WordNet

not perfect; defective or inadequate; "had only an imperfect understanding of his responsibilities"; "imperfect mortals"; "drainage here is imperfect"
the developmental process of forming tooth enamel

PrepTutorEJDIC

『完全でない』,欠陥のある / (過去時制で動詞が)未完了の / 未完了時制

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/09/19 01:21:18」(JST)

wiki en

Amelogenesis imperfecta (AI) presents with a rare abnormal formation of the enamel^[1] or external layer of the crown of teeth. Enamel is composed mostly of mineral, that is formed and regulated by the proteins in it. Amelogenesis imperfecta is due to the malfunction of the proteins in the enamel: ameloblastin, enamelin, tuftelin and amelogenin.

People afflicted with amelogenesis imperfecta have teeth with abnormal color: yellow, brown or grey; this disorder can afflict any number of teeth of both dentitions. The teeth have a higher risk for dental cavities and are hypersensitive to temperature changes as well as rapid attrition, excessive calculus deposition, and gingival hyperplasia.^[2]

Genetics

Mutations in the AMELX,^[3] ENAM,^[4] MMP20,^[5] KLK-4,^[6] FAM83H,^[7] WDR72,^[8] C4orf26,^[9] SLC24A4 ^[10] LAMB3 ^[11] and ITGB6 ^[12] genes have been found to cause amelogenesis imperfecta (non-syndromic form). AMELX and ENAM encode extracellular matrix proteins of the developing tooth enamel and KLK-4 and MMP20 encode proteases that help degrade organic matter from the enamel matrix during the maturation stage of amelogenesis. SLC24A4 encodes a calcium transporter that mediates calcium transport to developing enamel during tooth development. Less is known about the function of other genes implicated in amelogenesis imperfecta.

Researchers expect that mutations in further genes are likely to be identified as causes of amelogenesis imperfecta.Types include:

Type	OMIM	Gene	Locus
AI1B	104500	ENAM	4q21
AI1C	204650	ENAM	4q21
AI2A1	204700	KLK4	19q13.4
AI2A2	612529	MMP20	11q22.3-q23
AI2A3	613211	WDR72	15q21.3
AI2A4	614832	C4orf26	4q21.1
AI2A5	609840	SLC24A4	14q32.12
AI3	130900	FAM83H	8q24.3
AIH1	301200	AMELX	Xp22.3-p22.1
AIGFS	614253	FAM20A	17q24.2

Amelogenesis imperfecta can have different inheritance patterns depending on the gene that is altered. Mutations in the ENAM gene are the most frequent known cause and are most commonly inherited in an autosomal dominant pattern. This type of inheritance means one copy of the altered gene in each cell is sufficient to cause the disorder.

Amelogenesis imperfecta is also inherited in an autosomal recessive pattern; this form of the disorder can result from mutations in the ENAM, MMP20, KLK4, FAM20A, C4orf26 or SLC24A4 genes. Autosomal recessive inheritance means two copies of the gene in each cell are altered.

About 5% of amelogenesis imperfecta cases are caused by mutations in the AMELX gene and are inherited in an X-linked pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes. In most cases, males with an X-linked form of this condition experience more severe dental abnormalities than affected females.Recent genetic studies suggest that the cause of a significant proportion of amelogenesis imperfecta cases remains to be discovered.^{[citation needed]}

Treatment

X-ray showing lack of enamel opacity and a pathological loss of enamel in patient with amelogenesis imperfecta

Preventive and restorative dental care is very important as well as considerations for esthetic issues since the crown are yellow from exposure of dentin due to enamel loss.^[2] Full-coverage crowns are sometimes being used to compensate for the abraded enamel. Usually stainless steel crowns are used in children which may be replaced by porcelain once they reach adulthood.^[13] In the worst-case scenario, the teeth may have to be extracted and implants or dentures are required. Loss of nerves in the affected teeth may occur.

Epidemiology

The exact incidence of amelogenesis imperfecta is uncertain. Estimates vary widely, from 1 in 700 people in northern Sweden to 1 in 14,000 people in the United States.

