常染色体显性遗传性少毛症研究进展

常染色体显性遗传性少毛症是一组较少见的临床和遗传异质性较强的疾病,表现为出生时或出生后不久即出现头皮或身体其他部位的毛发稀疏甚至完全缺失。该病既可单独发病,也可以作为其他综合征的一项临床表型。根据遗传表型的不同,该病可分为单纯性遗传性少毛症、遗传性头皮单纯性少毛症、Marie Unna型遗传性少毛症及常染色体显性遗传性羊毛状发。该文针对单独发病的常染色体显性遗传性少毛症的遗传学研究进展作一综述。     

遗传性秃发或少毛症研究进展

遗传性秃发或少毛症是皮肤科一组比较少见的疾病.根据临床类型不同其具有特征性的临床表现各异.该组疾病的遗传方式可表现为常染色体显性遗传、常染色体隐性遗传和X连锁显性或隐性遗传.在分子遗传学方面,已有多个致病基因位点和/或致病基因被确定,如8p21、6p21、18p11、16q22、18q12、3q26、1p21、Xq13、5q32等致病基因位点和HR、CDH3、CDSN、DSG4、LIPH、ATP7A等基因.     

q遗传性秃发／少毛症分子遗传学研究进展

遗传性秃发／少毛症是一组临床少见的遗传性脱发性疾病。近年确定多种遗传性秃发／少毛症的致病基因及其染色体定位,包括Marie—Unna型遗传性少毛症（U2HR,8p21．3）、常染色体显性遗传性单纯性少毛症（APCDDl,18p11．22;RPL21,13q12）、常染色体隐胜遗传性单纯性少毛症（DSG4,18q12．1;DSC3,18q21．1;LIPH,3q26—27;P2RY5,13q13—14;10q11．23—22．3;7p21．3-22-3）、常染色体隐陛遗传性羊毛状发（LIPH,3q26—27;P2RY5,13q13—14）、常染色体显性遗传性羊毛状发（KRT74,12q12—14）和毛囊性鱼鳞病一秃发一畏光综合征（MBTPS2,Xp22）。这些基因在毛囊发生和毛囊生长周期过程中具有重要的调控作用,各种致病性突变均可导致毛囊发生和生长异常,引起秃发／少毛症。     

常染色体隐性遗传性羊毛状发1例及基因突变研究

目的:分析1例羊毛状发患儿及其父母的基因突变。方法:收集羊毛状发患儿及其父母外周静脉血,提取DNA,同时收集100例非家系健康汉族人DNA作为对照。采用聚合酶链式反应(PCR)法扩增LPAR6、LIPH、KRT25、KRT7及KRT7基因所有外显子,并对其产物进行测序分析。结果:该例患儿未发现LPAR6、KRT25、KRT7及KRT基因突变,LIPH基因存在3处杂合突变。突变1为错义突变c.973CT,突变2为错义突变c.614AG,突变3为错义突变c.454GA。对患儿父母的基因分析表明突变1及突变2均来自其父亲,而突变3来自其母亲。健康对照组中均未发现该杂合突变。结论:LIPH基因的复合杂合突变c.614AG及c.454GA导致该常染色体隐性遗传羊毛状发家系的临床表型,c973CT可能为LIPH基因编码区一新的单核苷酸多态性(SNP)。     

遗传性出血毛细血管扩张症分子遗传学研究进展

遗传性出血性毛细血管扩张症(hereditary hemorrhagic telangiectasis, HHT,OMIM 187300)是常染色体显性遗传性血管发育导常的一种疾病.目前,该病的相关基因有3种,分别是ENG、ALD-1和SMAD4基因.通常由ENG突变引起HHTI型,ALK-1突变引起HHT2型,SMAD4突变引起JPHT型.对HHT进行遗传流行病学分析及其深入的分子遗传学研究有利于指导其临床诊治和预防.     

遗传性对称性色素异常症分子遗传学研究进展

遗传性对称性色素异常症是一种较为少见的常染色体显性遗传性皮肤病。近年来该病的分子遗传学研究取得了很大的进展，致病基因已确定为1q11-q21上的ADAR基因，其编码的产物为RNA特异性腺嘌呤核苷酸脱氨酶。综述该病的致病基因定位、ADAR基因的结构、基因编码的产物、功能以及基因突变与疾病表型之间的关系。     

