Musculoskeletal System ORGAN SYSTEMS


Occipitofrontal circumference > 2 SD above the mean for age and sex.



  • Benign familial
  • Neurocutaneous syndromes:
    • Neurofibromatosis, tuberous sclerosis, Sturge-Weber, Klippel-Trenaunay-Weber, linear sebaceous nevus
  • Others:
    • Sotos, Fragile X syndrome
  • Leukodystrophies:
    • Alexander, Canavan, megalencephalic leukoencephalopathy
  • Lysosomal storage diseases:
    • Tay-Sachs, mucopolysaccharidosis, gangliosidosis

Increased cerebrospinal fluid:

  • Hydrocephalus
  • Benign enlargement of subarachnoid space
  • Hydranencephaly, choroid plexus papilloma

Enlarged vascular compartment:

  • Arteriovenous malformation
  • Subdural, epidural, subarachnoid or intraventricular hemorrhage

Increase in bony compartment:

  • Bone disease:
    • Achondroplasia, osteogenesis imperfecta, osteopetrosis, hyperphosphatasia, cleidocranial dysostosis
  • Bone marrow expansion:
    • Thalassemia major

Miscellaneous causes:

  • Intracranial mass lesions:
    • Cyst, abscess or tumor
  • Raised intracranial pressure:
    • Idiopathic pseudotumor cerebri, lead poisoning, hypervitarninosis A, galactosemia

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