ectodermal dysplasia ( ed ) are group of inherited disorders involving the developmental defects of ectodermal structure with an incidence of 1 in 1,00,000 live births .
this group of inheritable disorders are characterized by an abnormality of two or more structures derived from ectoderm such as the hair , teeth , nails , sweat glands , craniofacial structures , digits , and others .
the x - linked recessive is the most common pattern of inheritance while autosomal dominant and recessive are rare . in few cases ,
review of the literature revealed few case reports in the living individuals however to the best of our knowledge this is the first description of perinatal autopsy findings in a case of ed .
a 21-year - old primigravida with 28 weeks of gestation , presented with a history of not appreciating fetal movements since 2 days .
there was no history of fever with rashes during pregnancy and no history of any drug intake except iron and folic acid supplements .
sonography revealed the absence of fetal cardiac activity and intrauterine growth retardation . after obtaining consent ,
the pregnancy was terminated and the fetus was sent for pathological examination . on gross examination , fetus weighed 700 g. all the fetal measurements were within normal limits . a tiny piece of umbilical cord attached to the fetus showed two vessels .
the fetus had potter 's facies that is low set ears , depressed nasal bridge , and increased intercanthal distance .
an orthopantomogram was done , which revealed decreased calcification and absence of tooth buds in many sockets ( oligodontia ) [ figure 1d ] .
( a ) gross photograph showing sparse hair on scalp and absence of lips , ( b ) gross photograph showing sparse hair on chest , absence of nipple and skin deficient areas on left elbow joint .
( c ) gross photograph showing skin deficient areas on right elbow joint and right hand .
( e ) microphotograph of skin showing thinned out epidermis , immature hair follicle , and absence of sweat glands ( h and e , 10 ) .
( f ) microphotograph of skin showing negative immunostaining for herpes simplex virus ( hsv ) antibody ( ihc hsv , 10 ) on dissection , all organs are in situs except left kidney which was malrotated and nonascended to the left lumbar region .
the capsule was easily strippable and fetal lobulations were present . in the thorax , the lungs appeared hypoplastic and the heart was normal in development .
the hair follicles were decreased in number and were immature ( hypotrichosis ) , the sweat glands were absent [ figure 1e ] .
immunohistochemical ( ihc ) staining for herpes simplex virus ( hsv ) was carried out on skin sections and was negative [ figure 1f ] .
histopathological section of the skin from age and sex matched fetus studied , which showed normal development of epidermis and adnexal structure thus confirming the nondevelopment of skin and its appendages in the present fetus . with the above features , a final diagnosis of hypohidrotic ed was made .
weech first used the term hereditary ed to describe the congenital anomalies affecting the ectodermal structure . in 1838 ,
wedderburn 's reported ed in 10 men in a hindu family the highlight being x - linked recessive inheritance and oligodontia in the family .
cockyane in 1933 postulated x - linked recessive inheritance in families where only males were affected and autosomal dominant if female also manifested the features .
it was levit in 1936 who pointed out that females never exhibit full syndrome , hence opening up a new possibility of de novo mutation .
ectodermal dysplasia is commonly transmitted as x - linked recessive pattern with autosomal dominant and recessive being rare .
the defective genes that are associated with ed are ed-1 , muscle segment homeobox homology-1 , ectodysplasia-1 ( edar ) , and paired box gene ( pax 9 ) .
, observed a new genetic locus of ed , the protein product is 135 residue transmembrane protein and is predicted to belong to noval class with a role in epithelial and mesenchymal signaling .
monreal et al . in their study isolated human homolog of mouse dl ( human dl ) in three families , one displaying recessive inheritance and two displaying dominant inheritance .
the putative protein is predicted to have single transmembrane domain and is similar to tumor necrosis factor receptor family .
organogenesis is a complex process that occurs due to synergistic interaction between ectoderm and mesoderm .
the genes ed , edar and others synergistically act to produce protein ectodysplasin-1 , which forms a part of signaling pathway that is critical for the interaction between ectoderm and mesoderm .
with respect to ectodermal derived structure , 6 week of embryonic life is critical , as at this point the single layer of ectoderm divides into two cell layer leading to subsequent organ development .
dental lamina also begins at 6 week ; hence , any mutation at this point leads to a severe form of ed involving all the ectodermal structure along with teeth .
( as observed in our case ) ectodermal dysplasia are primarily classified into four different types , ed1 ( trichodysplasia ) , ed2 ( dental dysplasia ) , ed3 ( onychodysplasia ) , and ed4 ( dyshidrosis ) . from these major types
150 different combinations of subtypes are classified , most common being subtype 1 - 2 - 3 - 4 involving all the structures that is , hypohidrotic ed .
skin is usually thin , soft and dry ( as observed in our case ) .
there is hyperkeratosis of palm and foot . there is wrinkling and pigmentation around the eyes and mouth .
hair over the scalp is often blond , fine , stiff , and short ( as observed in our case ) .
other rare abnormalities recorded with ed are frontal bossing , depression of the nasal bridge , small face , central nervous system defects , and adrenal medullary defects .
the pharyngeal , laryngeal , oral , and nasal mucosal glands are defective leading to dryness and repeated infections .
our case in addition to classical abnormalities highlighted the absence of nipple , nails , and lips , which may be due to the severe mutation involving the genes .
testing of lacrimal gland sections , skin biopsy , sweat pore test , and molecular tests help in diagnosis of the condition in the living .
sweat pore test in addition to detect the affected individuals also helps in identification of carriers . in suspected cases ,
a near complete work up was done and hsv , which is known to cause defective embryogenesis has been ruled out .
based on morphology and histological finding we arrived at a diagnosis of hypohidrotic ed with a possibility of de novo mutation .
ectodermal dysplasia is rare disorder and its presentation in a female fetus on autopsy makes it even rarer .
such rare case beckons a thorough evaluation with family history , radiological , and ihc methods along with genetic counseling .
 ectodermal dysplasia are group of inherited disorders involving the developmental defects of ectodermal structures like hair , teeth , nails , sweat glands , and others . 
 x - linked recessive inheritance is most common . here 
 we describe perinatal autopsy findings in a case of de novo ectodermal dysplasia in a female fetus . to the best of our knowledge , 
 this is the first fetal autopsy description in a case of ectodermal dysplasia . 
INTRODUCTION
CASE REPORT
DISCUSSION
CONCLUSION