Combined pituitary hormone deficiency with unique pituitary dysplasia and morning glory syndrome related to a heterozygous PROKR2 mutation

Recent reports have indicated the role of the prokineticin receptor 2 gene (PROKR2) in the etiology of congenital hypopituitarism, including septo-optic dysplasia and Kallmann syndrome. In the present study, using next-generation targeted sequencing, we identified a novel heterozygous PROKR2 variant (c.742C>T; p.R248W) in a female patient who had combined pituitary hormone deficiency (CPHD), morning glory syndrome and a severely malformed pituitary gland. No other mutation was present in 27 genes related to hypogonadotropic hypogonadism, pituitary hormone deficiency and optic nerve malformation. The substituted amino acid was located on the third intracellular loop of the PROKR2 protein, which is a G protein-coupled receptor. Computational analyses with two programs (SIFT and PolyPhen-2) showed that the substitution was deleterious to PROKR2 function. The p.R248W mutation was transmitted from the patient’s mother, who had a slightly delayed menarche. Collectively, we provide further genetic evidence linking heterozygous PROKR2 mutations and the development of CPHD.     

Ion Torrent PGMTM平台在儿童遗传性疾病诊断中应用初探

目的:在PCR产物定量混合构建文库方法的基础上,探讨Ion Torrent PGMTM平台二代测序应用于儿科常见遗传性疾病诊断的价值。方法:采集临床诊断的2例肌营养不良、1例胆汁酸合成障碍和1例甲基丙二酸血症患儿的外周血,提取基因组DNA,分别针对DMD基因、HSD3B7 基因、AMACR基因及MUT基因采用PCR反应进行编码区扩增,扩增产物定量混合制备成文库,在PGM上完成测序。使用NextGENe软件进行数据分析。同时采用Sanger测序方法,对上述基因进行全基因测序;肌营养不良病例采用多重连接探针扩增（MLPA ）进行基因外显子拷贝数变异的检测。结果:例1 肌营养不良患儿DMD基因检测到6个变异,其中c.998C>A,p.333S>X为已知致病突变位点,4个为SNP（rs228406、rs1801187、rs1801188、rs1800280）。PGM检测到1个假阳性,为6个连续的T后面插入了1个T。例2 肌营养不良患儿检测到DMD基因 g.2788933943-2790543577共5个外显子的缺失,MLPA检测结果与二代测序结果相符合。例3 胆汁酸合成障碍患儿HSD3B7 基因和AMACR基因共检测到7个变异,其中HSD3B7 基因复合杂合突变c.45-46delAG,FS;c.262G>G/C,p. 88G>RG,5个为SNP（rs9938550、rs3195676、rs10941112、rs2278008、rs2287939）。例4 甲基丙二酸血症患儿MUT基因检测到3个变异,1个为已知致病突变位点杂合突变c.728-729het-insTT,FS;2个为SNP（ rs2229384、rs8589）。PGM检测到2个假阳性。结论:基于PGMTM平台、采用PCR产物定量混合构建文库测序的方法,具有低成本、高通量、高灵敏度以及可灵活设计的特点,适合用于儿科临床常见遗传性疾病的检测。但由于二代测序技术可能带来的假阳性,对于检测到的变异需要Sanger直接测序法进一步验证。     

Whole exome sequencing identified a novel single base pair insertion mutation in the EYS gene in a six generation family with retinitis pigmentosa

Retinitis pigmentosa (RP) is a group of inherited progressive retinal dystrophies (RD) and is characterized by photoreceptor degeneration. RP is clinically and genetically heterogeneous disorder. More than 70 genes are known and, thus, identification of causative genes and mutations in known genes is challenging. This study was designed to identify the underlying genetic defect in a large extended Saudi family with multiple RP affected members. Fundus photography, Optical Coherence Tomography (OCT) and visual field perimetry were performed for affected individuals. Whole exome sequencing was used to detect the underlying genetic defect in a large family with 12 affected individuals showing autosomal recessive isolated RP. WES data analysis identified a novel insertion mutation in the EYS (eyes shut homolog) gene (c.910_911insT; p.Trp304LeufsTer8). Sanger sequencing validates the variant discovered through exome in all 12 affected individuals and showed that this mutation is segregating with RP phenotype in an autosomal recessive manner in 51 individuals of the family tested here. Our study expands the mutation spectrum of EYS gene in RP patients and extends the body of evidence that supports the importance of EYS gene in eye development.     

