Prenatal diagnosis of partial trisomy 12q: clinical presentations and outcome

We present a pregnant woman with a fetus prenatally diagnosed as 46, XY,der(4) t(4;12) (q35.1; q21.2). This defect resulted from the unbalanced segregation of a paternal balanced translocation, t(4;12) (q35.1; q21.2). Prenatal ultrasound revealed borderline ventriculomegaly, a thick nuchal fold, pericardial effusion, arthrogryposis, a single umbilical artery, and micropenis. Fluorescence in situ hybridization (FISH) with whole chromosome painting probe and microarray-based comparative genomic hybridization analysis further confirmed chromosomal gain of terminal 12q. The woman had her pregnancy terminated at 20 weeks of gestational age. When compared with previously reported cases, the proband had characteristics common to the phenotypes of partial trisomy 12q, including an abnormal facial appearance and multiple anomalies. Additionally, this case had previously unreported phenotypes, such as arthrogryposis, a single umbilical artery, and a micropenis. Regarding the outcome of partial trisomy 12q, the fetuses carrying trisomies distal to 12q24 have a good chance of extended postnatal survival. In contrast, the cases with trisomies involving a larger amount of 12q likely die prenatally or within a few days after birth. Copyright © 2005 John Wiley & Sons, Ltd.     

Prenatal diagnosis of Joubert syndrome: a case report

Joubert syndrome is a rare, autosomal recessive condition, first described by Joubert in 1969. We present a case of Joubert syndrome from a consanguineous family in which, apart from the cerebellar vermis agenesis, ventriculomegaly, bilateral postaxial polydactyly of hands and right foot and micropenis, episodes of fetal breathing pattern with an increased respiratory rate were also demonstrated by prenatal ultrasound scan. At birth the infant showed an odd face and bilateral fleshy nodules of the tongue. He had an abnormal breathing pattern of alternating tachypnea and apnea. Cranial MRI showed molar tooth sign, hydrocephalus and Dandy–Walker malformation. He had nystagmus, and electroretinography showed retinal dystrophy. Copyright © 2002 John Wiley & Sons, Ltd.     

Prenatal ultrasound diagnosis of cloacal exstrophy associated with myelocystocele complex by the ‘elephant trunk–like’ image and review of the literature

A case of cloacal exstrophy (CE) was detected by ultrasound as early as 22 weeks of gestation in association with myelocystocele complex, an unusual form of occult spinal dysraphism often associated with such a disease. The ultrasonographic diagnosis was made through the detection of a wavy cord-like segment of soft tissue protruding from the anterior abdominal wall, just below the umbilical cord insertion, strongly resembling the trunk of an elephant. Our article enforces the suggestion that the ultrasound elephant trunk–like image should be added to the existing major criteria for making prenatal diagnosis of CE. Copyright © 2005 John Wiley & Sons, Ltd.     

The variation of risk estimates through pregnancy in second trimester maternal serum screening for Down syndrome

The variation of risk estimates in second trimester maternal serum screening for Down's syndrome has been shown to be considerable in quality control schemes, i.e. UKNEQAS. We studied the biological variation of risk estimates in 16 women through pregnancy. The maternal serum markers alpha-fetoprotein (AFP), human chorionic gonadotrophin (hCG), unconjugated estriol (uE3) and β-hCG were determined six times during late first to late second trimester, and the associated likelihood ratios for Down syndrome were calculated. The interpersonal variation of markers, as well as that of the likelihood ratio, was much greater than the intrapersonal variation. The average intrapersonal standard deviation (SD) of the triple test log likelihood ratio was 0.2291, corresponding to a central 95-percentile interval 0.36–2.81 of the likelihood ratio. The interpersonal SD of the log likelihood ratio was 0.5482, corresponding to a central 95-percentile interval 0.08–11.87 of the likelihood ratio. The large difference between the intra- and interpersonal variation makes it unlikely that biological variation through pregnancy is a major contributor to the variation of risk estimates obtained several times in the same pregnancy. Rather, improvements in analytical quality and laboratory management must be expected to result in reduced variation and, in consequence, better performance of screening. Copyright © 2002 John Wiley & Sons, Ltd.