Br J Dermatol 2018 Nov 16;179(5):1135-1140. Epub 2018 Sep 16.
Cambridge Institute for Medical Research, University of Cambridge, Cambridge, U.K.
Background: Midface toddler excoriation syndrome (MiTES) is a condition recently reported in three unrelated children. Habitual scratching from the first year of life inflicted deep, chronic, scarring wounds around the nose and eyes. One child had a mild neurological deficit but there was no other evidence of insensitivity to pain. Bilateral distribution and localization to the midface distinguish MiTES from other causes of self-inflicted skin damage such as trigeminal trophic syndrome. An earlier study of five siblings from a consanguineous Irish family, with lesions corresponding to MiTES plus other sensory deficits, showed homozygous mutations in a gene for hereditary sensory and autonomic neuropathy type VIII (HSAN8), PRDM12.
Objectives: To study further cases of MiTES, including analysis of PRDM12.
Methods: We describe five further children, from four families, with facial lesions typical of MiTES, in whom mutation analysis of PRDM12 was carried out.
Results: Homozygous or compound heterozygous pathogenic expansions of the PRDM12 polyalanine tract were found in four of five affected individuals, in three families.
Conclusions: Our finding of autosomal recessive mutations in PRDM12 in four of five patients with MiTES extends the phenotypic spectrum of PRDM12 mutations, which usually cause HSAN8, characterized by mutilating self-inflicted wounds of the extremities, lips and tongue. By contrast, MiTES shows severe midfacial lesions with little if any evidence of generalized pain insensitivity. The condition is probably genetically heterogeneous, and other congenital insensitivity to pain and HSAN genes such as SCN11A may be implicated. This new understanding of the nature of MiTES, which can masquerade as factitious disease, will facilitate appropriate management.