基因组时代产前诊断面临的机遇和挑战

        自20世纪70年代开始，染色体核型分析技术作为诊断胎儿染色体异常的金标准已使用多年，但该技术存在分辨率较低（5~10Mb）、培养周期长、检测通量低及有培养失败风险等局限性。随后，靶向诊断技术（FISH、QF-PCR、MLPA）的出现，大大缩短了检测时间，与染色体核型技术联合应用，可早期诊断常见的胎儿染色体异常。此外，Sanger测序作为基因变异检测的金标准，可用于明确致病的单基因疾病的产前诊断。然而，以上技术均无法实现在全基因组范围内进行快速、高分辨率地诊断胎儿致病性变异。 浏览更多请关注微信公众号及当期杂志。     

经肺泡灌洗液高通量测序诊断婴儿肺孢子菌肺炎1 例并文献复习

目的探讨肺孢子菌肺炎的病因、临床表现、病原学诊断和治疗。方法回顾分析1例肺孢子菌肺炎患儿的临床资料。结果患儿,男,2个月20天,临床表现为慢性咳嗽、气促、烦躁、低氧血症;肺部影像呈双肺弥漫性浸润改变;经支气管镜术取肺泡灌洗液进行宏基因高通量测序后证实为肺孢子菌感染。确诊后予甲氧苄胺嘧啶-磺胺甲噁唑(TMP-SMZ)治疗,临床症状基本消失,肺部 CT明显好转。结论肺泡灌洗液行宏基因高通量测序可诊断肺孢子菌肺炎。     

New generation genetic testing entering the clinic

New generation sequencing (NGS) genetic testing is a powerful diagnostic tool and is increasingly used in the clinical workup of patients, especially in unusual presentations or where a positive family history suggests heritable disease. This review addresses the NGS technologies Targeted sequencing (TS), Whole exome sequencing (WES), Whole genome sequencing (WGS), and the use of gene panels or gene lists for clinical diagnostic purposes. These methods primarily assess nucleotide sequence but can also detect copy number variants and many tandem repeat expansions, greatly simplifying diagnostic algorithms for movement disorders. Studies evaluating the efficacy of NGS in diagnosing movement disorders have reported a diagnostic yield of up to 10.1% for familial and 15.7% for early-onset PD, 11.7–37.5% for dystonia, 12.1–61.8% for ataxia/spastic paraplegia and 11.3–28% for combined movement disorders. Patient selection and stringency in the interpretation of the detected variants and genotypes affect diagnostic yield. Careful comparison of the patient's or family's disease features with the previously reported phenotype associated with the same variant or gene can avoid false-positive diagnoses, although some genes are implicated in various phenotypes. Moving from TS to WES and WGS increases the number of patients correctly diagnosed, but for many patients, a genetic cause cannot be identified today. However, new genetically defined entities are discovered at rapid pace, and genetic databases and our knowledge of genotype-phenotype correlations expand steadily. We discuss the need for clear communication of genetic results and suggest a list of aspects to consider when reporting neurogenetic disorders using NGS testing.     

Myopathy associated with homozygous PYROXD1 pathogenic variants detected by genome sequencing

Biallelic pathogenic variants in the gene PYROXD1 have recently been described to cause early-onset autosomal recessive myopathy. Myopathy associated with PYROXD1 pathogenic variants is rare and reported in only 17 individuals. Known pathogenic variants in PYROXD1 include missense, insertion and essential splice-site variants. Here we describe a consanguineous family of individuals affected with late-onset myopathy and homozygous PYROXD1 missense variants (NM_024854.5:c.464A>G [p.Asn155Ser]) expanding our understanding of the possible disease phenotypes of PYROXD1-associated myopathy.     

靶向测序诊断黑棘皮病1家系

【摘要】 报道临床症状不典型的家族性黑棘皮病1家系。先证者女，4岁，自1周岁时，颈部、腹部出现黑色斑片，近年来逐渐扩大至唇周、躯干前部。腹部皮肤全反式共聚焦显微镜检查可见乳头环下延扭曲及沟壑结构，乳头环内可见中高折光颗粒结构。先证者父亲及祖母既往有类似病史，但随着年龄增长色素沉着自发性消退，仅有局部皮纹增粗。采集先证者及父母、祖母外周血，对先证者外周血DNA行Panel靶向测序，结果显示，先证者存在FGFR3基因14号外显子c.1949A>C（p.Lys650Thr）错义突变，Sanger测序验证证实先证者及其父亲和祖母均存在此突变。诊断：家族性黑棘皮病。