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A form of spinocerebellar ataxia
associated with chorioretinal dystrophy and hypogonadotropic hypogonadism.
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Unknown. Only 19 cases from 10 families
have been reported in the literature. The syndrome remains poorly recognized
and probably underreported.
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Pleiotropic single-gene disorder with an
autosomal recessive pattern of inheritance.
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The tissues involved are all of neuroectodermal
origin; however, the exact link between the three features is unclear. The
nature of the gene involved and its specific role in the pathophysiology are
unknown. The absence of a response to luteinizing hormone also suggests disturbed
pituitary function. The abnormal pattern of the thyroid-stimulating hormone and
prolactin response to thyrotropin-releasing hormone plus the growth hormone
response to gonadotropin-releasing factor and insulin-induced hypoglycemia
also point to a hypothalamic involvement.
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Clinical findings consistent with the syndrome. No
specific diagnostic tests are available. CT and/or MRI scans show evidence
of cerebellar atrophy. Serum levels of luteinizing hormone,
follicle-stimulating hormone, estrogen, and testosterone are abnormally low.
Electroretinography is abnormal, with a marked reduction in the amplitude of
both rods and cones. Fluorescein angiography demonstrates filling of the
major choroidal vessels in the atrophic regions combined with an extensive
loss in the choriocapillaris.
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Characterized by hypogonadotropic hypogonadism.
Usually this disorder is diagnosed at the onset of puberty (primary amenorrhea, poor
development of sexual organs, sparse growth of secondary hair, short
stature, delayed puberty, delayed bone age, infertility), spinocerebellar
ataxia (with a variable age of onset; impaired balance, ataxic gait, mild
dysmetria on finger-to-nose testing, but marked dysmetria on heel-to-shin
testing, nystagmus, bilateral extensor plantar responses), and choroidal
dystrophy (variable age of onset, diffuse and slowly progressive, with
involvement of the choriocapillaris, retinal pigment epithelium, and outer
retina, resulting in loss of visual acuity with a dense ring scotoma and a
spared central field). Muscle strength, sensibility, and proprioception are
normal.
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Clinical history and examination to
evaluate the progression of the condition.
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No specific anesthetic considerations.
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Patients are often on sex hormone
replacement therapy (testosterone, estrogen, oral contraceptives). Depending
on the procedure, deep vein thrombosis prophylaxis is recommended because of
estrogen replacement therapy. No other specific pharmacological
considerations.
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Gordon-Holmes Syndrome: Genetic disorder with hypogonadism and
progressive cerebellar ataxia.
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Kallmann Syndrome: Inherited syndrome characterized by
hypogonadotropic hypogonadism and anosmia caused by agenesis of the
olfactory bulbs, often combined with other birth defects (cardiac anomalies,
cleft lip/palate, renal anomalies).
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Other forms of spinocerebellar ataxia, such as the following:
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Machado-Joseph Disease: Form of autosomal dominant inherited
spinocerebellar ataxia with clinical onset usually in adulthood but
occasionally in adolescence.
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Infantile-Onset Spinocerebellar Ataxia (IOSCA): Some researchers
also used the term spinocerebellar ataxia (SCA) type 8 for this disease, but the term has not been
uniformly accepted. IOSCA is an inherited spinocerebellar ataxia with onset
usually in the first 2 years of life.
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