儿童肾病综合征致病基因筛查策略的探讨

目的 通过儿童散发性肾病综合征（NS）致病基因及其突变特点,探讨儿童NS致病基因的筛查策略。方法 收集复旦大学附属儿科医院肾脏风湿科2011年1月1日至2013年12月31日的所有住院NS患儿的临床资料,依据发病年龄分为先天性NS（3月龄内）、婴儿型NS（～12月龄）、儿童早发型NS（～5岁）和儿童迟发型NS（～14岁）;对儿童早发型和迟发型NS再依据对糖皮质激素（GC）治疗反应分为GC敏感（SSNS）和GC耐药（SRNS）,SRNS又分为初发型和迟发型SRNS。先天性NS行NPHS1、NPHS2、PLCE1、LAMB2、LMX1B、COQ2基因所有外显子和WT1基因8、9外显子直接测序;婴儿型NS行NPHS1、NPHS2、PLCE1基因所有外显子和WT1基因8、9外显子直接测序;儿童早发型和迟发型NS行NPHS2基因所有外显子和WT1基因8、9外显子直接测序,以及NPHS1等8个基因42个常见突变位点的SnapShot分析。结果 238例NS患儿进入本文分析,男139例。①8/10例（80％）先天性NS患儿检出NPHS1基因致病性突变;②12例婴儿型NS患儿检出3例WT1（25.0%）、2例NPHS2（16.7%）和1例NPHS1（8.3%）基因突变;③8/132例（6.1％）早发型NS患儿检出基因突变,均属于初发型SRNS（8/32,25.0%）,其中WT1 3例（9.4％）、NPHS2 2例（6.3%）、NPHS1 2例（6.3%)和INF2 1例（3.1%),19例迟发型SRNS和81例SSNS患儿均未检出相关基因突变;④84例儿童迟发型NS中未检出基因致病性突变。结论 先天性NS、婴儿型NS和儿童早发型NS中的初发型SRNS患儿应是临床基因筛查的对象。NPHS1是本文先天性NS患儿的主要致病基因,推荐在先天性NS患儿行NPHS1基因检测。NPHS1、NPHS2和WT1基因突变频率在婴儿型NS和儿童早发型NS中的初发型SRNS患儿中较高,推荐这些人群中优先选择这3个基因作为目标基因进行筛查。不推荐常规在SSNS和迟发型SRNS患儿中行基因检测。     

散发性激素耐药型肾病综合征患儿30例足细胞基因突变分析

目的分析散发性激素耐药型肾病综合征(SRNS)儿童足细胞基因突变及其特点。方法研究对象为30例散发性SRNS患儿和50例尿检正常的健康志愿者。采用PCR扩增NPHS1、NPHS2和CD2AP基因全部外显子及其周围的部分内含子,WT1基因外显子8和9及其周围的部分内含子;应用DNA序列直接测定法对其PCR产物进行测序。结果在10例应用激素和免疫抑制剂治疗肾病无缓解的SRNS患儿中,发现1例携带WT1基因杂合突变——1180C>T(R394W),1例携带NPHS1基因复合杂合突变——2677A>G(T893A)和*142T>C,1例携带CD2AP基因杂合突变IVS13-137G>A。在20例应用激素或免疫抑制剂治疗肾病缓解的SRNS患儿中,发现4例患儿携带NPHS1基因单杂合突变——928G>A、IVS8+30C>T、IVS21+14G>A和IVS25-23C>T,1例患儿携带CD2AP基因单杂合突变(IVS7-135G>A)。结论对激素和免疫抑制剂均耐药的SRNS患儿需进行足细胞基因突变分析。     

