microphthalmos

Microphthalmia
	Classification and external resources
	Unilateral Microphthalmia
ICD-10	Q11.2
ICD-9	743.1
DiseasesDB	29618
eMedicine	oph/572
GeneReviews	Anophthalmia / Microphthalmia Overview;

小眼球症

関: microphthalmia

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/08/04 05:15:11」(JST)

wiki en

[Wiki en表示]

Microphthalmia also referred to as microphthalmos, nanophthalmia or nanophthalmos, is a developmental disorder of the eye that literally means small eye (micros = small; ophthalmos = eye). One (Unilateral Microphthalmia) or both (Bilateral Microphthalmia) eyes may be involved ^[1]

Presentation

The presence of a small eye within the orbit can be a normal incidental finding but in most cases it is abnormal and results in blindness. The incidence is 14 per 100,000 and the condition affects 3-11% of blind children.

Causes

Microphthalmia in newborns is sometimes associated with fetal alcohol syndrome^[1] or infections during pregnancy, particularly herpes simplex virus, rubella and cytomegalovirus (CMV), but the evidence is inconclusive. Genetic causes of microphthalmia include chromosomal abnormalities (trisomy 13 (Patau syndrome), Triploid Syndrome, and Wolf-Hirschhorn Syndrome) or monogenetic Mendelian disorders. The latter may be autosomal dominant, autosomal recessive or X linked. Genes that have been implicated in microphthamia include many transcription and regulatory factors. Those identified from family studies include the following:

HGNC symbol	Description	OMIM	Type
BCOR	BCL6 corepressor	300166	MCOPS2
CRYBA4	crystallin, beta A4
FOXE3	forkhead box E3
GDF6	growth differentiation factor 6
MITF	microphthalmia-associated transcription factor
OTX2	orthodenticle homeobox 2
PAX6	paired box 6
PITX3	Paired-like homeodomain transcription factor 3
RAX	retina and anterior neural fold homeobox
SHH	sonic hedgehog homolog
SIX6	SIX homeobox 6
SOX2	SRY (sex determining region Y)-box 2	206900	MCOPS3
VSX1	visual system homeobox 1 VSX1	visual system homeobox 1
RAB18	Ras-related protein 18
VSX2 (CHX10)	visual system homeobox 2

How these genes result in the eye disorder is unknown but it has been postulated that interference with the process of eye growth after birth may be involved in contrast to anophthalmia (absence of eyeball) which originates much earlier during foetal development. SOX2 has been implicated in a substantial number (10-15%) of cases and in many other cases failure to develop the ocular lens often results in microphthamia. Microphthalmia-associated transcription factor (MITF) located on chromosome 14q32 is associated with one form of isolated microphthalmia (MCOP1. In mammals the failure of expression of the transcription factor, MITF (microphthalmia-associated transcription factor), in the pigmented retina prevents this structure from fully differentiating. This in turn causes a malformation of the choroid fissure of the eye, resulting in the drainage of vitreous humor fluid. Without this fluid, the eye fails to enlarge, thus the name microphthalmia.The gene encoding the microphthalmia-associated transcription factor (MITF) is a member of the basic helix-loop-helix-leucine zipper (bHLH-ZIP) family. Waardenburg syndrome type 2 (WS type 2) in humans is also a type of microphthalmia syndrome. Mutations in MITF gene are thought to be responsible for this syndrome. The human MITF gene is homologous to the mouse MITF gene (aka mouse mi or microphthalmia gene); mouse with mutations in this gene are hypopigmented in their fur. The identification of the genetics of WS type 2 owes a lot to observations of phenotypes of MITF mutant mice.

References

^ ^a ^b "Definition of Micropthalmia". MedicineNet. Retrieved 2009-01-01.

