|Year : 2015 | Volume
| Issue : 2 | Page : 93-95
BM Shashikumar, MR Harish, Shweta P Bhadbhade, K Deepadarshan
Department of Dermatology, Mandya Institute of Medical Sciences, Mandya, Karnataka, India
|Date of Web Publication||9-Apr-2015|
Shweta P Bhadbhade
Department of Dermatology, No. 13, OPD Block, Mandya Institute of Medical Sciences, Mandya 571 401, Karnataka
Source of Support: None, Conflict of Interest: None
Cooks syndrome is an autosomal dominant ectodermal dysplasia. It is characterized by congenital onychodystrophy and anonychia along with fifth finger brachydactyly, digitalization of the thumb, absent or hypoplastic distal phalanges of hands and feet with normal hair, teeth and sweat glands. Anonychia involving all the 20 digits is a rare occurrence. Here we report a 4 day old male baby with congenital anonychia of all 20 digits along with digitalization of the thumb.
Keywords: Anonychia, autosomal dominant, Cooks syndrome, onychodystrophy
|How to cite this article:|
Shashikumar B M, Harish M R, Bhadbhade SP, Deepadarshan K. Cooks syndrome. Indian J Paediatr Dermatol 2015;16:93-5
| Introduction|| |
Cooks syndrome is an autosomal dominant ectodermal dysplasia. It is characterized by congenital onychodystrophy and anonychia along with fifth finger brachydactyly, digitalization of the thumb, absent/hypoplastic distal phalanges of hands and feet with normal hair, teeth and sweat glands.  Cook's syndrome is listed as a "rare disease" by the office of rare diseases of National Institutes of Health.  Here, we report a 4-day-old baby with congenital anonychia of all the digits along with other features consistent with Cook's syndrome.
| Case report|| |
A 4-day-old male baby presented with congenital absence of nails involving all the fingers and toes. The baby is a second child born to a consanguineously married couple (second degree). The prenatal and natal history was uneventful with normal anomaly scan and growth scans. There was no history of drug intake during pregnancy or any other interventions. The baby was born by normal vaginal delivery with birth weight of 1.8 kg, normal APGAR score and normal cry. There was no similar history in the first child and other family members.
On examination, there was anonychia affecting all 20 digits, except for a small bud of nail on right 3 rd toe [Figure 1] and [Figure 2]. There was digitalization of both thumbs. The fingers with anonychia felt very soft and compressible at their tips. There was bulbous swelling at the tips of both the great toes [Figure 2]. No other skeletal anomaly was detected. Sexual development was normal. No facial anomaly was detected. Hair and mucous membrane did not reveal any abnormality. The anterior fontanalle was normal for age. Radiography revealed the absence of distal phalanges of all the fingers and toes [Figure 3] and [Figure 4]. Metacarpals and metatarsals were normal on both sides. Radiographs of bilateral forearms and legs were normal.
|Figure 2: Anonychia and bulbous swelling of right toe nails with a small bud of nail seen on 3rd toe|
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|Figure 4: Radiograph of right hand showing absence of distal phalanges and triphalangism of thumb. Metacarpals and bones of forearm appear normal|
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Brachydactyly A, brachydactyly B and mammary-digital-nail syndrome were considered for the differential diagnosis. In brachydactyly B syndrome, there will be amputation like lesions of digits; hypo/aplasia of distal phalanges, nail hyponychia or anonychia with sparing of thumbs in the classic form, but many appear broadened or bifid in severe cases. Absence of middle phalanges; various nail dysplasias of digits 2-5 of hands and feet is a feature of Brachydactyly A syndrome,  whereas juvenile hypertrophy of the breast in association with onychodystrophy with hypoplasia or absence of distal phalanges (ODP) in female child and only ODP in males is a presentation in mammary-digital-nail syndrome. As most of the clinical findings in our case are favorable for Cooks syndrome, the diagnosis of Cooks syndrome was made.
| Discussion|| |
Nail development begins at 8-10 weeks of intrauterine life (IUL) and is completed by 5 th month. The flat rectangular surface of the future nail bed on the dorsal tips is first demarcated by folds visible at 8-10 weeks of IUL.  Though the exact etiology of anonychia is not known, molecular genetics reveals microduplications on chromosome 17q24.3 involving non coding element of SOX9 gene resulting in an abnormal digit and nail development. 
Cooks et al. described a kindred in which seven individuals in two generations with one instance of male-to-male transmission had a disorder characterized by onychodystrophy, anonychia, brachydactyly of the fifth finger, and digitalization of the thumbs, with absence or hypoplasia of the distal phalanges of the hands and feet. This disorder differed from autosomal dominant anonychia-onychodystrophy in which there is progressive nail hypoplasia from the fifth digit to the thumb, with anonychia often present in the second and third digits. In addition, in dominant anonychia-onychodystrophy, no bone changes had been described. In autosomal dominant brachydactyly with absence of middle phalanges and hypoplastic nails, the changes in the middle phalanges are distinctive. In an entity called "20-nail dystrophy," dystrophy of the nails progresses with age.  A similar case of congenital anonychia and brachydayly of the left foot was reported as a possibility of a variant of Cooks syndrome in a 45-year-old male. 
To conclude, Cook's syndrome is a rare autosomal dominant ectodermal dysplasia. To date, only 20 cases have been described in world literature.  Hence, it is very important for the dermatologist to know about anonychia and counsel the parents regarding the prognosis of this rare entity.
| References|| |
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]