中国南方汉族人家族性激素耐药型肾病综合征家系NPHS2基因突变

目的 分析中国南方汉族人家族性激素耐药型肾病综合征(SRNS)家系NPHS2基因突变及其特点.方法 研究对象为A、B、C 3个南方汉族人SRNS家系先证者及其姐和父母,50例尿检正常的南方汉族成年人作为对照人群.取所有研究对象外周静脉血3 ml,提取基因组DNA,PCR扩增NPHS2全部8个外显子及其周围的部分内含子和启动子全长序列,对PCR产物直接进行DNA序列测定.结果 对3个南方汉族人SRNS家系先证者NPHS2全部8个外显子及其周围的部分内含子进行突变分析,未发现NPHS2突变,仅在外显子8上检测到1个NPHS2基因多态性(954T＞C).在3个家系的先证者及其姐和父母的NPHS2启动子上检测到6个变异:-1715A＞G、-1709G＞A、-1000A＞T、-670C＞T、-116C＞T和-51G＞T.其中5个变异(-1709G＞A、-1000A＞T、-670C＞T、-116C＞T和-51G＞T)在100条正常染色体中也有检出,它们在SRNS患者中的等位基因频率分别与在对照人群中的等位基因频率比较差异均无统计学意义(P＞0.05);另1个变异(-1715A＞G)在家系C的先证者及其母亲(尿检正常)中检出,为杂合变异,而在100条正常染色体中未发现.-1000A＞T为新发现的NPHS2基因多态性,-1715A＞G为新发现的NPHS2变异.结论 NPHS2基因突变不是本研究3个南方汉族人家族性SRNS家系的主要致病原因.     

Broad and unexpected phenotypic expression in Greek children with steroid-resistant nephrotic syndrome due to mutations in the Wilms’ tumor 1 (<Emphasis Type="Italic">WT1</Emphasis>) gene

Mutations in the Wilms’ tumor suppressor gene 1 (WT1), most commonly within exons 8 or 9 or intron 9, are found in cases with the overlapping conditions of Denys–Drash and Frasier syndromes, as well as in patients with steroid-resistant nephrotic syndrome (SRNS). This study investigated the presence of WT1 gene mutations in cases with childhood SRNS, along with an evaluation of their clinical outcome. Twenty-seven Greek children with sporadic (19 cases) and familial (8 cases) SRNS were tested. Four phenotypically female patients with sporadic SRNS were found to carry de novo WT1 mutations, including two cases with p.R394W, and one case each with p.R366H, or n.1228+5G>A. Karyotype analysis found 46XX in three cases, but 46XY in one. No phenotype–genotype correlations were apparent in the WT1 gene positive cases since their clinical presentation varied broadly. Interestingly, one patient with a pathological WT1 nucleotide variation responded fully to combined therapy with cyclosporine A and corticosteroids. This study further illustrates that investigation of WT1 gene mutations is clinically useful to support definitive diagnosis in children presenting with SRNS in order to direct the most appropriate clinical management.     

<Emphasis Type="Italic">NPHS2</Emphasis> mutations in Indian children with sporadic early steroid resistant nephrotic syndrome

We examined the frequency and spectrum of podocin NPHS2 mutations in Indian children with sporadic steroid resistant nephrotic syndrome (SRNS). Of 25 children screened, only one (4%) had a pathogenic mutation resulting in a stop codon. The allele and genotype frequencies of the four known single nucleotide polymorphisms detected in the cohort were similar to that of controls. This finding emphasizes the need to screen for mutations in other genes involved in the pathogenesis of SRNS.     

中国南方汉族人3个家族性激素耐药型肾病综合征家系CD2AP和NPHS1基因突变分析

目的 分析中国南方汉族人家族性激素耐药型肾病综合征(SRNS)家系CD2AP和NPHS1基因突变及其特点.方法 研究对象为A、B、C 3个南方汉族SRNS家系先证者及其父母,A、B 2个家系先证者的姐姐和50例尿检正常的南方汉族成年人.取所有研究对象外周静脉血,提取基因组DNA,PCR方法扩增CD2AP基因全部18个外显子和NPHS1基因全部29个外显子及其周围的部分内含子,对PCR产物直接进行DNA序列测定.结果 在3个SRNS家系先证者未检测出CD2AP基因致病突变.在B家系的先证者检测出NPHS1基因2398C＞T(R800C)杂合突变,先证者父亲亦携带此杂合突变,但先证者母亲及姐姐未发现该突变.在50例对照人群中未发现2398C＞T突变.此外,在3个先证者及50例对照人群还检测出9种已报道的CD2AP基因多态性--IVS4-25G＞A、IVS8-95G＞A、IVS10+36C＞A、IVS10-153A＞T、IVS10-110A＞G、IVS11+82T＞C、1204C＞T、IVS16+24G＞A、IVS17-66T＞C和4种已报道的NPHS1基因多态性--349G＞A、IVS24+36C＞T、3315G＞A和IVS27+45C＞T.结论 在1个中国南方汉族SRNS家系先证者检测出NPHS1基因突变--2398C＞T,证实中国南方汉族人家族性SRNS儿童存在NPHS1基因突变,提示对其需进行NPHS1基因突变分析.     

