INTRODUCTION Ectodermal derivatives include sweat glands, hair, nails, nerves, and detal enamel. Disturbance in any of these ectodermally derived tissues leads to the disorder known as hereditary ectodermal dysplasia (HED). Hypohidrotic ectodermal dysplaisa (HHED) being the most frequent subtype and the other less common is hydrotic ecto- dermal dysplasia (HyED). 1 Danz (1792) first encountered a case of HED. Freire-Maia and Pinheiro are credited with the first systematic classification of HED. 2 Mutations in ectodysplasin A and ectodysplasin A receptor are responsible for HED. Here, we report four cases of HHED from the same family of Indian descent. CASE REPORT Cases I and II: Two male siblings aged 18 and 16 years respectively reported to our clinic with the chief complaint of spacing between the teeth present in both upper and lower jaws. Common findings in Cases I and II: On clinical examination, they revealed missing teeth in all quadrants. Their parents were apparently normal, although the mother reported to have missing teeth in early life. According to parents, the siblings had sparse hair in their early childhood which increased over time. The eyebrows and eyelashes were scanty. The skin appeared glossy, smooth, thin, and hyper pigmented. The ear lobes were small and attached to the skin of the cheek. They also complained of inability to sweat. Case I had a hoarse voice which may be due to disturbance in pharyngeal and laryngeal developments. The nails were ill formed with some of them showing free lateral margins flushing with the skin and some of them were spoon shaped (Figure 1). Case II, in addition to the above mentioned common features, had flat nipples. This patient too showed spoon shaped nails. He also complained of recurrent ulcerations causing severe pain and discomfort. Case III: One of their 12-year female maternal cousins also had similar features of oligodontia in addition to hypotrichosis involving facial hair, eyebrows and eyelashes. Her first tooth had erupted at the age of 20 months. Radiograph showed many missing permanent tooth germs and also deciduous teeth that had not shed till this age. Anterior teeth were conical shaped (Figure 2). The parents also reported that their first male child had scanty hair in his childhood, but died after 2 years. The reason of his death was uncertain. Case IV: A 3-year female sibling also had missing teeth and sharp conical teeth. Examination revealed scanty and fine hair on the scalp. The bridge of the nose was depressed. The supraorbital ridges were pronounced with frontal bossing and protuberant lips. Intraoral examination revealed partial absence of teeth and high arched palate (Figure 3). This description was fitting the diagnosis of HHED. The patients were referred to dermatologist to confirm the findings and the diagnosis of HHED. The patients were treated for prosthetic rehabilitation and were asked to wear cool clothing. Journal of the College of Physicians and Surgeons Pakistan 2019, Vol. 29 (4): 381-383 381 CASE SERIES Hypohydrotic Ectodermal Dysplasia in an Indian Family Anish A. Gupta 1 , Swati S Gotmare 2 , Megha Jain 1 , Treville Pereira 2 and Pooja Khare 3 ABSTRACT Hereditary ectodermal dysplasia (HED) is a rare genetic disorder chiefly affecting ectodermally derived structures including hair, nails, sweat glands etc. with pathognomic manifestations such as hypotrichosis, hypohidrosis, and hypodontia. Hypohidrotic ectodermal dysplaisa, being the most frequently encountered subtype and HED, being the rare subtype. HED is primarily transmitted through X-linked recessive trait in which the gene is carried by the female and manifested in male. Although rare, this disorder may be seen affecting lot of members of the same family. We hereby report a series of four cases with common classical manifestations accompanied with spoon shaped nails, hyperpigmentation, oligodontia and hypotrichosis. The patients were treated for prosthetic rehabilitation and were asked to wear cool clothing. Key Words: Anodontia, Hypotrichosis, Hypohidrosis, Mutation, Sweat glands. 1 Department of Oral Pathology and Microbiology, Peoples Dental Academy, Bhopal, India 2 Department of Oral Pathology and Microbiology, D Y Patil University School of Dentistry, Navi Mumbai, India 3 Department of Oral Medicine and Radiology, Peoples Dental Academy, Bhopal, India Correspondence: Dr. Anish A Gupta, Department of Oral Pathology and Microbiology, Peoples Dental Academy, Bhopal, India E-mail: anishpooja687@yahoo.co.in Received: December 23, 2017; Accepted: October 10, 2018