Many people with abnormally large heads or large skulls are healthy, but macrocephaly may be pathological. Pathologic macrocephaly may be due to megalencephaly (enlarged brain), hydrocephalus (abnormally increased cerebrospinal fluid), cranial hyperostosis (bone overgrowth), and other conditions. Pathologic macrocephaly is called "syndromic", when it is associated with any other noteworthy condition, and "nonsyndromic" otherwise. Pathologic macrocephaly may be caused by congenital anatomic abnormalities, genetic conditions, or by environmental events. Many genetic conditions are associated with macrocephaly, including familial macrocephaly related to the holgate gene, autism, PTEN mutations such as Cowden disease, neurofibromatosis type 1, and tuberous sclerosis; overgrowth syndromes such as Sotos syndrome (cerebral gigantism), Weaver syndrome, Simpson-Golabi-Behmel syndrome (bulldog syndrome), and macrocephaly-capillary malformation (M-CMTC) syndrome; neurocardiofacial-cutaneous syndromes such as Noonan syndrome, Costello syndrome, Gorlin Syndrome, (also known as Basal Cell Nevus Syndrome) and cardiofaciocutaneous syndrome; Fragile X syndrome; leukodystrophies (brain white matter degeneration) such as Alexander disease, Canavan disease, and megalencephalic leukoencephalopathy with subcortical cysts; and glutaric aciduria type 1 and D-2-hydroxyglutaric aciduria. At one end of the genetic spectrum, duplications of chromosomes have been found to be related to autism and macrocephaly; at the other end, deletions of chromosomes have been found to be related to schizophrenia and microcephaly. Environmental events associated with macrocephaly include infection, neonatal intraventricular hemorrhage (bleeding within the infant brain), subdural hematoma (bleeding beneath the outer lining of the brain), subdural effusion (collection of fluid beneath the outer lining of the brain), and arachnoid cysts (cysts on the brain surface). In research, cranial height or brain imaging may be used to determine intracranial volume more accurately. Below is a list of causes of macrocephaly from Swaiman's Pediatric Neurology: Principles and Practice noted in The Little Black Book of Neurology: Hydrocephalus Dandy-Walker malformation Macrocephaly as a result of pediatric hydrocephalus, 1901 Noncommunicating * Arnold-Chiari malformation * Aqueductal stenosis * X-linked hydrocephalus with stenosis of the aqueduct of Sylvius (HSAS) syndrome (L1CAM) * Dandy-Walker malformation * Galenic vein aneurysm or malformation * Neoplasms, supratentorial, and infratentorial * Arachnoid cyst, infratentorial * Holoprosencephaly with dorsal interhemispheric sac Communicating * External or extraventricular obstructive hydrocephalus (dilated subarachnoid space) Arachnoid cyst, supratentorial Meningeal fibrosis/obstruction * Postinflammatory * Posthemorrhagic * Neoplastic infiltration Empyema Vascular * Arteriovenous malformation * Intracranial hemorrhage * Dural sinus thrombosis Choroid plexus papilloma Neurocutaneous syndromes * Incontinentia pigmenti Destructive lesions * Hydranencephaly * Porencephaly Familial, autosomal-dominant, autosomal-recessive, X-linked Hyperostosis Subdural fluid * Hematoma * Hygroma * Empyema Brain edema (toxic-metabolic) * Intoxication * Lead * Vitamin A * Tetracycline * Endocrine (hypoparathyroidism, hypoadrenocorticism) * Galactosemia * Idiopathic (pseudotumorcerebri) Thick skull or scalp (hyperostosis) Woman with macrocephaly caused by hyperostosis, 1894 * Familial variation * Anemia * Osteoporosis, severe precocious autosomal-recessive osteoporosis (CLCN7, TCIRG1) * Pycnodysostosis (CTSK) * Craniometaphyseal dysplasia (ANKH) * Craniodiaphyseal dysplasia * Pyle dysplasia * Sclerosteosis (SOST) * Juvenile Paget disease * Idiopathic hyperphosphatasia * Familial osteoectasia * Osteogenesis imperfecta * Rickets * Cleidocranial dysostosis * Hyperostosis corticalis generalisata (van Buchem disease) * Proteus syndrome Megalencephaly and hemimegalencephaly Hemimegalencephaly
symptom of Maroteaux–Lamy syndrome
symptom of Rotor syndrome
symptom of Tay–Sachs disease
symptom of Lesch–Nyhan syndrome
symptoms of Rotor syndrome
symptom of Bannayan–Riley–Ruvalcaba syndrome
symptom of Andersen–Tawil syndrome
symptom of Scheuermann's disease