Sirenomelia. Pathological features, antenatal ultrasonographic clues, and a review of current embryogenic theories.

We aimed to discuss the prenatal diagnosis and pathological features of sirenomelia, and to review current embryogenic theories. We observed two sirenomelic fetuses that were at the 19th and 16th gestational week respectively. In the former, transvaginal ultrasound revealed severe oligohydramnios and internal abortion, whereas bilateral renal agenesis, absence of a normally tapered lumbosacral spine, and a single, dysmorphic lower limb were detected in the latter. In both cases, X-rays and autoptic examination allowed categorization on the basis of the skeletal deformity. Subtotal sacrococcygeal agenesis was present in both cases. Agenesis of the urinary apparatus and external genitalia and anorectal atresia were also found. Classification of sirenomelia separately from caudal regression syndrome is still debated. Recent advances in the understanding of axial mesoderm patterning during early embryonic development suggest that sirenomelia represents the most severe end of the caudal regression spectrum. Third-trimester ultrasonographic diagnosis is usually impaired by severe oligohydramnios related to bilateral renal agenesis, whereas during the early second trimester the amount of amniotic fluid may be sufficient to allow diagnosis. Early antenatal sonographic diagnosis is important in view of the dismal prognosis, and allows for earlier, less traumatic termination of pregnancy.     

应用三维超声断层成像技术产前诊断胎儿阴茎阴囊转位

目的 分析胎儿阴茎阴囊转位在三维超声断层成像（TUI）中的图像特征,评价TUI诊断胎儿阴茎阴囊转位的价值。方法 34例可疑为阴茎阴囊转位的胎儿,胎儿孕周为24 ～ 40周,平均孕周32.0周。分别应用二维超声和三维超声TUI技术进行诊断,将两种检查技术所得到的检查结果进行比较。结果 34例胎儿中,生后或尸检证实31例为阴茎阴囊转位,应用三维TUI技术诊断胎儿阴茎阴囊转位的准确度（93.94 %）比应用二维超声诊断的准确度（66.67 %）高;两种方法对于诊断胎儿阴茎阴囊转位的差异有统计学意义（P 〈 0.05）。结论 三维TUI技术在产前诊断胎儿阴茎阴囊转位上具有较高的临床应用价值。 更多还原     

Rapid diagnosis of β-thalassaemia by mutagenically separated polymerase chain reaction (MS-PCR) and its application to prenatal diagnosis

Summary. We have developed a rapid and simple PCR-based method which is modified from the mutagenically separated polymerase chain reaction (MS-PCR) to detect the molecular defects of β-thalassaemia. We can use this technique to amplify normal and mutant alleles of the β-globin gene in the same reaction tube, using different-sized allele-specific primers. This mutagenesis separates the amplification reactions of alleles performed in the same tube, Subsequent gel electrophoresis shows at least one of the two allelic products at the same locus or at least two of the several allelic products at different loci. Therefore, in addition to simple handling, MS-PCR provides a within-assay quality control for the exclusion of false negative results. The five most common mutations of β-thalassaemia and haemoglobin E which occur in the Taiwanese population were tested, and 14 prenatal samples were checked with accurate results. This method is simple, rapid and accurate, and can be used routinely in prenatal diagnosis. The principle used here can also be applied to other genetic diseases.     

产前超声筛查胎儿畸形——附128例分析

目的:探讨超声对孕期胎儿畸形的诊断价值。方法:对孕期经超声检查的128例胎儿畸形进行分析。结果:128例胎儿畸形中产前诊断与产后完全符合122例,未能在产前超声诊断畸形儿6例(4例漏诊、2例诊断不完全符合)。结论:超声可实时观察宫内胎儿各器官发育情况;在孕期能及早发现先天性畸形,对临床有重要的诊断价值。