<Emphasis Type="Italic">NPHS2</Emphasis> mutations

Objective  To uncover the frequency and the spectrum of NPHS2 mutations in Egyptian children with non familial steroid-resistant nephrotic syndrome (SRNS). Methods  Sixteen patients were screened by PCR-single-strand conformation polymorphism analysis of NPHS2 gene followed by direct sequencing. Results   NPHS2 mutations were evident in four patients (25%) who were bearing four novel mutations including two frame shift mutations (R238fs and P45fs) and two missense mutations (I136L and F216Y). There were no phenotypic or histological characteristics of patients bearing NPHS2 mutations, apart from the earlier onset of the disease, compared to those who were not bearing mutations. Conclusion   NPHS2 mutations are prevalent in Egyptian children with non-familial SRNS and this may in part explain the less favorable prognosis reported in these patients.     

NPHS1基因Fin-minor突变致中国先天性肾病综合征2例报道并文献复习

目的总结2例先天性肾病综合征芬兰型NPHS1基因Fin-minor突变患儿临床资料,提高对该病的认识。方法报道2例先天性肾病综合征患儿的临床特点。对可能致病基因NPHS1、NPHS2、PLCε1、LAMB2、COQ2和LMX1B外显子和WT1基因第8、9外显子,以及外显子相邻附近区域进行直接测序。对该家系相关成员进行NPHS1基因外显子及附近调控区域直接测序,分析突变位点,并文献综述。 结果2例患儿均于出生后1个月内起病,临床表现为肾病综合征。血清病原学检查均为阴性。家系调查未发现家族中有类似疾病的成员。NPHS1、NPHS2、PLCε1、LAMB2、COQ2、LMX1B和WT1基因分析发现,2例患儿存在双NPHS1基因杂合突变,未发现其他基因有致病性突变。1例患儿为NPHS1基因的p.R1109X（c. 3325C>T ,Fin-minor）和IVS26DS-2A>T杂合突变,IVS26DS-2A>T剪切突变为首次报道,其父亲携带IVS26DS-2A>T,其母亲携带p.R1109X。1例患儿为NPHS1基因的p.R1109X （c. 3325C>T ）和p.A1160X （c.3478C>T）杂合突变,其母亲携带p.R1109X突变,未发现p.A1160X突变,其父亲拒绝行NPHS1基因分析。以上发现的突变在100例正常人群中未发现。 结论中国先天性肾病综合征儿童不仅有NPHS1基因突变,而且有经典的Fin-minor突变,为国内首报。本研究新发现的IVS26DS-2A>T剪切突变丰富了NPHS1基因突变谱。     

中国汉族儿童散发性激素耐药型肾病综合征CD2AP基因突变分析

目的分析中国汉族散发性激素耐药型肾病综合征(SRNS)患儿CD2AP基因突变及其特点。方法40例中国汉族散发性SRNS患儿,以及50例尿检正常的汉族成年人,取外周静脉血3 ml,提取基因组DNA,应用聚合酶链反应(PCR)方法扩增CD2AP基因全部18个外显子及其周围的部分内含子,进行直接DNA序列测定。应用神经网络程序对CD2AP基因内含子突变进行隐蔽性剪接位点预测。结果在40例散发性SRNS患儿中检测出11种CD2AP基因多态性,并在3例散发性SRNS患儿中检测出3种在正常对照人群中未发现的CD2AP基因变异,IVS7-135G>A、1083T>C和IVS13-137G>A。神经网络程序分析结果结合临床表型提示,IVS7-135G>A突变为非致病突变、1083T>C和IVS13-137G>A突变的致病性不明确。结论中国汉族散发性SRNS患儿存在CD2AP基因突变,今后尚需对CD2AP基因突变与SRNS患儿临床表型的关联性进行详尽研究。     

