ALAD-deficiency porphyria (ADP) aminolevulinic acid dehydratase (ALAD) autosomal recessive
congenital erythropoietic porphyria (CEP) uroporphyrinogen III cosynthase autosomal recessive
erythropoietic protoporphyria (EPP) ferrochelatase autosomal dominant
hepatoerythropoietic porphyria (HEP) uroporphyrinogen decarboxylase autosomal recessive
hereditary coproporphyria (HCP) coproporphyrinogen oxidase autosomal dominant
porphyria cutanea tarda (PCT) uroporphyrinogen decarboxylase autosomal dominant
variegate porphyria (VP) protoporphyrinogen oxidase autosomal dominant