A 5-day-old term female newborn has linear clusters of vesicles on an inflamed base distributed along Blaschko lines over the limbs and trunk. Peripheral smear of vesicle fluid shows abundant eosinophils. Over subsequent months the lesions crust, then leave whorled hyperpigmentation. Her family history is notable only for a maternal grandmother with similar childhood skin findings and two unexplained male fetal losses. What inheritance pattern explains this presentation?
- A X-linked dominant, lethal in males in utero ✓
- B X-linked recessive
- C Autosomal recessive
- D Mitochondrial maternal transmission
Correct answer: A. X-linked dominant, lethal in males in utero
Explanation
The four-stage evolution of vesicular, verrucous, hyperpigmented whorls, and finally hypopigmented streaks along Blaschko lines is diagnostic of incontinentia pigmenti (Bloch-Sulzberger disease), caused by mutations in the IKBKG gene. It is X-linked dominant and is lethal in utero in affected males, explaining the recurrent male fetal losses in the pedigree; surviving affected children are almost always female. Eosinophilia in the vesicle fluid supports the diagnosis over neonatal herpes.
Reference: Hurwitz Clinical Pediatric Dermatology, 5th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.