激素耐药型肾病综合征单卵孪生姐妹WT1基因突变

目的分析1个汉族激素耐药型肾病综合征(SRNS)家系WT1基因突变及其特点。方法研究对象为1个汉族SRNS家系先证者及其单卵孪生姐姐、父母和大姐;健康对照人群为50例尿检正常的汉族成年人。取所有研究对象外周静脉血3 mL,提取基因组DNA,PCR扩增WT1基因全部10个外显子及其周围的部分内含子序列,对PCR产物直接进行DNA序列测定。结果先证者患儿临床表型为不完全型Denys-Drash综合征,其孪生姐姐临床表型为孤立性SRNS。在该对单卵孪生姐妹中均检测到WT1基因1180C>T(R394W)杂合突变,在先证者父母及其大姐和50例健康对照人群未检测到该突变;此外,还在对该孪生姐妹检测到3个相同的WT1基因多态性——126C>T、903A>G和IVS7-32C>A。结论本研究在1个汉族SRNS家系临床表型不同的单卵孪生姐妹中发现了相同的WT1基因R394W杂合突变。     

NPHS1 and NPHS2 gene mutations in Chinese children with sporadic nephrotic syndrome

Recent discoveries indicate that the molecules in glomerular podocytes and slit diaphragms may play an important role in the development of proteinuria and nephrotic syndrome. Mutational analyses of NPHS1 and NPHS2 were performed to verify this hypothesis in sporadic nephrotic syndrome (NS) patients. Clinical characteristics and DNA samples were collected from 38 Chinese children with sporadic steroid-sensitive NS, 22 with steroid-resistant NS and 30 controls. Direct sequencing was performed after PCR amplification of all 29 and 8 exons of the NPHS1 and NPHS2 genes, respectively. In NPHS1, 4 patients had heterozygous missense mutations leading to amino acid substitutions (R800C, Q453R). Furthermore, 3 known single nucleotide polymorphism (SNP) were found (T741T, V763V, S1105S). In NPHS2, 3 patients had novel heterozygous allelic variants leading to amino acid substitutions (S206I, E188D), while 1 patient was found to carry a novel nonsense mutation leading to a truncated protein product (Glu237STOP). Two known polymorphisms were also found (A318A, L346L). The results demonstrate that NPHS1 and NPHS2 mutations are also present in Chinese sporadic NS patients, suggesting that genetic changes of nephrin and podocin may play pathogenetic roles in some patients with sporadic steroid resistant NS.     

中国人先天性肾病综合征NPHS1基因突变

目的分析并确定一个中国先天性肾病综合征（CNS）家系NPHSl基因突变及特征。方法对先证者及其家系成员采用聚合酶链反应（PCR）和DNA直接测序方法进行NPHSl基因突变检测,确定基因突变的位点。同时应用限制性内切酶酶切分析的方法,分析先证者及其家系成员和对照人群的基因组DNA,确定突变特征。结果在本家系的先证者发现同时存在NPHS1的G928A（D310N）、1893～1900del8（CGAAACCG）和G2869C（V957L）的3个杂合突变。具有相同表型的姐姐（Ⅲ：11）与先证者的测序结果完全一致,而在表型正常的先证者的同父异母的大姐及对照样本均未发现这些突变。患儿母亲尿检正常,基因检测显示仅有第8外显子G928A突变;患儿父亲尿检也正常,基因检测显示仅存在第14外显子的1893～1900del 8和第21外显子的G2869C突变,没有第8外显子G928A突变。同时还在先证者发现了4种碱基变异：E117K（rs3814995）、S1105S（rs2071327）、IVS27＋45c〉t和IVS8＋68a〉g,经比对前3种均为单核苷酸多态性,位于内含子内的变异（IVS8＋68a〉g）意义有待进一步研究。结论首次发现中国人CNS存在NPHS1基因突变,并证实致病突变为国际首次报道的3个杂合突变。     

一个中国汉族人家族性激素耐药型肾病综合征家系NPHS2基因新突变

目的　分析中国汉族人家族性激素耐药型肾病综合征 (SRNS)家系NPHS2基因及突变特点。方法　研究对象为一个中国汉族人家族性SRNS家系中的先证者及其兄和父母 ,对照人群为 5 3例尿检正常成年人。取肾组织做常规光镜检查和 podocin、nephrin、α actinin、WT1表达的检查。提取外周血白细胞基因组DNA ,PCR扩增NPHS2基因 8个外显子 ;应用变性高效液相色谱(DHPLC)分析PCR产物 ,对DHPLC洗脱曲线异常者进行DNA序列测定。结果　先证者及其兄肾脏病理示 :局灶节段性肾小球硬化。先证者肾组织 podocin重组蛋白P35染色弱阳性 ,P2 1染色阴性 ;nephrin、α actinin和WT1染色的范围、定位、分布和荧光强度与对照组无差异。DHPLC示先证者及其父母洗脱曲线异常 ;DNA测序证实先证者为 4 6 7_4 6 8insT与 5 0 3G >A复合杂合突变 ,其父为 5 0 3G >A杂合突变 ,其母为 4 6 7_4 6 8insT杂合突变。结论　首次发现了一中国汉族人家族性SRNS家系中NPHS2基因突变——— 4 6 7_4 6 8insT与 5 0 3G >A复合杂合突变 ,且 5 0 3G >A突变为新发现的突变 ;同时还发现该复合杂合突变引起肾组织中抗 podocin重组蛋白P35的染色明显减弱 ,抗 podocin重组蛋白P2 1的染色阴性。     

