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| {{SI}} | | {{Microcephaly}} |
| '''For patient information, click [[Microcephaly (patient information)|here]]''' | | '''For patient information, click [[Microcephaly (patient information)|here]]''' |
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| {{CMG}} | | {{CMG}} |
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| ==Overview== | | ==[[Microcephaly overview|Overview]]== |
| Microcephaly is a neurological disorder in which the circumference of the head is at least three [[standard deviations]] smaller than average for the person's age and sex. Microcephaly may be congenital or it may develop in the first few years of life.
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| ==Pathophysiology== | |
| The disorder may stem from a wide variety of conditions that cause abnormal growth of the brain, or from syndromes associated with chromosomal abnormalities. Two copies of a loss-of-function mutation in one of the ''[[microcephalin]]'' genes causes primary microcephaly.
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| '''Microcephaly''' is a disorder characterized by a small brain and may be caused by a disturbance in the proliferation of nerve cells. Microcephaly may also be associated with maternal problems such as [[alcoholism]] (which can result in the [[Fetal alcohol syndrome]] disability), diabetes, or [[rubella]] ([[German measles]]). A genetic factor may play a role in causing some cases of microcephaly. Affected newborns generally have striking neurological defects and seizures. Severely impaired intellectual development is common, but disturbances in motor functions may not appear until later in life.
| | ==[[Microcephaly historical perspective|Historical Perspective]]== |
| ==Causes== | |
| ===Common Causes===
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| #[[Anencephaly]]
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| #[[Cerebral atrophy]]; perinatal brain damage from [[hypoxia]]
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| #Congenital transplacental infection
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| #*[[Congenital toxoplasmosis]]
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| #*[[Congenital rubella syndrome]]
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| #*[[Congenital cytomegalovirus infection]]
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| #*[[Neonatal herpes]]
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| #*[[Congenital syphilis]]
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| #[[Craniosynostosis]] (total)
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| #[[Encephalocele]]
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| #[[Micrencephaly]] (idiopathic small brain)
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| ===Uncommon Causes=== | | ==[[Microcephaly classification|Classification]]== |
| {{MultiCol}}
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| *[[Aicardi Goutieres syndrome]]
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| *[[Allan-Herndon-Dudley syndrome]]
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| *[[Aminopterin fetopathy]]
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| *[[Anencephaly]]
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| *[[Angelman syndrome]]
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| *[[Arrhinencephaly]]
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| *[[Aspartylglucosaminuria]]
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| *[[Beckwith-Wiedemann syndrome]]
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| *[[Børjeson-Forssman-Lehman syndrome]]
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| *[[Brachmann-de Lange syndrome]] (de Lange syndrome)
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| *[[CAMFAK syndrome]]
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| *[[Cantu syndrome]]
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| *[[Cayler cardiofacial syndrome]]
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| *[[Cephaloskeletal dysplasia]] (Taybi-Linder syndrome)
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| *[[Cerebral atrophy; perinatal brain damage from hypoxia]]
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| *[[Cerebro-oculo-facio-skeletal syndrome ]](Pena–Shokein syndrome type II)
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| *[[Cerebrocostomandibular syndrome]]
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| *[[Ceroid lipofuscinosis, neuronal 1, infantile]]
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| *[[CHARGE syndrome]]
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| *[[Chondrodysplasia punctata ]](rhizomelic type)
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| *[[Christian syndrom ]]([[adducted thumbs syndrome)]]
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| *[[Chromosomal abnormalities]]
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| *[[Chromosome 14q deletion syndrome]]
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| *[[Chromosome 4 ring syndrome]]
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| *[[Chromosome 6 ring syndrome]]
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| *[[Chromosome 9 trisomy syndrome]]
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| *[[Chromosome syndromes ]]
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| *[[Cocaine abuse]]
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| *[[Cockayne syndrome]]
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| *[[Coffin-Siris syndrome]]
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| *[[Cohen syndrome]]
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| *[[Congenital transplacental infection ]]
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| *[[Cornelia de Lange syndrome]]
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| *[[Corpus callosum agenesis ]]type 2
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| *[[Craniosynostosis(total)]]
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| *[[Cri du chat syndrome]][[Cutis verticis gyrat]]
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| *[[Drug or poison ingestion]]
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| *[[Dubowitz syndrome]]
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| *[[Dyggve-Melchior-Clausen dysplasia]]
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| *[[Encephalocele]]
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| *[[Familial microcephaly]]
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| *[[Fanconi anaemia]]
