1. Hair collar sign
BY:
MOHAMMED ALSAIDAN

2. Hair collar sign
Ring-like hypertrichosis consisting of coarser and longer hair surrounding a congenital alopecic lesion on the midline of the scalp.
A marker of cranial dysraphism, including encephaloceles, meningoceles, Cutaneous meningothelial tumors (heterotropic brain tissue), dermoid cyst , aplasia cutis congenita, Dandy Walker malformation or agenesis of the corpus callosum
Due to neuroectodermal abnormalities in embryonic development of the cranial neural tube
resulting in down-regulation of pathogenic antibodies production .
Fc Fc (Fragment, crystallizable) region
Fab antigen binding

5. Hair collar sign
Encephaloceles and meningoceles communicate directly to the central nervous system by herniation of intracranial structures through a scalp defect
Heterotropic brain tissue is found with an intact cranium and no connection to the brain
complex interaction between epithelium and mesenchyma nerve tissue stimulates hair growth
greater density of hair could be explained by the displacement of follicles at the lesion’s border

6. Associations Port wine stain Subcutaneous hemangioma
the presence of a vascular malformation with a second cutaneous marker heightens the likelihood of dysraphism
Cardiac defect ( e.g. VSD)
Oculoectodermal syndrome : include epibulbar dermoids and other ocular abnormalities, skin hyperpigmentation, congenital heart defects, urinary tract malformations, and neoplasms
Syndactyly , cleft lip and palate, sclerocornea, scalp epidermal nevus, lipodermoid also have been reported
resulting in down-regulation of pathogenic antibodies production .
Fc Fc (Fragment, crystallizable) region
Fab antigen binding

15. Approach Present at birth ? Growing in size ? Bulging with crying ?
Thorough physical examination with neurologic evaluation
Brain MRI
Screening for spinal abnormalities (spine, spinal cord)
Genetic counseling ? Translocation t(1;4) (q44;q10).
Abdominal ultrasound, metabolic screening
resulting in down-regulation of pathogenic antibodies production .
Fc Fc (Fragment, crystallizable) region
Fab antigen binding