Merck Manual

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Simeon A. Boyadjiev Boyd

, MD, University of California, Davis

Reviewed/Revised Sep 2022

There are two types of macrocephaly:

  • Disproportionate macrocephaly

  • Proportionate macrocephaly

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 Gigantism and Acromegaly Gigantism and acromegaly are syndromes of excessive secretion of growth hormone (hypersomatotropism) that are nearly always due to a pituitary adenoma. Before closure of the epiphyses, the result... read more Gigantism and Acromegaly ) should be considered.

General references

  • 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

  • 2. Fenichel, Gerald M: Clinical Pediatric Neurology: A Signs and Symptoms Approach, ed. 6. Philadelphia, Saunders/Elsevier, 2009, p. 369.

  • 3. Strassburg HM: Macrocephaly is not always due to hydrocephalus. J Child Neurol 4 Suppl:S32–S40, 1989. doi: 10.1177/0883073889004001s07


  • Prenatally, ultrasound

  • Postnatally, physical examination, including measurement of head circumference and cranial MRI

  • Genetic testing

Prenatally, the diagnosis of macrocephaly sometimes is made with routine ultrasonography done in the late second or early third trimester.

A clinical geneticist should evaluate affected patients even in cases of apparent isolated congenital anomaly. Chromosomal microarray analysis Diagnosis Chromosomal abnormalities cause various disorders. Abnormalities that affect autosomes (the 22 paired chromosomes that are alike in males and females) are more common than those that affect... read more , specific gene tests, or broader gene panel tests should be considered in the evaluation of patients with macrocephaly. If the results of these tests are nondiagnostic, whole exome sequencing analysis is recommended.

Developmental assessment should be done to identify need for any intervention to optimize developmental outcome.


  • Surgical repair

Currently, the majority of these craniofacial anomalies are treated surgically with the goal of restoring function and improving cosmetic appearance. Treatment and management are best done in tertiary medical centers by multidisciplinary teams capable of addressing all symptoms caused by the congenital anomaly.

Secondary complications (eg, increased intracranial pressure, amblyopia, dental misalignments, speech difficulties) should be managed by the appropriate specialists.

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