(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...
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, 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...
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).
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...
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, 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...
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, 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...
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.
General references
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1. Cogulu O, Aykut A, Kutukculer N, et al: Two cases of macrocephaly and immune deficiency. Clin Dysmorphol 16(2):81–84, 2007. doi: 10.1097/MCD.0b013e3280464ee6.
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2. Fenichel, Gerald M: Clinical Pediatric Neurology: A Signs and Symptoms Approach, ed. 6. Philadelphia, Saunders/Elsevier, 2009, p. 369.
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3. Strassburg HM: Macrocephaly is not always due to hydrocephalus. J Child Neurol 4 Suppl:S32–S40, 1989. doi: 10.1177/0883073889004001s07.
