Type VII Collagen Gene Mutations (c.8569G>T and c.4879G>A) Result in the Moderately Severe Phenotype of Recessive Dystrophic Epidermolysis Bullosa in a Korean Patient

Dystrophic epidermolysis bullosa (DEB) are caused by mutations in the COL7A1 gene, which encodes type VII collagen. Even though more than 500 different COL7A1 mutations have been identified in DEB, it still remains to be under-investigated. To investigate the mutation of COL7A1 in moderately severe phenotype of recessive DEB (RDEB) in a Korean patient, the mutation detection strategy was consisted of polymerase chain reaction (PCR) amplification of genomic DNA, followed by heteroduplex analysis, nucleotide sequencing of the PCR products demonstrating altered mobility. In this study, we found that one mutation (c.8569G>T) was detected within exon 116. The mutation of c.8569G>T in exon 116 changed the GAG (Glu) to TAG, eventually resulted in premature termination of type VII collagen polypeptide. Furthermore the mother did not have the mutation c.8569G>T in exon 116. The other novel mutation (c.4879G>A) was detected within exon 51 of both patient and mother, thereby resulting in changing valine (Val) to isoleucine (Ile) in type VII collagen polypeptide. Taken together, in this study we identified compound heterozygosity for COL7A1 mutations (c.8569G>T and c.4879G>A) in moderately severe RDEB in a Korean patient. We hope that this data contribute to the expanding database on COL7A1 mutations in DEB.     

Epidermolysis bullosa simplex generalisata: Importance of immunofluorescence studies in early diagnosis

Summary An unusual case of severe generalized epidermolysis bullosa (EB) simplex is described. Its severity, oral involvement and early milia formation suggested a dystrophic form of the disease, but early immunofluorescence studies on skin biopsy material using bullous pemphigoid (BP) serum clearly showed the level of cleavage to be superficial to the dermo-epidermal junction and microscopy confirmed this. The diagnosis of EB simplex was thus quickly established allowing conservative treatment to be pursued with confidence, and preventing unnecessary exposure of the child to systemic corticoid or phenytoin therapy.     

营养不良性大疱性表皮松解症COL7A1基因诊断及产前诊断

目的 分析2个营养不良性大疱性表皮松解症(DEB)家系致病基因COL7A1基因突变位点,并在此基础上探讨COL7A1基因分析用于产前诊断的可行性.方法 应用全基因捕获新一代测序(NGS)对2013年10月和2014年4月在郑州大学第一附属医院就诊的2个DEB家系中2例先证者COL7A1基因进行全基因突变检测,获得变异序列后,针对所检出变异序列进行PCR扩增后Sanger双向测序对2个DEB家系中2例先证者及其父母和100名健康个体的COL7A1基因序列进行突变验证分析,确定致病突变后,对其中1个家系中的高危胎儿进行孕早期产前诊断.结果 共发现4种COL7A1基因突变:c.5230G ＞T (p.E1744X)、c.5932C ＞T (p.R1978X)、c.5605-10 T＞G(IVS66-10 T＞G)、c.8305-1G＞A(IVS110-1G＞A).其中p.E1744X、IVS66-10 T＞G和IVS110-1G＞A为国际首次报道的突变.家系1中先证者携带COL7A1基因p.E1744X和p.R1978X无义突变,父母分别为杂合突变携带者;家系2中先证者携带COL7A1基因IVS66-10T＞G和IVS110-1G ＞A剪接区突变,父母分别为杂合突变携带者;100名健康个体未检测到上述突变.家系1中产前诊断胎儿携带与其先证者相同的突变为受累胎儿,胎儿父母选择治疗性引产术后,取胎儿标本行基因诊断,结果与产前诊断相同.结论 COL7A1基因突变是该2个DEB家系的致病原因,NGS结合Sanger测序方法可以快速且准确地进行该病的基因诊断和产前诊断.     

CLINICAL MANAGEMENT FOR EPIDERMOLYSIS BULLOSA DYSTROPHICA

Epidermolysis bullosa (EB) consists of a group of genetic hereditary disorders in which patients frequently present fragile skin and mucosa that form blisters following minor trauma. More than 20 subtypes of EB have been recognized in the literature. Specific genetic mutations are well characterized for most the different EB subtypes and variants. The most common oral manifestations of EB are painful blisters affecting all the oral surfaces. Dental treatment for patients with EB consists of palliative therapy for its oral manifestations along with typical restorative and periodontal procedures. The aim of this article is to describe two dental clinical treatments of recessive dystrophic EB cases and their specific clinical manifestations. The psychological intervention required during the dental treatment of these patients is also presented.     

Anaesthetic management of two different modes of delivery in patients with dystrophic epidermolysis bullosa

Dystrophic epidermolysis bullosa is an inherited severe bullous condition characterised by extreme skin fragility and blistering in response to minor trauma. We present two obstetric cases with recessive dystrophic epidermolysis bullosa, one who underwent elective caesarean section, the other who delivered vaginally. The key points in the anaesthetic management of the obstetric patient with dystrophic epidermolysis bullosa include multidisciplinary preassessment, airway management strategies and the role of regional anaesthesia.     

PCR-DNA直接测序检测1例单纯型大疱性表皮松解症Weber-Cockayne亚型(WC-EBS)患者角蛋白K5基因点突变

单纯型大疱性表皮松解症（ＥＢＳ）是一组常染色体显性的遗传性疾病，研究表明本病存在角蛋白Ｋ５／Ｋ１４基因点突变。ＥＢＳ的各个亚型突变发生部位有一定差异，其中Ｗｅｂｅｒ－Ｃｏｃｋａｙｎｅ亚型（ＷＣ－ＥＢＳ）突变多位于Ｋ５／Ｋ１４的连接区Ｌ１－２。本研究设计了扩增Ｋ５基因Ｌ１－２区ＤＮＡ片段的引物，应用ＰＣＲ对－ＷＣ－ＥＢＳ家系的患者及未发病成员进行扩增。ＰＣＲ产物测序发现患者Ｋ５第３４６密码子发生了Ａ→Ｃ的碱基替换，导致色氨酸（ＴＡＴ）变成丝氨酸（ＴＣＴ），而未发病成员则未见有碱基突变。结果表明，通过ＰＣＲ结合ＤＮＡ直接测序不失为快速、准确检测基因突变的方法。此外，连接区在角蛋白结构中不如螺旋区重要，因而此区基因突变对角蛋白二聚体形成的影响不大，这与临床上ＷＣ－ＥＢＳ病情相对较轻是一致的。