Monogene Ursachen des nephrotischen Syndroms

Steroid-resistant nephrotic syndrome (SRNS) represents a frequent cause of end-stage renal disease in children. Renal histology shows focal segmental glomerulosclerosis in about 80% of cases. Recently, it became apparent that up to 28% of all cases of childhood nephrotic syndrome are caused by recessive mutations of podocin (NPHS2). Additional monogenic causes are mutations of nephrin (NPHS1), WT1, PLCE1, or LAMB2. The related gene products are expressed in the glomerular podocyte and are essential for development and maintenance of the glomerular filtration barrier. These genetic insights have led to a better understanding of the pathogenesis of SRNS and will allow for unequivocal molecular genetic diagnostics and for stratification in therapeutic studies.     

儿童肾母细胞瘤WT1基因突变四例报道

目的 研究儿童肾母细胞瘤患者WT1基因的突变类型及突变频率.方法应用聚合酶链反应(PCR)扩增出54例儿童肾母细胞瘤患者WT1基因全部10个外显子及其相邻内含子序列,经纯化后进行PCR产物直接测序.结果 4例患者WT1基因分别存在3个杂合无义突变及1个纯合错义突变.例1患者WT1基因7号外显子第1006位碱基A→T杂合突变,造成第336号氨基酸由赖氨酸转变为终止密码子,即K336X.例2患者WT1基因9号外显子第1168位碱基c→T杂合突变,造成第390号氨基酸由精氨酸转变为终止密码子,即R390X.例3患者WT1基因6号外显子第814位碱基G→T杂合突变,造成第272号氨基酸由谷氨酸转变为终止密码子,即E272X.例4患者WT1基因10号外显子第1228位碱基A→G纯合突变,造成第410号氨基酸由丝氨酸转变为甘氨酸,即S410G.结论 散发的中国儿童肾母细胞瘤患者WT1基因外显子突变的发生率与国外报道相近,检测到的4例突变患者中3例为无义突变、1例为错义突变.     

激素耐药性肾病伴泌尿生殖器异常患儿的临床特点及WT1基因分析

目的 分析激素耐药性肾病伴泌尿生殖器异常患儿的临床特点、WT1基因及足细胞分子表达,提高对WT1基因突变在该类疾病的重要致病作用的认识.方法 收集3例激素耐药性肾病伴有或怀疑有泌尿生殖器异常的患儿.采用PCR及RT-PCR的方法分析WT1基因及+KTS(赖氨酸-苏氨酸-丝氨酸)/-KTS比例;采用间接免疫荧光及免疫组化的方法进行足细胞分子(nephrin,pedocin,α-actinin4,WT1及CD2AP)表达.结果 3例患儿发病年龄分别为6个月、1岁及10岁;2例为男性伴泌尿外生殖器异常,1例为男性假两性畸形;临床均表现激素耐药肾病,2例肾脏病理为局灶节段性肾小球硬化.2例检测到删突变,即WT1 IVS 9+5 G＞A和WT1外显子9 1186 G＞A杂合突变.足细胞分子在WT1突变肾组织表达发生改变;1例无WT1表达,1例WT1在足细胞细胞核内的分布与正常对照不同.结论 对于激素耐药性肾病的女性患者或伴有泌尿生殖器异常的男性患者应行染色体核型和WT1基因分析.WT1突变除可能引起+KTS/-KTS比例异常,还伴有足细胞分子表达异常,从而导致蛋白尿的形成和(或)发展.     