References

^ Pieter J. Slootweg (2007). Dental pathology: a practical introduction. Springer Science & Business Media. pp. 19–. ISBN 978-3-540-71690-7. Retrieved 28 December 2010.
^ ^a ^b American Academy of Pediatric Dentistry, Guideline on Dental Management of Heritable Dental Developmental Anomalies, 2013, http://www.aapd.org/media/Policies_Guidelines/G_OHCHeritable.pdf
^ Lagerström M, Dahl N, Nakahori Y, Nakagome Y, Bäckman B, Landegren U, Pettersson U (1991). "A deletion in the amelogenin gene (AMG) causes X-linked amelogenesis imperfecta (AIH1)". Genomics. 10 (4): 971–975. doi:10.1016/0888-7543(91)90187-j. PMID 1916828.
^ Rajpar MH.; Harley K; Laing C; Davies RM; Dixon MJ (2001). "Mutation of the gene encoding the enamel-specific protein, enamelin, causes autosomal-dominant amelogenesis imperfecta". Hum. Mol. Genet. 10 (16): 1673–1677. doi:10.1093/hmg/10.16.1673. PMID 11487571.
^ Kim JW, Simmer JP, Hart TC, Hart PS, Ramaswami MD, Bartlett JD, Hu JC (2005). "MMP-20 mutation in autosomal recessive pigmented hypomaturation amelogenesis imperfecta". J. Med. Genet. 42: 271–275. doi:10.1136/jmg.2004.024505. PMC 1736010. PMID 15744043.
^ Hart PS, Hart TC, Michalec MD, Ryu OH, Simmons D, Hong S (2004). "Mutation in kallikrein 4 causes autosomal recessive hypomaturation amelogenesis imperfecta". J. Med. Genet. 41 (7): 545–549. doi:10.1136/jmg.2003.017657. PMC 1735847. PMID 15235027.
^ Kim JW, Lee SK, Lee ZH, Park JC, Lee KE, Lee MH, Park JT, Seo BM, Hu JC, Simmer JP (2008). "FAM83H mutations in families with autosomal-dominant hypocalcified amelogenesis imperfecta". Am. J. Hum. Genet. 82: 489–494. doi:10.1016/j.ajhg.2007.09.020. PMC 2427219. PMID 18252228.
^ El-Sayed W, Parry DA, Shore RC, Ahmed M, Jafri H, Rashid Y, Al-Bahlani S, Al Harasi S, Kirkham J, Inglehearn CF, Mighell AJ (2009). "Mutations in the beta propeller WDR72 cause autosomal-recessive hypomaturation amelogenesis imperfecta". Am. J. Hum. Genet. 85: 699–705. doi:10.1016/j.ajhg.2009.09.014. PMC 2775821. PMID 19853237.
^ Parry DA, Brookes SJ, Logan CV, Poulter JA, El-Sayed W, Al-Bahlani S, Al Harasi S, Sayed J, Raïf M, Shore RC (2012). "Mutations in C4orf26, Encoding a Peptide with In Vitro Hydroxyapatite Crystal Nucleation and Growth Activity, Cause Amelogenesis Imperfecta". Am. J. Hum. Genet. 91: 565–571. doi:10.1016/j.ajhg.2012.07.020. PMID 22901946.
^ Parry DA, Poulter JA, Logan CV, Brookes SJ, Jafri H, Ferguson CH, Anwari BM, Rashid Y, Zhao H, Johnson CA, Inglehearn CF, Mighell AJ (2013). "Identification of mutations in SLC24A4, encoding a potassium-dependent sodium/calcium exchanger, as a cause of amelogenesis imperfecta". Am. J. Hum. Genet. 92 (2): 307–312. doi:10.1016/j.ajhg.2013.01.003. PMID 23375655.
^ Poulter JA, El-Sayed W, Shore RC, Kirkham J, Inglehearn CF, Mighell AJ (2013). "Whole-exome sequencing, without prior linkage, identifies a mutation in LAMB3 as a cause of dominant hypoplastic amelogenesis imperfecta". Eur. J. Hum. Genet. 22 (1): 132–5. doi:10.1038/ejhg.2013.76. PMID 23632796.
^ Wang SK, Choi M, Richardson AS, Reid BM, Lin BP, Wang SJ, Kim JW, Simmer JP, Hu JC (2014). "ITGB6 loss-of-function mutations cause autosomal recessive amelogenesis imperfecta". Hum. Mol. Genet. 23 (8): 2157–63. doi:10.1093/hmg/ddt611. PMC 3959820. PMID 24305999.
^ Illustrated Dental Embryology, Histology, and Anatomy, Bath-Balogh and Fehrenbach, Elsevier, 2011, page 64

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. 歯の発達障害 developmental defects of the teeth

English Journal

Bmp2 deletion causes an amelogenesis imperfecta phenotype via regulating enamel gene expression.

