X-linked Ichthyosis
Other names: steroid sulfatase deficiency; recessive X-linked ichthyosis
OMIM: 308100
Inheritance: X-linked recessive
Incidence: 1:2,000 - 1:9,500
Key findings:
- skin: small, dark, firmly adherent scales; accentuated on sides of neck and trunk; generally spares face, palms, soles, antecubital and popliteal flexures
Associated findings:
- eyes: asymptomatic, white spots in cornea (50%)
- genitals: undescended testis (20%)
- nervous system: mental retardation or other neurologic abnormalities (rare)
- obstetric: prolonged labor in mothers of affected sons (usual)
Age at first appearance: may be present at birth; often not noticed for months or years
Long-term course: overall severity does not change with time; distinctly worse in dry weather
Diagnostic tests: cholesterol sulfate level in blood; chemical or fluorescence analysis of cellular DNA
Abnormal gene: steroid sulfatase
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