Objective
Several studies have already shown the superiority of chromosomal microarray analysis (CMA) compared with conventional karyotyping for prenatal investigation of fetal ultrasound abnormality. This study used very high‐resolution single nucleotide polymorphism (SNP) arrays to determine the impact on detection rates of all clinical categories of copy number variations (CNVs), and address the issue of interpreting and communicating findings of uncertain or unknown clinical significance, which are to be expected at higher frequency when using very high‐resolution CMA.
Design
Prospective validation study.
Setting
Tertiary clinical genetics centre.
Population
Women referred for further investigation of fetal ultrasound anomaly.
Methods
We prospectively tested 104 prenatal samples using both conventional karyotyping and high‐resolution arrays.
Main outcome measures
The detection rates for each clinical category of CNV.
Results
Unequivocal pathogenic CNVs were found in six cases, including one with uniparental disomy (paternal UPD 14). A further four cases had a ‘likely pathogenic’ finding. Overall, CMA improved the detection of ‘pathogenic’ and ‘likely pathogenic’ abnormalities from 2.9% (3/104) to 9.6% (10/104). CNVs of ‘unknown’ clinical significance that presented interpretational difficulties beyond results from parental investigations were detected in 6.7% (7/104) of samples.
Conclusions
Increased detection sensitivity appears to be the main benefit of high‐resolution CMA. Despite this, in this cohort there was no significant benefit in terms of improving detection of small pathogenic CNVs. A potential disadvantage is the high detection rate of CNVs of ‘unknown’ clinical significance. These findings emphasise the importance of establishing an evidence‐based policy for the interpretation and reporting of CNVs, and the need to provide appropriate pre‐ and post‐test counselling.
Seventeen fetuses were diagnosed with isolated congenital talipes equinovarus (CTEV) on mid-trimester ultrasound at the Royal Women's Hospital, Melbourne, between January, 1992 and December 1995. Sixteen of the 17 cases had an amniocentesis performed and all karyotypes were normal. The remaining case was phenotypically normal, except for a clubfoot. None of the pregnancies was complicated by any of the recognized intrauterine environmental causes of CTEV. Four of the babies were delivered prematurely and all survived the neonatal period. Six (35%) infants did not have CTEV at birth, although 2 had postural varus feet. Nine of the 11 infants who did have CTEV at birth were treated within days of birth with plaster of Paris for periods of 6 to 12 weeks. Two infants required no further treatment, 5 required orthotics and 2 required surgery. The other 2 infants with CTEV at birth were treated with orthotics at 8 weeks of age. All infants were considered to have an excellent result at the 2 year follow-up. Seven (41%) of the prospective parents 1. Fellow in Obstetrical and Gynaecological Ultrasound.
This paper reviews our hospital's experience spanning 15 years and involving 811 women referred with abnormal cervical cytology in pregnancy. It supports the safety and accuracy of managing dysplasia in pregnancy with colposcopy, directed punch biopsy and deferral of treatment until the postpartum period. The histologically-proven progression in pregnancy to a higher grade of dysplasia postpartum was 7%. None of the women are known to have developed microinvasive or invasive cancer between antenatal assessment and postpartum review. Of these 811 women, 16% were lost to follow-up, 1 of whom subsequently represented 4 years later with invasive cervical cancer.
In cases of callosal anomaly suspected on ultrasound, FMRI provides greater certainty and the potential to identify significant additional anomalies. The additional information may alter or clarify prognosis and help parents to better understand the pathology, allowing for informed decisions about the pregnancy to be made. However, some cases may still be diagnosed with additional anomalies after delivery and parents should be aware of such limitations of antenatal imaging.
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