Fabry's Disease
Subjective
A 67-year-old white female presented for a routine eye examination
with typical visual complaints of occasional blur at distance
and near. Her current eyeglasses are four years old. She
has experienced mild photophobia in bright light and while
driving at night. The patient is taking ranitidine hydrochloride
(Zantac) and loratadine (Claritin D) and is allergic to ibuprofen
(Motrin). There is no known personal or family history of
ocular disease, surgery or injury.
Objective:
- Visual acuity: (20/25) OU
- Pupils: equal, round and reative OU
- Lids: uninvolved OU
- Conjunctiva: slight injection OU
- Cornea: both corneas demonstrated a pronounced browish-tan
verticillate pattern within the sub-epithelial tissues (Fig.1).
There was no disruption of precorneal tear film as demonstrated
with flurescein dye
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Fig. 1 This symptomatic female carrior of Fabry's
disease shows the classic whorl-like deposits in the
basal layer of the corneal epithelium.
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- Lens: Grade I nuclear sclerotic cataracts OU
- Tension by applanation: 17/17 mm Hg at 9:30am
- Dilated fundus exam: 0.2 cup-t0-disc OU with maculae clear;
slight tortuosity to the retinal blood vasculature OU
Assessment:
Plan:
- No medical intervention is warranted in this healthy female
carrier
Comments:
A retrospective history revealed that this patient has had
three brothers who all died in their 50s from heart and/or
kidney disease. Since Fabry's is an X-linked recessive disease,
males are afflicted, and females are carriers. Genetic counseling
should be considered for family members of child-bearing
age. In male patients with Fabry's disease, the main sympton
is intermittent attacks of pain in the toes, fingers, palms
or soles. There is often associated fever and increased sedimentation
rate. Cardiovascular and renal complications reduce the life
expentancy in males to 40-50 years.
Optometric physicians may be in a primary position to diagnose
Fabry's disease. The corneal deposits are seen in males and
heterozygous females when other manifestations of the disease
are in their early stages. Along with the corneal opacities,
posterior spoke-like cataracts are said to be pathognomonic
for Fabry's disease. Conjunctival and retinal vessel changes
are more nonspecific, yet suggestive of the disease. Keep in
mind that all of these ocular findings may not be present with
every patient.
General Observations:
- The following asymptomatic, superficial corneal findings are
found in Fabry's disease:
- Diffuse whorl-like deposits (cornea verticillate) are seen
in the epithelium (basal layers); in more advanced cases, the
deposits radiate from a point below the center of the cornea
or as whorled streaks extending to the periphery (Fig. 2).
This multi-system, X-linked recessive disease first repoted
in dermatological literature in 1898.
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Fig. 2 A 30-year-old male patient has the distinctive
corneal verticillate (whorled streaks) extending
to the periphery.
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- Corneal deposits similar to the classic amiodarone, chloroquine,
chlorpromazine, or indomethacin, are seen in both males and
females.
- Visual acuity is generally not affected.
- Fabry's disease is a potentially fatal lyposomal storage disorder
which results from deficient activity of alpha-galactosidase
A. This multi-system, X-linked recessive disease was first
reported in the dermatological literature in 1898.
- In affected males, Fabry's disease usually causes premature
death (age 40-50) from kidney, cardiovascular, or other systemic
complications.
- A deficiency of the enzyme alpha-galactosidase A causes a build-up
of ceramide trihexoside in the kidney and heart vasculature.
- The female carrier is either asymptomatic or has mild systemic
symptomatology. It is in these relatively healthy patients
that such keratopathy is likey to be discovered in out-patient
clinical settings.
- Ocular findings:
- Corneal opacities (90% of cases)
- Spoke-like cataracts (50%)
Up until about 2003, there was no known therapy for
Fabry's patients. Since this disease is characterized
by a genetically programmed enzyme deficiency, it
stands to reason that if we could find a medicine
to function as a surrogate for this enzyme, the process
of intravascular lipid accumulation (i.e. ceramide
trihexoside) could be slowed, halted, or reversed.
A galsidase beta (Fabrazyme) has been developed,
and seems to be a highly effective therapeutic intervention.
It is administered IV every two weeks for the life
of these affected patients.
We urge you to peruse the following websites for additional
information:
www.fabryregistry.com and www.fabrycommunity.com
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