常染色体隐性遗传性羊毛状发伴少毛症两家系基因突变分析

目的：检测常染色体隐性遗传性羊毛状发伴少毛患者家系的致病基因。方法：收集2例中国汉族常染色体隐性遗传性羊毛状发伴少毛家系患者及其父母外周血标本,应用二代皮肤靶向测序包检测血样中DNA的基因突变,Sanger测序进行家系验证,Minigene验证剪切突变致病性。结果：先证者1的LIPH基因检测到c.742C>A（p.His248Asn）和c.982+12A>G的复合杂合突变。先证者2的LIPH基因检测到c.629-1_629delinsTT和c.686delAinsGTAGAACCCAACCTGGCT的复合杂合突变。一代测序验证显示复合杂合突变分别来自母亲和父亲。LIPH c.982+12A>G和c.629-1_629delinsTT尚未报道过,Minigene验证发现,剪切突变c.982+12A>G会导致内含子滞留;剪切突变c.629-1_629delinsTT会导致外显子跳跃和外显子缺失。结论：本文报道了LIPH的两个新剪切突变,通过家系验证和Minigene验证了剪切突变的致病性,丰富了LIPH导致常染色体隐性羊毛状发伴少毛的突变谱。     

常染色体隐性遗传性少毛症7型1例并文献复习

患者女,3岁,头发稀疏3年,父母毛发正常,家族中无类似患者.查体:头发浅褐色,稀疏、细软、轻度卷曲,眉毛、睫毛及体毛未见明显异常,牙齿、指趾甲及出汗正常.皮肤镜:大部分毛囊均为单根发、中间发,少许毳毛,发干较细,颜色较淡.皮损组织病理示:纵切面可见毛囊数量减少,横切面可见大量中间发,毳毛毛囊数量增加,毛囊周围炎细胞浸润...     

遗传性泛发性色素异常症遗传学研究进展

遗传性泛发性色素异常症以常染色体显性遗传模式为主,也可表现为常染色体隐性遗传.近年来该病的分子遗传学研究取得较大进展,找到3个不同致病区域,分别为6q24.2-q25.2、12q21-q23和2q35.发现2q35上的ATP结合盒亚家族B成员6为该病的致病基因,进一步通过基因功能证实,免疫组化显示,ABCB6抗体在上皮细胞质中弥散性分布,蛋白免疫印迹显示,ABCB6在黑素细胞和角质形成细胞中有表达,斑马鱼实验证明了ATP结合盒亚家族B成员6在色素代谢方面起重要作用.目前报道,遗传性泛发性色素异常症的ABCB6基因突变位点共8个,包括1个移码突变,7个错义突变.     

单纯型遗传性大疱性表皮松解症分子遗传学研究进展

单纯型大疱性表皮松解症是一种常染色体遗传性皮肤病.已证明KRT5、KRT14、PLEC1等基因与该病的发生有密切关系.随着遗传学技术的发展,对该病的研究越来越深入,突变发生的位置与单纯型大疱性表皮松解症的临床分型及严重程度密切相关.产前诊断和检查也有了突破.     

Marie Unna hypotrichosis: an autosomal dominant hair disorder

Hereditary hypotrichosis of Marie Unna type is a rare distinctive syndrome of hair loss which is inherited with an autosomal dominant gene. We report a family with more than half affected individuals in 4 subsequent generations which supports the very strong autosomal dominant pattern of inheritance.     

Mutations in the P2RY5 gene underlie autosomal recessive hypotrichosis in 13 Pakistani families

Background  Autosomal recessive hypotrichosis is a rare genetic irreversible hair loss characterized by sparse scalp hair, sparse to absent eyebrows and eyelashes, and sparse axillary and body hair. Affected male individuals have normal beard hair.
Objectives  To search for pathogenic mutations in the human P2RY5 gene in Pakistani families with autosomal recessive hereditary hypotrichosis.
Methods  In the present report, 16 unrelated consanguineous Pakistani families having multiple affected individuals with autosomal recessive hypotrichosis were investigated. Linkage in these families was searched by genotyping microsatellite markers linked to autosomal recessive hypotrichosis loci LAH1, LAH2 and LAH3. Thirteen of the families showed linkage to the LAH3 locus on chromosome 13q14.11–q21.32. These families were then subjected to direct sequencing of the P2RY5 gene, which encodes a G protein-coupled receptor.
Results  Sequence analysis of the P2RY5 gene revealed two novel missense mutations (c.742A>T; p.N248Y and c.830C>T; p.L277P) in three families. Five previously described mutations including three missense (c.188A>T; p.D63V, c.436G>A; p.G146R, c.562A>T; p.I188F), one insertion (c.69insCATG; p.24insHfsX52) and one complex deletion (c.172–175delAACT; 177delG; p.N58–L59delinsCfsX88) were detected in the other 10 families.
Conclusions  Mutations revealed in the present study extend the body of evidence implicating the P2RY5 gene in the pathogenesis of human hereditary hair loss.     

