5
QQ截图20171226135925
3
2
3
22
44
11
33
55
当前所在位置: 北京亲子鉴定 » 资讯中心 » 基因检测项目 » II型眼皮肤白化病

更多导航

联系我们
地址:北京市海淀区中关村南大街32号中关村科技发展大厦B座
咨询热线:010-56233341   133-66022179   
预约热线:159-0141-2183  136-8331-6786(可加微信)

II型眼皮肤白化病

浏览数量:235     作者:本站编辑     发布时间: 2017-12-25      来源:本站

2型眼皮肤白化病

 

[OCA2. 包括: 棕色OCA]

 

摘要

 

疾病特征:2型眼皮肤白化病(OCA2)的特点是皮肤和头发的色素减退以及所有白化病类型都有的典型的眼部改变,包括眼球震颤、虹膜色素减退而使其呈半透明状、视网膜色素减退而使得在眼底镜检时可见脉络膜血管、与视敏度降低相关的中央凹发育不全以及与交叉斜视、立体感降低和视觉诱发电位(VEP)改变相关的视神经交叉处指向错误。由于眼球震颤和斜视等眼部症状,OCA2患者通常在一岁内即被发现患病。童年早期视力是稳定的,而且不会出现与白化病相关的视力方面的严重改变或进一步减退。OCA2患者皮肤的色素沉着量变化范围从极少到接近正常。OCA2新生儿几乎都有有色的毛发,颜色从浅黄、金黄至棕色。发色可能随着时间推迟变深,但从童年到成年不会有显著的变化。在非洲人和美国黑人中发现的拥有淡褐色头发和皮肤的棕色OCA,属于OCA2系列的一部分。

 

诊断/检测:诊断OCA2基于临床发现。OCA2基因(以前称为P基因)是唯一已知与2型眼皮肤白化病相关的基因。对在非洲裔患者中发现的2.7-kb缺失进行检测在临床基地是可行的。临床上可对OCA2基因进行序列分析和突变筛查。

 

处理:用普通或隐形眼镜校正屈光不正可能能提高视敏度;出于美容理由可考虑对斜视采用外科手术。有帽檐的帽子常能减少恐光症。以遮蔽身体的服装和遮光剂防止日晒能避免皮肤灼伤、机械损伤和皮肤癌;需避免长时间的日晒。对皮肤癌采用和普通人一样的治疗方法。

 

遗传咨询:OCA2以常染色体隐性方式遗传。先证者的父母必定是杂合子,各携带一个突变等位基因。杂合子(携带者)是无临床症状的。从概念上来说,患者的每个同胞兄妹有25%的几率成为患者,50%的几率成为无临床表现的携带者,25%的几率成为正常人且非携带者。产前检测在一个有限制的基地是可行的。

 

 

Oculocutaneous Albinism Type 2

 

[OCA2. Includes: Brown OCA]

 

Summary

 

Disease characteristics.Oculocutaneous albinism type 2 (OCA2) is characterized by hypopigmentation of the skin and hair and the characteristic ocular changes found in all types of albinism, including nystagmus; reduced iris pigment with iris translucency; reduced retinal pigment with visualization of the choroidal blood vessels on ophthalmoscopic examination; foveal hypoplasia associated with reduction in visual acuity; and misrouting of the optic nerves at the chiasm associated with alternating strabismus, reduced stereoscopic vision, and an altered visual evoked potential (VEP). Individuals with OCA2 are usually recognized within the first year of life because of the ocular features of nystagmus and strabismus. Vision is stable after early childhood and no major change or further reduction in vision occurs related to the albinism. The amount of cutaneous pigmentation in OCA2 ranges from minimal to near-normal. Newborns with OCA2 almost always have pigmented hair, with color ranging from light yellow to blond to brown. Hair color may darken with time, but does not vary significantly from childhood to adulthood. Brown OCA, initially identified in Africans and African Americans with light brown hair and skin, is part of the spectrum of OCA2.

 

Diagnosis/testing.The diagnosis of OCA2 is based on the clinical findings. The gene OCA2 (previously called the P gene) is the only gene known to be associated with oculocutaneous albinism type 2. Testing for the 2.7-kb deletion found in individuals of African heritage is available on a clinical basis. Sequence analysis and mutation scanning of the OCA2 gene are available clinically.

 

Management.Correction of refractive error with spectacles or contact lenses may improve visual acuity; strabismus surgery can be considered for cosmetic reasons. Hats with brims often reduce photophobia. Protection from sun exposure with body-covering clothing and sunscreens prevents burning, skin damage, and skin cancer; prolonged sun exposure should be avoided. Skin cancer is treated as for the general population.

 

Genetic counseling.OCA2 is inherited in an autosomal recessive manner. The parents of a proband are obligate heterozygotes and therefore carry one mutant allele. Heterozygotes (carriers) are asymptomatic. At conception, each sib of an affected individual has a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier. Prenatal testing is available on a limited basis.


联系我们
© 2017 华科基因亲子鉴定中心
地址:北京市海淀区中关村南大街32号中关村科技发展大厦B座
咨询热线:010-56233341   133-6602-2179   
预约热线:159-0141-2183   136-8331-6786(可加微信) 
京ICP备12051704号-9  技术支持:河南恒之源网络
免责声明:本网站上所有资料,内容均由网站所有人提供,与网站制作单位无关,网站制作单位不承担任何形式的责任。