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| *[[Feingold syndrome]]
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| *[[Fetal alcohol syndrome]]
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| *[[Fetal aminopterin-like syndrome]]
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| *[[Fetal hydantoin syndrome]](Dilantin embryopathy)
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| *[[Fetal trimethadione syndrome]]
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| *[[Fraser syndrome]] (cryptophthalmia syndrome)
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| *[[Freeman-Sheldon syndrome]] ([[whistling face syndrome]])
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| *[[Fumarase deficiency]]
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| *[[Galloway-Mowat syndrome]]
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| *[[Goltz syndrome]] (focal dermal hypoplasia)
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| *[[GOMBO syndrome]]
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| *[[Hischsprung disease-microcephaly-mental retardation syndrome]]
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| *[[Holoprosencephaly]]
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| *[[Homocystinuria]]
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| *[[Hoyeraal-Hreidarsson syndrome]]
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| *[[Incontinentia pigmenti]]
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| *[[Infantile Spasms - Microcephaly]]
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| *[[Johanson-Blizzard syndrome]]
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| *[[Juberg-Hayward syndrome]]
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| *[[Kearns-Sayre syndrome]]
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| *[[Krabbe disease]] (globoid cell leukodystrophy)
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| *[[Langer-Giedion syndrome]]
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| *[[Lathosterolosis]]
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| *[[Lenz microphthalmia syndrome]]
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| *[[Leprechaunism]]
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| *[[Lison syndrome]]
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| *[[Lissencephaly syndromes]] (congenital agyria)
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| *[[Lowry-Wood syndrome]]
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| *[[Malformations in neuronal migration - microcephaly]]
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| *[[Marinesco-Sjögren syndrome]]
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| *[[Gestational diabetes]]
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| *Maternal [[phenylketonuria]]
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| *[[Meckel syndrome]]
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| *[[Menkes syndrome]] ([[kinky-hair syndrome]])
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| *[[Methylenetetrahydrofolate reductase deficiency]]
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| *[[Mevalonate kinase deficiency]]
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| *[[Micrencephaly]] (idiopathic small brain)
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| *[[Microcephalic osteodysplastic dysplasia]]
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| *[[Microcephaly-lymphedema syndrome]]
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| *[[Mirhosseini-Holmes-Walton syndrome]]
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| *[[Neu-Laxova syndrome]]
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| *[[Nijmegen chromosome breakage syndrome]]
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| *[[Noonan syndrome]]
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| *[[Normal variant]]
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| *[[Norman-Roberts syndrome]]
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| *[[Oculo-auriculo-vertebral spectrum]] ([[Goldenhar-Gorlin syndrome]])
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| *[[Opitz trigonocephaly syndrome]] ([[C syndrome]])
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| *[[Osteoporosis-pseudoglioma syndrome]]
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| *[[Otopalatodigital syndrome type 2]]
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| *[[Pelizaeus-Merzbacher disease]]
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| *[[Phosphoehanolaminuria]]
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| *[[Pitt-Rogers-Danks syndrome]]
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| *[[Prader-Willi syndrome]]
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| *[[Prenatal radiation]]
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| {{ColBreak}}
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| *[[Progressive encephalopathy-edema-hypsarrhythmia-optic atrophy syndrome]]
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| *[[Pseudoprogeria syndrome]]
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| *[[Pseudotoxoplasmosis syndrome]]
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| *[[Pyruvate dehydrogenase deficiency]]
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| *[[Riley-Day syndrome]] ([[familial dysautonomia]])
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| *[[Rubinstein-Taybi syndrome]]
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| *[[Schizencephaly - microcephaly]]
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| *[[Seckel syndrome (bird-headed dwarfism)]]
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| *[[Seemanova syndrome 1]]
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| *[[Severe maternal malnutrition]]
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| *[[Smith-Lemli-Opitz syndrome]]
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| *[[Smith-McCort dysplasia]]
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| *[[Sutherland-Haan syndrome]]
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| *[[Syphilis]]
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| *[[Taybi-Linder syndrome]]
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| *[[Toluene]]
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| *[[Trichorhinophalangeal dysplasia]], type II (Langer-Giedion syndrome) and III (Ruvalcaba syndrom)
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| *[[Trisomy 13 syndrome]]([[Patau syndrome]])
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| *[[Trisomy 18 syndrome]]([[Edwards syndrome]])