儿童铁粒幼红细胞贫血的临床特征及基因突变谱分析

目的 对铁粒幼红细胞贫血（SA）患儿的临床特征和基因突变谱进行分析，探讨目的基因捕获二代测序技术在SA患儿分子诊断中的临床应用价值，提高对SA的早期诊断和临床干预水平。方法 收集36例诊断为SA患儿的临床资料，采用目的基因捕获二代测序方法进行SA相关致病基因、与血红素合成及线粒体铁代谢有关的基因检测，分析基因型与临床表型的关系。结果 36例患儿中，32例为遗传性铁粒幼红细胞贫血（CSA），4例为骨髓增生异常综合征伴环形铁粒幼红细胞（MDS-RS）。共53%（19/36）患儿检测到CSA相关基因突变，其中ALAS2基因突变占47%（9/19），SLC25A38基因突变占21%（4/19），线粒体片段缺失占32%（6/19）。所有MDS-RS患儿均未检测到致病/可能致病性基因突变。89%（17/19）为已知致病突变，11%（2/19）为新变异。ALAS2基因新变异c.1153A > T （p.I385F）评级为"可能致病的"及SLC25A38基因新变异c.175C > T （p.Q59X）评级为"致病的"。结论 儿童CSA以ALAS2及SLC25A38基因突变为主，但线粒体基因片段缺失亦占有相当比例，对于婴儿期即出现的低增生性贫血，需考虑线粒体病的可能。     

Germ-line mutation of KCNQ2, p.R213W, in a Japanese family with benign familial neonatal convulsion

Background: Benign familial neonatal convulsion (BFNC) is an autosomal‐dominantly inherited epilepsy of neonates. The KCNQ2 and KCNQ3 genes have been cloned as the responsible genes for BFNC. Detection of mutations in these genes is helpful for confirmation of BFNC or differential diagnosis of convulsive disorders in the neonatal period. Methods: A Japanese family with BFNC was investigated. Two siblings were clinically diagnosed as having BFNC. KCNQ2 and KCNQ3 were screened for mutations using a combination of polymerase chain reaction and denaturing high‐performance liquid chromatography. Nucleotide substitutions were confirmed by direct sequencing. Results: In the affected siblings a C‐to‐T heterozygous substitution was detected at nucleotide 683 (c.683C>T) in KCNQ2, leading to substitution of arginine with tryptophan at amino acid position 213 (p.R213W) in the S4 voltage‐sensing domain of the KCNQ2 protein. The detected mutation may disrupt this highly conserved region among potassium channel proteins. The c.683C>T substitution in KCNQ2 was not present in the parents. KCNQ3 was also analyzed and a single nucleotide polymorphism, c.1241A>G (National Center for Biotechnology Information (NCBI), SNP ID: rs2303995), was detected in the index family. Conclusions: Two siblings with BFNC had a novel heterozygous missense mutation, p.R213W, in KCNQ2. This mutation may affect potassium gating, leading to neuronal excitability or convulsions in the patients. Furthermore, neither of the parents had the p.R213W mutation, indicating that it was a germ‐line mutation. The possibility of recurrence of such a germ‐line mutation in the next siblings should be explained during genetic counseling.     

