The absence of one umbilical artery (SUA) is the most common malformation of the umbilical cord. It may accompany other abnormalities or occur as an isolated defect. We examined 885 fetuses, terminated following the prenatal diagnosis of serious or lethal malformations between April 1977 and March 1989, for the presence of SUA. We found 62 cases of SUA. This represents an incidence of 7.01% (62/885). The most common abnormalities found in association with SUA were: (1) multiple malformations (8/11 cases, SUA incidence = 72.7%), (2) ADAM complex (7/14 cases, SUA incidence = 50.%), (3) multicystic renal dysplasia (5/20 cases, SUA incidence = 25.%), and (4) Potter sequence (5/21 cases, SUA incidence = 23.8%). These associations have not been documented previously. In 6 fetuses the Meckel syndrome was diagnosed, and SUA was present in 2 of these. Therefore, SUA may represent an additional anomaly in Meckel syndrome that has not been reported previously.

The authors discuss the diagnostic criteria of iniencephaly based on data from the literature and eleven additional, new cases. The most important differential diagnostic problems involve anencephaly with spinal retroflexion and the Klippel‐Feil syndrome. Ultrasound indicated cranio‐spinal alterations while amniotic fluid AFP estimation and exfoliative cytology substantiated abnormal closure of the neural tube, thus comprising helpful means for prenatal diagnosis of iniencephaly. The authors emphasize the need for median‐sagittal sectioning through the spinal column for accurate evaluation of vertebral abnormalities. This, together with close observation of the occiput and the foramen magnum, helps the precise diagnosis of iniencephaly and once regularly applied will most likely result in more frequent recognition of this developmental abnormality.

SUMMARY The outcome of four successive pregnancies in a woman heterozygous for X linked hydrocephalus is described. The last two were scanned by ultrasound. In one, a good prognosis was given; the fetus was male but there was no evidence of dilated cerebral ventricles. In the other, hydrocephalus was diagnosed. The absence of aqueductal stenosis in this case supports the hypothesis that in this X linked condition communicating hydrocephalus is the primary defect and aqueductal stenosis is secondary.Since the original description of X linked inheritance in congenital hydrocephalus,1 reports have nearly all confirmed that the syndrome is caused by stenosis of the aqueduct of Sylvius.2 -Until recently, prenatal sex determination followed by selective termination of pregnancy in the case of a male fetus was the only procedure available to avoid term delivery of an affected child.5 6 Nowadays, early development of hydrocephalus can be diagnosed by ultrasound as early as the mid-trimester of gestation on the basis of dilatation of the cerebral lateral ventricles.7At our Genetic Counselling Clinic we have seen six families with isolated hydrocephalus; four appeared to be transmitted through autosomal recessive inheritance and two through X linked recessive inheritance. One of the latter is the subject of this report, and the absence of aqueduct stenosis is demonstrated. Case reportsIn 1972, the proband (fig 1, 11.2), at the age of 18, delivered a hydrocephalic male infant (111.1) at 37 week's gestation, weighing 3450 g, who died during the first week of life. According to her parents one of her two brothers was also hydrocephalic (11.3). A year later she delivered a stillborn hydrocephalic male weighing 3550 g (III.2). These two deliveries took place outside our Institute and no detailed necropsies were carried out.

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Recently, Donnenfeld et a1 [1985] reported on a twin pregnancy with multiple fetal anomalies that presented as an amniotic band sequence diagnosed prenatally by ultrasound. The patient decided to continue the pregnancy, and the ultrasound diagnosis of amniotic bands and the band sequence were confirmed after birth.We have established a centralized fetal malformation screening program in Eastern Hungary [Papp et al, 19851, and between 1 July 1983 and 31 December 1984, 12,131 consecutive pregnancies were screened by maternal serum AFP estimation at the 16th gestational week and by ultrasound examination at 18 weeks (Picker LS 2000 realtime grey-scale ultrasound equipment). During this period, 95 cases of fetal malformation were detected, including one fetus with the amniotic band sequence. However, using ultrasound at 18 weeks, we detected amniotic bands, without signs of the sequence or other fetal malformation, in five other pregnancies (Figs. 1,2). These pregnancies continued to term with scanning every 4 weeks. In two of these pregnancies, the bands disappeared during the following monitoring period and were not visible in the infant at birth. In the three other pregnancies, bands persisted on scanning, and at birth were seen to involve the placenta only. All five newborn infants were free of bands and showed no malformations.We suggest that "innocent bands" may exist (Fig. 3), and one should be very careful in evaluation of amniotic bands where there are no obvious ultrasound signs of fetal malformation.Recently, this problem was also raised by Mahony et a1 [ 19851.