Topical fluocinolone acetonide acetate ointment in autosomal dominant congenital hypotrichosis

Hypotrichosis present at birth occurring as an isolated defect in three members of an Afghan family and transmitted as an autosomal dominant trait, responded to topical applications of fluocinolone acetonide acetate ointment. The patients were a 9-year-old boy, his 7-year-old sister and their 30-year-old mother who since birth, had sparse, light-coloured and thin hairs on their scalp which would not grow longer than 1 cm in length. Microscopic examination revealed the hairs to be thin and fragile, but of a uniform thickness. Some of the hairs showed secondary trichorrhexis. Following topical applications of 0.1% fluocinolone ointment, the hairs became coarser and increased in length from an ayerage of 0.7 cm before treatment to 6.2 and 7.1 cm in the two children after 10 months. The mother who started the treatment later also showed improvement.     

Refinement of a locus for Marie Unna hereditary hypotrichosis to a 1.1-cM interval at 8p21.3

BACKGROUND: Marie Unna hereditary hypotrichosis (MUHH) is a rare autosomal congenital alopecia with progressive hair loss starting in early childhood and accelerating at puberty. A locus for MUHH has been mapped on chromosome 8p21 but no genes for MUHH have been identified to date. OBJECTIVES: To refine the MUHH locus to a narrow chromosome region to facilitate cloning of the gene. METHODS: We performed genotyping and linkage analysis in a multigeneration Chinese family with MUHH, using 18 high-density microsatellite markers spanning the previously mapped interval at 8p21. RESULTS: Significant evidence for linkage was observed in this region, with a maximum two-point LOD score of 3.01 (theta = 0). Haplotype analysis localized the MUHH locus within the region defined by D8S282 and D8S1839. This region overlaps by 1.1-cM with the previously reported MUHH region and represents a physical distance of about 380 kb. CONCLUSIONS: This study provides a refined map location (1.1 cM) for isolation of the gene causing MUHH. These data also indicate the existence of a common MUHH locus at 8p21.3 between affected caucasian and Chinese families.     

A novel mutation of the glomulin gene in an Italian family with autosomal dominant cutaneous glomuvenous malformations

Glomuvenous malformations (GVM) are hamartomas characterized histologically by glomus cells, which should be distinguished from glomus tumors. Familial GVM are rare, often present as multiple lesions, and exhibit familial aggregation, with autosomal dominant transmission. GVM are caused by mutations of the glomulin (GLMN) gene on chromosome 1p21-p22. Their development is thought to follow the 'two-hit' hypothesis, with a somatic mutation required in addition to the inherited germline mutation. We describe a novel GLMN mutation in an Italian family with GVM in which some members present with the less commonly observed phenotype of solitary lesions. A second somatic 'hit' mutation in GLMN was not discovered in our family. We further provide histological, immunohistochemical and electron microscopic data exhibiting the classic features of GVM. The diagnosis of GVM is critical because of distinction from venous malformations and blue rubber bleb nevus syndrome, which may demonstrate clinical similarities but require different treatment.     

Congenital hypotrichosis due to short anagen

Two children with congenital hypotrichosis are described. Both presented with persistent short, fine hair since birth. Evidence is provided that the short hair observed in these patients is due to a short anagen phase of the hair cycle, with a normal rate of hair growth. Shortening of the anagen phase of the scalp hair cycle leads to a decrease in the maximal hair length and an increase in the number of hairs in telogen, resulting in an increase in hair shedding. Scanning electron microscopy showed a widely spaced cuticular pattern, a finding typically seen in hair of thin calibre. One patient had affected family members with an apparently autosomal dominant mode of inheritance. The disorder appears to resolve spontaneously during puberty and adulthood.     

Molecular basis of hypotrichosis with juvenile macular dystrophy in two siblings

BACKGROUND: Hypotrichosis with juvenile macular dystrophy (HJMD) is a rare autosomal recessive disorder characterized by sparse and short scalp hair from birth, followed within a few years by progressive macular degeneration leading to blindness. HJMD was shown to result from mutations in CDH3 encoding P-cadherin. OBJECTIVES: In the present study, we attempted to identify the molecular basis of abnormal hair growth in two siblings of Arab Muslim origin with hypotrichosis but no visual symptoms. METHODS: Mutation analysis was performed using direct sequencing and polymerase chain reaction-restriction fragment length polymorphism analysis. RESULTS: Patients displayed sparse and short hair since birth. Significant macular degenerative pigmentary changes were noticed in the face of normal visual acuity. Despite the fact that a single CDH3 mutation had previously been described in several families of Israeli Arab Muslim origin, the two affected patients were found to be homozygous carriers of a novel nonsense mutation (Y615X) predicted to result in premature termination of P-cadherin translation. CONCLUSIONS: The present results indicate that all patients with congenital hypotrichosis should undergo thorough fundus examination, which, when revealing pigmentary macular changes, can be considered as indicative of an underlying CDH3 causative mutation.