SRD5A2基因新型复合杂合突变致类固醇5-α还原酶2型缺乏症的遗传变异分析

该文报道1例类固醇5-α还原酶2型缺乏症患儿的临床特征及SRD5A2基因突变特点。患儿男性，2月龄，生后即出现尿道下裂及阴茎短小。提取患儿及父母外周血DNA，通过高通量测序技术对患儿DNA样本进行内分泌疾病相关基因的捕获测序，并对家系DNA样本进行Sanger测序验证。结果显示患儿SRD5A2基因存在c.680G > A（p.R227Q）和c.608G > A（p.G203D）复合杂合突变，其中c.680G > A来源于其父亲，为已知致病性突变，c.608G > A来源于其母亲，为新发现的突变。该研究为患儿病因诊断及该家系的遗传咨询提供了分子依据，并扩展了SRD5A2基因突变谱。     

Permanent neonatal diabetes in siblings with novel C109Y INS mutation transmitted by an unaffected parent with somatic mosaicism

Mutations involving the insulin (INS) gene are a common cause of permanent neonatal diabetes (PND). Although INS mutations typically occur de novo and germline INS mutations transmitted to offspring by unaffected parents has been described, somatic mosaicism in a parent with an INS mutation has not been previously reported. We describe two siblings (one brother and one sister) with PND (26‐ and 19‐yr old diagnosed at 3 and 7 months old, respectively), whose parents were unaffected. We performed genetic analysis of leukocyte DNA for this family. Both patients were found to carry the novel heterozygous c.326G>A substitution in exon 3 of INS, resulting in a p.C109Y change of the insulin protein. Analyses of leukocyte DNA from the parents revealed low level mutation in the sequencing trace of the father, raising the possibility of somatic mosaicism. Real‐time polymerase chain reaction (PCR) analysis showed he had approximately 73% of the mutant allele relative to his affected son. This first report of somatic mosaicism in an unaffected parent with an INS mutation suggests that parental mosaicism may be responsible for the transmission of PND in patients with de novo INS mutations. As such, appropriate counseling for recurrent risks should be considered and we recommend that molecular genetic testing for future siblings at birth should be offered to the parents of children with INS mutation.     

Truncation and microdeletion of EVC/EVC2 with missense mutation of EFCAB7 in Ellis‐van Creveld syndrome

Ellis‐van Creveld syndrome (EvC) is a ciliopathy with cardiac anomalies, disproportionate short stature, polydactyly, dystrophic nails and oral defects. To obtain further insight into the genetics of EvC, we screened EVC/EVC2 mutations in eight Vietnamese EvC patients. All the patients had a congenital heart defect with atypical oral and/or skeletal abnormalities. One had compound heterozygous EVC2 mutations: a novel mutation c.769G > T‐p.E177X in exon 6 inherited from father and another previously reported c.2476C > T‐p.R826X mutation in exon 14 inherited from mother. The EVC2 mRNA expression level was significantly lower in the patient and her parents compared to controls. Another case had a novel heterozygous EVC mutation (c.1717C > G‐p.S572X) in exon 12, inherited from his father. Of note, the mother without any EVC mutation on Sanger sequencing showed a lower expression level of EVC mRNA compared with controls. SNP array analysis revealed that the patient and mother had a heterozygous 16.4 kb deletion in EVC. This patient also had a heterozygous novel variant in exon 9 of EFCAB7 (c.1171 T > C‐p.Y391H), inherited from his father. The atypical cardiac phenotype of this patient and the father suggested that EFCAB7 may modify the phenotype by interacting with EVC. In conclusion, we detected two novel nonsense mutations and a partial deletion of EVC/EVC2 in two Vietnamese families with EvC. Moreover, we found in one family a missense mutation of EFCAB7, a possible modifier gene in EvC and its related disorders.     

A novel <Emphasis Type="BoldItalic">WT1</Emphasis> gene mutation in a patient with Wilms’ tumor and 46, XY gonadal dysgenesis

Denys–Drash syndrome (DDS) is a rare genetic disorder featuring the triad of Wilms' tumor, early-onset renal failure, and 46, XY disorder of sex development. DDS is usually caused by heterozygous missense mutations in the zinc-finger region of the WT1 gene. The most frequent constitutional WT1 mutations in DDS patients are missense mutations in exons 8 and 9. We present a new case of variable DDS in a child who was found to have a novel heterozygous missense mutation in exon 7 (c.905G>T) and a splicing mutation in exon 6 (IVS6-1G>T).     

