Introduction
- Definition: Rare X-linked genetic disorder affecting the skin, hair, teeth, nails, eyes, and CNS.
- Prevalence:
- Reported prevalence: ~1.2/100,000 in Europe.
- Female:Male ratio: 20:1.
- High penetrance with variable expressivity.
Clinical Characteristics
-
Skin Lesions:
- Follow Blaschko lines (cell migration pathways during embryogenesis).
- Evolve through four stages:
- Stage I (Bullous):
- Blister-like eruptions (linear on extremities, circumferential on the trunk).
- Onset: Birth to ~8 weeks; resolves by ~18 months.
- Stage II (Verrucous):
- Wart-like rash, linear or circumferential.
- Onset: Resolves stage I; lasts months to years.
- May include dystrophic nails and delayed tooth eruption.
- Stage III (Hyperpigmentation):
- Slate gray/brown swirled patterns.
- Onset: ~6 months; persists into adulthood, fades in late teens/20s.
- Stage IV (Atretic):
- Linear hypopigmentation, alopecia (scalp, trunk, extremities).
- Follows fading hyperpigmentation; not present in all individuals.
Genetics
- Alopecia (patchy or generalized).
- Sparse, wiry, or lusterless hair.
- Sparse eyelashes or eyebrows.
Diagnosis
- Stage I (Bullous):