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Rare inherited disorder characterized by silvery hair,
pigment abnormalities of the skin, and early-onset central nervous system
dysfunction.
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Melanolysosomal Neurocutaneous Syndrome. (Caveat: The name
Elejalde syndrome has also been used synonymously for
Acrocephalopolysyndactylous Dysplasia. To avoid confusion, we recommend
reserving this name for the syndrome described here.)
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Approximately 11 cases have been reported.
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Autosomal recessive. Candidate genes for
Elejalde syndrome have been sought in a variety of genes involved in
organellogenesis and intracellular trafficking. These genes are directly or
indirectly involved in pigmentation disorders throughout the expression of
adaptor-like protein complex(AP)-3 factor, which is involved in the budding
of coated vesicles from the Golgi system.
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Abnormal melanocytes, melanosomes, and inclusion
bodies in fibroblasts may be present. There are speculations that myosin V
protein may be affected and probably responsible for the severe generalized
hypotonia. The molecular basis of the disease remains to be elucidated.
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Light microscopy of the hair is characterized by the
presence of small and large melanin clumps irregularly distributed along the
hair shaft but predominantly in the medulla. Skin biopsy specimens may
reveal a normal number of melanocytes but irregular distribution and
irregular size of melanin granules in the basal layer. Electron microscopy
of the skin reveals melanocytes with melanosomes of various sizes and at
various developmental stages. Because of a maturation defect, melanization
of the melanosomes is incomplete; however, in contrast to Griscelli and
Chediak-Higashi Syndrome (the two other “Silvery Hair Syndromes”),
both humoral and cellular immunity are normal.
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Scalp hair, eyelashes, and eyebrows are silver.
Sun exposure leads to pronounced and long-lasting skin tanning. The age at
onset of neurologic signs can range from 1 month to 11 years and include
severe muscular hypotonia, ataxia, seizures, hyperreflexia or hyporeflexia,
spastic or flaccid hemiplegia or quadriplegia, and ocular features (e.g.,
congenital amaurosis, nystagmus, diplopia, pupillary areflexia). Mental
retardation with delayed psychomotor development usually is obvious in the
first month of life. Magnetic resonance imaging can demonstrate cerebellar
hypoplasia/atrophy.
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No data regarding anesthetic
management or pharmacological implications in this disorder have been
published. Seizure control, assessment of muscular hypotonia, and the
potential presence of recurrent pulmonary aspirations are the main focus
points in the preoperative evaluation. A chest radiograph might be
indicated. Failure to thrive may be present secondary to poor feeding and
results in electrolyte and fluid imbalances. Blood work should include serum
levels of electrolytes. Depending on the type and extent of surgery,
prolonged postoperative mechanical ventilation may be required. Mental
retardation may limit patient cooperation. Sedative premedication and/or the
presence of the primary caregiver during induction of anesthesia may be
helpful.
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Recurrent aspiration is a described
complication in this syndrome. A rapid-sequence induction technique is
recommended. Severe hypotonia may require reduced amounts or no
neuromuscular blocking agents. Positioning may be difficult in the presence
of spastic paraplegia or tetraplegia.
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