A novel INS mutation in a family with maturity‐onset diabetes of the young: Variable insulin secretion and putative mechanisms

Insulin gene (INS) mutations cause a rare form of maturity‐onset diabetes of the young (MODY), a heterogeneous group of autosomal dominant diabetes with at least 14 confirmed causative genes. Here, we describe a family with MODY due to a novel INS mutation, detected using massively parallel sequencing (MPS). The proband presented aged 11 years with mild diabetic ketoacidosis. She was negative for IA2 and GAD antibodies. She had a strong family history of diabetes affecting both her two siblings and her mother, none of whom had ketosis but who were considered to have type 1 diabetes and managed on insulin, and her maternal grandfather, who was managed for decades on sulfonylureas. Of note, her younger sister had insulin deficiency but an elevated fasting proinsulin:insulin ratio of 76% (ref 5%‐30%). Sanger sequencing of HNF4A, HNF1A, and HNF1B in the proband was negative. Targeted MPS using a custom‐designed amplicon panel sequenced on an Illumina MiSeq detected a heterozygous INS mutation c.277G>A (p.Glu93Lys). Sanger sequencing confirmed the variant segregated with diabetes within the family. Structural analysis of this variant suggested disruption of a critical hydrogen bond between insulin and the insulin receptor; however, the clinical picture in some individuals also suggested abnormal insulin processing and insulin deficiency. This family has a novel INS mutation and demonstrated variable insulin deficiency. MPS represents an efficient method of MODY diagnosis in families with rarer gene mutations.     

肾母细胞瘤BWR1A突变的筛查

目的：探讨新发现的印迹基因BWR1A突变与胚胎性肿瘤发生的关系。方法：采用聚合酶链式反应-单链构象多态性分析（PCR-SSCP）技术及DNA测序，对55例肾母细胞瘤进行印迹基因BWR1A突变检测，以瘤旁组织为对照。结果：发现6例肾母细胞瘤标本第9外显子有异常泳动带。DNA测序其中1例1093位G缺失，产生终止密码TGA。结论：BWR1A基因突变涉及胚胎性肿瘤发生。     

A novel AVPR2 missense mutation in a Chinese boy with severe inherited nephrogenic diabetes insipidus

Inherited nephrogenic diabetes insipidus (NDI) is characterized by renal resistance to arginine vasopressin (AVP). The most common cause is mutations in the AVP receptor 2 (AVPR2) gene at Xq28. Severe complications of NDI are rare but can occur after severe dehydration without treatment. A 7-year-old boy presented with short stature and severe intellectual disability other than polyuria and polydipsia. The karyotype was normal. Direct sequencing revealed a novel missense mutation c.506T > C (p.L169P) in AVPR2 in the patient. His mother was heterozygous for the mutation. The mutation was absent in 103 unrelated healthy males and predicted to be consistently pathogenic by several prediction methods, including Polyphen, SIFT, PMut, PhD-SNP, SNPs3D, PANTHER, and MEMPACK. Awareness of the primary signs of NDI, polyuria, and polydipsia would facilitate early diagnosis and treatment to prevent its severe complications. Also, molecular analysis will provide a rapid and definitive diagnosis and facilitate genetic counseling for family planning.     

