Introduction
Ectodermal dysplasia (ED) is a rare heterogenous group of heritable disorder that manifests as developmental defects of two or more tissues of ectodermal origin.(1) The skin, hair, nails, eccrine glands, and teeth are the tissues primarily affected(2). Other tissues of ectodermal origin that may be involved are mammary gland, central nervous system, external ear, cornea, conjunctiva, melanocytes, and lacrimal gland and duct(3)(4). All patterns of inheritance like autosomal recessive/dominant, X-linked and mitochondrial have been described. The ED which is congenital, diffuse and nonprogressive, has an estimated incidence of around seven cases per 100,000 live births(1). Traditionally ectodermal dysplasia is classified into two types based on sweat gland function. The first one is X-linked hypohidrotic type (Christ-Siemens-Touraine syndrome) presenting with a classical triad of hypodontia, hypohidrosis (reduced or absent sweating), and hypotrichosis. In contrast to that, the second one is the hydrotic type (Clouston syndrome) characterized by normal sweat gland function with other ectodermal defects and is inherited in autosomal dominant manner(1). But this simple classification has failed to address the anomalies associated with nail, hair and teeth in various forms of ED.