External links

GeneReviews/NCBI/NIH/UW entry on Anophthalmia / Microphthalmia Overview
Parent Support group for parents with Anophthalmic and Microphthalmic children MAPS
Anophthalmia and Microphthalmia Resource Guide from the National Eye Institute (NEI).
GeneReviews/NCBI/NIH/UW entry on Microphthalmia with Linear Skin Defects Syndrome
MACS The Micro and Anophthalmic Children's Society - Offers support and Information to families in the UK and around the world
Ensembl
HUGO Gene Nomenclature Committee
OMIM-Online Mendelian Inheritance in Man

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 視神経の先天性および後天性異常 congenital anomalies and acquired abnormalities of the optic nerve
2. 先天性奇形に対するアプローチ approach to congenital malformations
3. 白色瞳孔を有する小児に対するアプローチ approach to the child with leukocoria
4. 黒色腫（メラノーマ）の分子生物学 the molecular biology of melanoma
5. 黒色腫（メラノーマ）における所属リンパ節の病理学的評価 pathologic evaluation of regional lymph nodes in melanoma

English Journal

3D Orbital Reconstruction in a Patient with Microphthalmos and a Large Orbital Cyst-A Case Report.

Mourits DL1, Wolff J2, Forouzanfar T2, Ridwan-Pramana A2, Moll AC1, de Graaf P3, Remmers JS4, Kraal-Biezen E1, Hartong DT1.
Ophthalmic genetics.Ophthalmic Genet.2016 Jun;37(2):233-7. doi: 10.3109/13816810.2015.1033558. Epub 2016 Jan 13.
BACKGROUND: Orbital cysts are rare developmental anomalies that can occur in microphthalmic and anophthalmic patients. Such cysts can promote orbital growth and subsequently markedly increase the size of the orbit, which is commonly underdeveloped in these patients. Cyst removal is therefore general
PMID 26760736

PHACE syndrome with lip haemangioma, microphthalmos and persistent fetal vasculature.

Nayak L1, Nayak B2, Sinha G3, Khokhar S3.
BMJ case reports.BMJ Case Rep.2016 Mar 31;2016. pii: bcr2016214724. doi: 10.1136/bcr-2016-214724.
An 11-month-old baby girl presented with white reflex in her left eye. On examination, there was a 6.5×5 mm(2)haemangioma present over her face involving on her lower lip. Systemic examinations were within normal limits. The left eye was small, with an axial length of 16.08 mm and had a catarac
PMID 27033295

Failure to Target RANKL Signaling Through p38-MAPK Results in Defective Osteoclastogenesis in the Microphthalmia Cloudy-Eyed Mutant.

Carey HA1, Bronisz A2, Cabrera J1, Hildreth BE 3rd1,3, Cuitiño M1, Fu Q1, Ahmad A1, Toribio RE3, Ostrowski MC1, Sharma SM1.
Journal of cellular physiology.J Cell Physiol.2016 Mar;231(3):630-40. doi: 10.1002/jcp.25108.
The Microphthalmia-associated transcription factor (MITF) is a basic helix-loop-helix leucine zipper family factor that is essential for terminal osteoclast differentiation. Previous work demonstrates that phosphorylation of MITF by p38 MAPK downstream of Receptor Activator of NFkB Ligand (RANKL) si
PMID 26218069

Japanese Journal

Novel compound heterozygous mutations in the MFRP gene in a Japanese patient with posterior microphthalmos

Matsushita Itsuka,Kondo Hiroyuki,Tawara Akihiko
Japanese journal of ophthalmology 56(4), 396-400, 2012-07-01
NAID 10030952220

Survey of microphthalmia in Japan

Nishina Sachiko,Kurosaka Daijiro,Nishida Yasuhiro [他],KONDO Hiroyuki,KOBAYASHI Yuri,AZUMA Noriyuki
Japanese journal of ophthalmology 56(3), 198-202, 2012-05-01
NAID 10030626740

小眼球症の小児2症例の黄斑部OCT所見

三原美晴,中村友子,藤田和也,宮腰晃央,林篤志
眼科臨床紀要 = Folia Japonica de ophthalmologica clinica 4(5), 442-447, 2011-05-15
NAID 10031162548

匿名

検索

案内

案内