AMN基因复合杂合变异致Imerslund-Gräsbeck综合征1例临床及基因分析

目的探讨AMN基因复合杂合变异所致Imerslund-Gr?sbeck综合征(IGS)的临床和基因变异特征。方法回顾分析1例AMN基因复合杂合变异所致IGS患儿临床资料,并复习相关文献。结果患儿,男,10岁,主要表现为面色、口唇苍白;血红蛋白84 g/L,红细胞计数2.44×1012/L,红细胞平均体积96.30 fL,平均血红蛋白量34.4 pg;血维生素B12浓度83 pg/mL。血串联质谱及尿有机酸分析提示甲基丙二酸血症。基因筛查排除原发性甲基丙二酸血症相关基因致病性变异;全外显子测序提示AMN基因存在c.527_530 del和c.651+1G>C复合杂合变异,其中c.651+1G>C为新发变异。上述变异位点未见报道,经ACMG评级,c.527_530 del为疑似致病性变异,c.651+1G>C为致病性变异。结合临床表型,患儿确诊IGS。经维生素B12肌注治疗后,患儿甲基丙二酸血症和贫血症状消失。结论血串联质谱及尿有机酸分析联合基因检测尤其是全外显子测序可提高罕见遗传代谢病的诊断。     

丙酮酸脱氢酶缺乏症PDHA1基因的一个新突变及其致病性鉴定

目的研究丙酮酸脱氢酶缺乏症发病分子遗传学机制,从基因水平诊断丙酮酸脱氢酶缺乏症,为遗传咨询和产前基因诊断提供依据。方法对临床表现及实验室检查符合丙酮酸脱氢酶缺乏症的1例患儿采用PCR法对PDHA1基因的11个外显子及外显子交界区进行扩增,并通过对扩增产物直接测序检测突变。采用生物信息学方法对新突变进行氨基酸保守型分析,预测蛋白二、三级结构,鉴定其致病性。结果先症者PDHA1基因第11外显子出现小片段重复突变,即c.1111_1158dup48bp,为新发突变。50例正常对照直接测序均未检测到c.1111_1158dup48bp突变。蛋白质二级、三级结构预测结果显示:新突变c.1111_1158dup48bp引起Ser371_Phe386的16个氨基酸重复,导致蛋白质二、三级结构发生明显变化,而正常对照无此变化。结论 PDHA1基因c.1111_1158dup48bp重复突变不是多态性变异,可能是一种新的致病性突变,导致丙酮酸脱氢酶缺乏症的发病。     

Japanese patients with sporadic Hirschsprung: mutation analysis of the receptor tyrosine kinase proto-oncogene, endothelin-B receptor, endothelin-3, glial cell line-derived neurotrophic factor and neurturin genes: a comparison with similar studies

We report on mutation analysis of five genes involved in the receptor tyrosine kinase (RET) or the endothelin-signalling pathways in 28 sporadic Japanese patients with Hirschsprung disease. Analysis of DNA obtained from peripheral blood cells revealed six mutations in the RET proto-oncogene, four of which were disease-causing mutations in exon 9 (D584G), the splice donor site of intron 10 (+2T to A), exon 11 (A654T), and exon 12 (T706A). A heterozygous A to G transition was found in 47 bases upstream from the 5′ end of exon 2 in two HD patients but was also seen in one control subject (2/28; 1/24). A silent 2307T to G transversion was observed in exon 13. Two disease-causing mutations were detected in the endothelin receptor (EDNRB) gene, in the non-coding region of exon 1 (−26 G to A) and in exon 4 (A301T); the latter mutation was a novel one. One silent mutation was observed in exon 4 (codon 277). One heterozygous T to C mutation was found in the glial cell line-derived neurotrophic factor gene in 25 bases upstream of the coding region in exon 1. No nucleotide changes were detected in either the endothelin-3 or neurturin genes. Disease-causing mutation rates in the RET proto-oncogene and the EDNRB gene were estimated at 14.3% (4/28) and 10.7% (3/28), respectively. In addition to mutations in the RET and EDNRB genes, embryonic environmental factors and/or other genetic factors appear to be involved in the development of Hirschsprung disease. Further systematic studies of genetic variation in a large series of patients and controls are necessary for elucidating the pathogenesis of this disorder. Conclusion This study provides further gene alterations as disease-causing mutations in Japanese cases of sporadic Hirschsprung disease. However, the low mutation rate of the susceptibility genes may indicate that Hirschsprung disease arises from a combination of genetic and environmental factors. Received: 18 May 1999 and in revised form 13 July 1999 and 16 August 1999 / Accepted: 16 August 1999     