Guo F1, Feng J, Wang F, Li W, Gao Q, Chen Z, Shoff L, Donly KJ, Gluhak-Heinrich J, Chun YH, Harris SE, MacDougall M, Chen S.
Journal of cellular physiology.J Cell Physiol.2015 Aug;230(8):1871-82. doi: 10.1002/jcp.24915.
Although Bmp2 is essential for tooth formation, the role of Bmp2 during enamel formation remains unknown in vivo. In this study, the role of Bmp2 in regulation of enamel formation was investigated by the Bmp2 conditional knock out (Bmp2 cKO) mice. Teeth of Bmp2 cKO mice displayed severe and profound
PMID 25545831

Novel FAM20A mutation causes autosomal recessive amelogenesis imperfecta.

Volodarsky M1, Zilberman U2, Birk OS3.
Archives of oral biology.Arch Oral Biol.2015 Jun;60(6):919-22. doi: 10.1016/j.archoralbio.2015.02.018. Epub 2015 Feb 28.
OBJECTIVE: To relate the peculiar phenotype of amelogenesis imperfecta in a large Bedouin family to the genotype determined by whole genome linkage analysis.DESIGN: Amelogenesis imperfecta (AI) is a broad group of inherited pathologies affecting enamel formation, characterized by variability in phen
PMID 25827751

Japanese Journal

Dandy-Walker variantの患児に歯の形成不全症の合併が疑われた1例

小児歯科学雑誌 52(3), 440-447, 2014
NAID 130005084436

エナメル質形成不全症の新規責任遺伝子変異の発見とその意義 : 転写因子Sp6をめぐるパズル

四国歯学会雑誌 26(1), 1-10, 2013-07-17
NAID 120005832477

片側側方歯開咬を伴う遺伝性エナメル質形成不全症の1例

齒科學報 113(3), 276-283, 2013-06-30
NAID 10031182966

Related Pictures

★リンクテーブル★

リンク元	「エナメル質形成不全」「hypoplastic enamel」「dental enamel hypoplasia」「エナメル質形成不全症」
関連記事	「imperfect」「imperfecta」

「エナメル質形成不全」

Amelogenesis imperfecta
	Amelogenesis imperfecta, hypoplastic type. Note the association of pitted enamel and open bite.
Classification and external resources
ICD-10	K00.5
ICD-9-CM	520.5
DiseasesDB	31408
MedlinePlus	001578
	[edit on Wikidata]

　　[★]

ラ: amelogenesis imperfecta、enamel hypoplasia、hypoplastic enamel、dental enamel hypoplasia
関: エナメル質形成不全症、歯牙エナメル質形成不全

「hypoplastic enamel」

　　[★]

エナメル質形成不全、エナメル質形成不全症

関: amelogenesis imperfecta、dental enamel hypoplasia、enamel hypoplasia

「dental enamel hypoplasia」

　　[★]

歯牙エナメル質形成不全、エナメル質形成不全

関: amelogenesis imperfecta、enamel hypoplasia、hypoplastic enamel

「エナメル質形成不全症」

　　[★]

ラ: amelogenesis imperfecta、hypoplastic enamel
関: エナメル質形成不全、歯牙エナメル質形成不全

「imperfect」

　　[★]

adj.

不完全な

関: defective、faulty、imperfection、imperfectly、incomplete、incompletely、vicious

「imperfecta」

　　[★]

n.

不全症

関: failure、insufficiency

[Slootweg2007-1] Pieter J. Slootweg (2007). Dental pathology: a practical introduction. Springer Science & Business Media. pp. 19–. ISBN 978-3-540-71690-7. Retrieved 28 December 2010.

[:0-2] American Academy of Pediatric Dentistry, Guideline on Dental Management of Heritable Dental Developmental Anomalies, 2013, http://www.aapd.org/media/Policies_Guidelines/G_OHCHeritable.pdf

[3] Lagerström M, Dahl N, Nakahori Y, Nakagome Y, Bäckman B, Landegren U, Pettersson U (1991). "A deletion in the amelogenin gene (AMG) causes X-linked amelogenesis imperfecta (AIH1)". Genomics. 10 (4): 971–975. doi:10.1016/0888-7543(91)90187-j. PMID 1916828.

[4] Rajpar MH.; Harley K; Laing C; Davies RM; Dixon MJ (2001). "Mutation of the gene encoding the enamel-specific protein, enamelin, causes autosomal-dominant amelogenesis imperfecta". Hum. Mol. Genet. 10 (16): 1673–1677. doi:10.1093/hmg/10.16.1673. PMID 11487571.

