Genetic conditions are increasingly recognised as a cause of multisystem 
diseases in children. We report a 6-year-old boy with hypohidrotic ectodermal 
dysplasia, immunodeficiency, osteopetrosis and lymphoedema, associated with a 
novel mutation in the NF-κβ essential modulator (NEMO) gene. He is the longest 
surviving of three reported boys with these clinical features. Hypohidrotic 
ectodermal dysplasia, a congenital disorder of teeth, hair and eccrine sweat 
glands is most commonly inherited as an X-linked recessive trait. Associated 
immunodeficiency (HED-ID) may give rise to serious infections in early life. 
Mutations in the NEMO gene give rise to a heterogeneous group of disorders, 
including the X-linked dominant disorder incontinentia pigmenti. This is 
characterised by typical skin changes leading to linear pigmentary change and 
variable associated features; in males, prenatal death usually occurs. Our 
patient, like one if the previous cases and all of their mothers, demonstrates 
features of incontinentia pigmenti.