CCDC39基因突变致原发性纤毛运动障碍1例及其遗传咨询和产前诊断

目的 探讨对原发性纤毛运动障碍(PCD)患儿进行基因检测对指导优生优育的意义。 方法 对1例临床诊断Kartagener综合征并随访4年的患儿进行家系全外显子组测序（WES）,经高通量测序数据分析及临床诊断流程确定致病基因突变,根据基因诊断结果行针对性遗传咨询后对患儿母亲第2胎行羊水穿刺,分离羊水脱落细胞,提取基因组DNA并PCR 扩增羊水脱落细胞相应基因突变所在外显子,行直接Sanger测序。 结果 临床随访发现患儿肺功能较诊断时明显下降,胸部CT支气管扩张较前加重。WES患儿中检测到CCDC39基因c.1819A>A/T, p.K607X无义突变和c.2447_2448het_delCA, p.T816Kfs*3移码突变,2个突变均为未报道的新突变,均经功能预测工具MutationTaster预测为致病突变,分析父母突变来源确定为复合杂合突变。同时结合患儿支气管黏膜活检电镜特征性的纤毛结构异常,认定该复合杂合突变为患儿的致病突变。患儿母亲第2 胎羊水细胞CCDC39基因2个突变位点所在外显子的Sanger测序结果显示,胎儿携带母亲来源的移码突变,无父亲的无义突变,为单杂合突变携带者。 结论 采用WES检测有助于明确PCD患儿的遗传病因,在此基础上对患儿家庭行遗传咨询和产前基因诊断,可以指导优生优育。     

儿童EBV阳性噬血细胞综合征的遗传分析及其与Th1/Th2细胞因子的关系

目的 探讨遗传变异对EBV阳性噬血细胞综合征（HLH）患儿预后的影响及其与细胞因子的关系。方法 选取81例EBV阳性且已进行相关基因测序的HLH患儿，根据有无基因突变分为无突变组（n=35）和突变组（n=46），再根据基因突变方式分为单杂合突变（SHM）亚组、双杂合突变（DHM）亚组和纯合或复合杂合突变（H-CHM）亚组。测定各组患儿血清细胞因子水平，分析其与HLH基因突变的关系。结果 UNC13D基因突变出现频率最高（13/46，28%）。STXBP2 c.575G > A （p.R192H）和UNC13D c.604C > A （p.L202M）基因突变首次被报道，均判定为“可能致病的”。突变组TNF-α水平高于无突变组，IFN-γ水平低于无突变组（P < 0.05）。DHM亚组IL-4水平高于无突变组，H-CHM亚组IL-4水平低于DHM组（P < 0.0083）。H-CHM亚组的1年总生存率（39%±15%）低于无突变组、SHM亚组和DHM亚组（分别为85%±6%、86%±7%和91%±9%，P=0.001）。结论 具有基因突变的HLH患儿IFN-γ水平显著降低；H-CHM患儿的预后较差，而其他突变对其预后影响不显著，这可能有助于医生进行临床决策。     

Fibrodysplasia Ossificans Progressiva: Three Indian Patients with Mutation in the ACVR1 Gene

Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disorder characterized by ectopic bone formation involving the connective tissues leading to severe skeletal manifestations. The genetic defect in this disorder has not been characterized in Indian patients till date. The authors report three cases of FOP along with the molecular defects identified in them. Exon 4 of the ACVR1 gene was amplified and analysed by sequencing. All three cases revealed common heterozygous mutation i.e., c.617(G>A). Identification of this mutation would lead to decrease in misdiagnosis and subsequent iatrogenic harm caused to these children by unnecessary surgical procedures. Also, mutation detection would provide an opportunity for prenatal diagnosis.