WT1 gene analysis in sporadic early-onset and bilateral wilms tumor patients without associated abnormalities

The WT1 gene is responsible for two different genetic conditions characterized by genitourinary anomalies and susceptibility to Wilms tumor (WT): the WAGR syndrome and the Denys-Drash syndrome. Although only rarely, WT1 constitutional mutations have been reported also in WT patients without congenital defects. Due to the high survival rates that characterize the disease, these individuals must be identified and counseled in relation to their risk to transmit a cancer-predisposing genetic lesion to their offspring. Recently, tumor bilaterality and early age of onset have been suggested to be risk factors for carrying germline WT1 mutations. The authors investigated 20 patients with sporadic WT, without evidence of congenital abnormalities, diagnosed before 2 years of age and/or with bilateral presentation, for the occurrence of WT1 mutations. Southern blot analyses identified homozygous whole-gene or intragenic deletions at the tumor level in three cases. However, none of the identified alterations was found to be present at the germline level. In addition, no mutation in the coding exons and flanking sequences of WT1 was detected in the remaining 17 cases. These results suggest that early age of diagnosis and bilaterality are not by themselves efficient predictors of germline WT1 alterations in WT patients without associated abnormalities.     

糖原累积病Ib型患儿基因突变分析与临床研究

目的：糖原累积病Ib型（GSDIb）是由于SLC37A4基因突变引起葡萄糖-6-磷酸转移酶（G6PT）活性缺陷所致,该病患者大部分有反复感染及炎症性肠病的发生,预后较差。SLC37A4基因的检测对GSDIb患者的诊断、分型、预测患者的预后尤为重要。本文旨在研究糖原累积病Ib型患儿SLC37A4基因突变的情况,探讨基因型与临床表型的关系。方法：应用聚合酶链反应直接测序的方法,对拟诊GSDIb型的28例患儿行SLC37A4基因外显子及其相邻区域的突变筛查。结果：7例患儿检测到SLC37A4基因突变,检出率为25% (7/28例),包括错义突变：p.Gly149Glu（9/13,69%）、p.Gly115Arg（1/13,8%）、p.Pro191Leu（1/13,8%）;移码突变：c.959-960 insT（1/13,8%）;剪接突变：c.870+5G>A（1/13,8%）。结论：c.959-960 insT为新突变,p.Gly149Glu为本研究最常见的突变,p.Gly149Glu突变可能与患儿的严重感染相关。     

中国汉族家族性激素耐药型肾病综合征家系MYO1E基因突变分析

目的 MYO1E基因突变可导致常染色体隐性遗传型激素耐药型肾病综合征（SRNS）,该研究旨在分析中国汉族家族性SRNS家系MYO1E基因突变及其特点。方法 2005~2010年期间共收集到4个中国汉族家族性SRNS家系,共9例肾脏病患者,选取其中4例先证者为研究对象,对照人群为59例尿检正常的健康志愿者。取所有研究对象外周静脉血3 mL,提取基因组DNA;PCR扩增MYO1E基因全部28个外显子及其周围的部分内含子序列;应用DNA直接测序法进行MYO1E基因突变分析。结果 在4个中国汉族家族性SRNS家系的先证者中共检出25个MYO1E基因变异;根据对美国国立生物技术信息中心（NCBI）的单核苷酸多态性（SNP）数据库的检索,其中1个MYO1E基因杂合变异（IVS21-85G>A）首次在该研究的1个先证者中被检出,且该变异在59例正常对照人群中未检出,表明它是MYO1E基因突变;另24个变异在NCBI的SNP数据库中已公布,均为MYO1E基因多态性。生物信息学分析提示IVS21-85G>A突变不导致MYO1E基因剪切位点改变,为非致病性突变。结论 MYO1E基因突变不是该研究中国汉族SRNS家系的主要致病原因。     

Fanconi anemia gene mutations are not involved in sporadic Wilms tumor

Bi‐allelic germline mutations of the Fanconi anemia (FA) genes, PALB2/FANCN and BRCA2/FANCD1, have been reported in a few Wilms tumor (WT) patients with an atypical FA phenotype. Therefore, we screened a random cohort of 47 Dutch WT cases for germline mutations in these two FA‐genes by DNA sequencing and Multiplex Ligation‐dependent Probe Amplification (MLPA). Although several cases appeared to carry missense variants, no bi‐allelic pathogenic mutations were identified, indicating that bi‐allelic mutations in these FA‐genes do not contribute significantly to the occurrence of WT. Pediatr Blood Cancer. 2010;55:742–744. © 2010 Wiley‐Liss, Inc.