[5] Kim JW, Simmer JP, Hart TC, Hart PS, Ramaswami MD, Bartlett JD, Hu JC (2005). "MMP-20 mutation in autosomal recessive pigmented hypomaturation amelogenesis imperfecta". J. Med. Genet. 42: 271–275. doi:10.1136/jmg.2004.024505. PMC 1736010. PMID 15744043.

[6] Hart PS, Hart TC, Michalec MD, Ryu OH, Simmons D, Hong S (2004). "Mutation in kallikrein 4 causes autosomal recessive hypomaturation amelogenesis imperfecta". J. Med. Genet. 41 (7): 545–549. doi:10.1136/jmg.2003.017657. PMC 1735847. PMID 15235027.

[7] Kim JW, Lee SK, Lee ZH, Park JC, Lee KE, Lee MH, Park JT, Seo BM, Hu JC, Simmer JP (2008). "FAM83H mutations in families with autosomal-dominant hypocalcified amelogenesis imperfecta". Am. J. Hum. Genet. 82: 489–494. doi:10.1016/j.ajhg.2007.09.020. PMC 2427219. PMID 18252228.

[8] El-Sayed W, Parry DA, Shore RC, Ahmed M, Jafri H, Rashid Y, Al-Bahlani S, Al Harasi S, Kirkham J, Inglehearn CF, Mighell AJ (2009). "Mutations in the beta propeller WDR72 cause autosomal-recessive hypomaturation amelogenesis imperfecta". Am. J. Hum. Genet. 85: 699–705. doi:10.1016/j.ajhg.2009.09.014. PMC 2775821. PMID 19853237.

[9] Parry DA, Brookes SJ, Logan CV, Poulter JA, El-Sayed W, Al-Bahlani S, Al Harasi S, Sayed J, Raïf M, Shore RC (2012). "Mutations in C4orf26, Encoding a Peptide with In Vitro Hydroxyapatite Crystal Nucleation and Growth Activity, Cause Amelogenesis Imperfecta". Am. J. Hum. Genet. 91: 565–571. doi:10.1016/j.ajhg.2012.07.020. PMID 22901946.

[10] Parry DA, Poulter JA, Logan CV, Brookes SJ, Jafri H, Ferguson CH, Anwari BM, Rashid Y, Zhao H, Johnson CA, Inglehearn CF, Mighell AJ (2013). "Identification of mutations in SLC24A4, encoding a potassium-dependent sodium/calcium exchanger, as a cause of amelogenesis imperfecta". Am. J. Hum. Genet. 92 (2): 307–312. doi:10.1016/j.ajhg.2013.01.003. PMID 23375655.

[11] Poulter JA, El-Sayed W, Shore RC, Kirkham J, Inglehearn CF, Mighell AJ (2013). "Whole-exome sequencing, without prior linkage, identifies a mutation in LAMB3 as a cause of dominant hypoplastic amelogenesis imperfecta". Eur. J. Hum. Genet. 22 (1): 132–5. doi:10.1038/ejhg.2013.76. PMID 23632796.

[12] Wang SK, Choi M, Richardson AS, Reid BM, Lin BP, Wang SJ, Kim JW, Simmer JP, Hu JC (2014). "ITGB6 loss-of-function mutations cause autosomal recessive amelogenesis imperfecta". Hum. Mol. Genet. 23 (8): 2157–63. doi:10.1093/hmg/ddt611. PMC 3959820. PMID 24305999.

[13] Illustrated Dental Embryology, Histology, and Anatomy, Bath-Balogh and Fehrenbach, Elsevier, 2011, page 64

v t e Developmental tooth disease/tooth abnormality (K00–K01, 520)

Quantity	Anodontia/Hypodontia Hyperdontia

Shape and size	Concrescence Fusion Gemination Dens evaginatus/Talon cusp Dens invaginatus Enamel pearl Macrodontia Microdontia Taurodontism Supernumerary roots

Formation	Dilaceration Regional odontodysplasia Turner's hypoplasia Enamel hypoplasia Ectopic enamel

Other hereditary	Amelogenesis imperfecta Dentinogenesis imperfecta Dentin dysplasia Regional odontodysplasia

Other	Dental fluorosis Tooth impaction

匿名

検索

案内

案内

amelogenesis imperfecta