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| *[[Trisomy 21 syndrome ]]([[Down syndrome]])
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| *[[Trisomy 22 syndrome]]
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| *[[Trisomy 9 syndrome]]
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| *[[Upton Young syndrome]]
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| *[[Van Maldergem Wetzburger Verloes syndrome]]
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| *[[Velocardiofacial syndrome]]
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| *[[Viljone Kallis Voges syndrome]]
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| *[[Waardenburg syndrome type 3]]
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| *[[Warburton Anyane Yeboa syndrome]]
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| *[[Weaver Williams syndrome]]
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| *[[Willems De vries syndrome]]
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| *[[Winship Viljoen Leary syndrome]]
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| *[[Wolf-Hirschhorn syndrome]]
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| *[[Worster-Drought syndrome]]
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| *[[Wrinkly skin syndrome]]
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| *[[X chromosome, duplication Xq13 1 q21 1 - Microcephaly]]
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| *[[X chromosome, trisomy Xp3 - Microcephaly]]
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| *[[X chromosome, trisomy Xq25 - Microcephaly]]
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| *[[X-linked mental retardation-hypotonic facies syndrome]]
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| *[[XXXXX syndrome]]
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| *[[Yunis-Varon syndrome]]
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| *[[Zerres Rietschel Majewski syndrome]]
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| *[[18: del 18q syndrome]]
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| *[[4: del 4p syndrome (Wolf-Hirschhorn syndrome)]]
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| *[[49,XXXXX syndrome]]
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| *[[7: del 7q syndrome]]
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| *[[9: dup 9p syndrome]]
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| {{EndMultiCol}}
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| ==Natural History, Complications, Prognosis== | | ==[[Microcephaly pathophysiology|Pathophysiology]]== |
| Microcephaly may be congenital or it may develop in the first few years of life. [[Infant|Infants]] with microcephaly are born with either a normal or reduced head size. Subsequently the head fails to grow while the face continues to develop at a normal rate, producing a child with a small head and a receding forehead, and a loose, often wrinkled scalp. As the child grows older, the smallness of the [[skull]] becomes more obvious, although the entire body also is often underweight and dwarfed. Development of motor functions and [[Speech communication|speech]] may be delayed. Hyperactivity and mental retardation are common occurrences, although the degree of each varies. Convulsions may also occur. Motor ability varies, ranging from clumsiness in some to spastic [[quadriplegia]] in others.
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| Some children will only have mild disability. Others, especially if they are otherwise growing and developing normally, will have normal intelligence and continue to develop and meet regular age-appropriate milestones.
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| ===Prognosis===
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| In general, life expectancy for individuals with microcephaly is reduced. The prognosis varies depending on the presence of associated abnormalities.
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| ==Diagnosis==
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| ===Physical Examination===
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| ====Head====
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| THe circumference of the head is smaller than 3 standard deviations below that of age sex matched individuals.
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| <div align="center">
| | ==[[Microcephaly causes|Causes]]== |
| <gallery heights="175" widths="175">
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| Image:Microcephaly 2.jpg|Diagram of microcephaly
| | ==[[Microcephaly epidemiology and demographics|Epidemiology and Demographics]]== |
| Image:Microcephaly.jpg|Microcephaly. Primer cause unknown
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| </gallery>
| | ==[[Microcephaly risk factors|Risk Factors]]== |
| </div>
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| <br>
| | ==[[Microcephaly screening|Screening]]== |
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| | ==[[Microcephaly natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
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| | == Diagnosis == |
| | [[Microcephaly history and symptoms| History and Symptoms]] | [[Microcephaly physical examination | Physical Examination]] | [[Microcephaly laboratory findings | Laboratory Findings]] | [[Microcephaly CT|CT]] | [[Microcephaly other diagnostic studies|Other diagnostic studies]] |
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| ==Treatment== | | ==Treatment== |
| Generally there is no specific treatment for microcephaly. Treatment is symptomatic and supportive.
| | [[Microcephaly medical therapy|Medical therapy]] | [[Microcephaly surgery|Surgery]] | [[Microcephaly primary prevention|Primary prevention]] | [[Microcephaly secondary prevention|Secondary prevention]] | [[Microcephaly cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Microcephaly future or investigational therapies|Future or Investigational Therapies]] |
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| | ==Case Studies== |
| | [[Microcephaly case study one|Case #1]] |
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| == See Also == | | ==Related Chapters== |
| * [[Hydrocephaly]] | | * [[Hydrocephaly]] |
| * [[Macrocephaly]] | | * [[Macrocephaly]] |
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| [[Category:Genetic disorders]] | | [[Category:Genetic disorders]] |
| [[Category:Nervous system]] | | [[Category:Nervous system]] |
| | [[Category:Medical signs]] |
| [[Category:Signs and symptoms]] | | [[Category:Signs and symptoms]] |
| [[Category:Pediatrics]] | | [[Category:Pediatrics]] |