Macrocephaly

(See also Introduction to Congenital Craniofacial and Musculoskeletal Disorders Introduction to Congenital Craniofacial and Musculoskeletal Abnormalities Craniofacial and musculoskeletal abnormalities are common among children. They may involve only a single, specific site (eg, cleft lip, cleft palate, clubfoot) or be part of a syndrome of multiple... read more and Overview of Congenital Craniofacial Abnormalities Overview of Congenital Craniofacial Abnormalities Congenital craniofacial abnormalities are a group of defects caused by abnormal growth and/or development of the head and facial soft-tissue structures and/or bones. (See also Introduction to... read more .)

There are two types:

In disproportionate macrocephaly, the head is larger than appropriate for the child's size; affected children are at risk of autism spectrum disorders, developmental disability, and seizures.

In proportionate macrocephaly, the head appears appropriately sized for the body (ie, the large head is associated with a large stature), and an overgrowth syndrome (eg, growth hormone excess) should be considered.

Abnormal macrocephaly may be due to an enlarged brain (megalencephaly), hydrocephalus Hydrocephalus Hydrocephalus is accumulation of excessive amounts of CSF, causing cerebral ventricular enlargement and/or increased intracranial pressure. Manifestations can include enlarged head, bulging... read more , cranial hyperostosis, or other conditions. These conditions may be the result of genetic disorders or disorders the child acquired before or after birth ( 3 General references Macrocephaly (megacephaly) is a head circumference > 2 standard deviations above the mean for age ( 1, 2). (See also Introduction to Congenital Craniofacial and Musculoskeletal Disorders and... read more ).

Evaluation should include a 3-generation family history, developmental and neurologic assessment, examination for limb asymmetry and cutaneous lesions, and brain MRI. Sometimes disproportionate macrocephaly is familial and not associated with other anomalies, complications, or developmental delays; this form is transmitted in an autosomal dominant pattern, so at least one parent has a large head circumference. The diagnoses to be considered include neurofibromatosis type 1 Neurofibromatosis Neurofibromatosis refers to several related disorders that have overlapping clinical manifestations but that are now understood to have distinct genetic causes. It causes various types of benign... read more , Fragile X syndrome Fragile X Syndrome Fragile X syndrome is a genetic abnormality on the X chromosome that leads to intellectual disability and behavioral disorders. Diagnosis is with molecular DNA analysis. Treatment is supportive... read more , Sotos syndrome, and lysosomal storage disorders Overview of Lysosomal Storage Disorders Lysosomal enzymes break down macromolecules, either those from the cell itself (eg, when cellular structural components are being recycled) or those acquired outside the cell. Inherited defects... read more .