Suivi à long terme des enfants avec clarté nucale augmentée et caryotype normal

Neurodevelopmental outcome at 2 years of corrected age in fetuses with increased nuchal translucency thickness and normal karyotype compared with matched controls

OBJECTIVES

Increased nuchal translucency (NT) thickness is an antenatal marker of aneuploidy or malformation that can lead to termination of pregnancy. This study assessed the long-term neurodevelopmental prognosis of infants who had isolated increased NT in utero.

METHODS

This was a prospective cohort study of infants with a NT thickness > 95^th percentile in the first trimester, but with a normal karyotype and no major anomalies, and controls with normal NT matched for birth weight, Apgar score, place of birth, parity and gestational age at birth. At 2 years of corrected age, all infants underwent the psychometric Brunet-Lézine test to evaluate their developmental quotient (DQ), overall (global) and specifically for the areas of posture, language, coordination and sociability.

RESULTS

A total of 203 chromosomally normal infants were included in the increased-NT group and 208 in the control group. The mean global DQ was significantly lower in the increased-NT group than in the control group (108.6 ± 9.7 vs 112.8 ± 8.3; P < 0.0001), but it was within the normal range expected for that age in both groups. Similarly, the mean DQs for coordination, sociability and language, but not for posture, were significantly lower in infants with increased NT than in controls. Only one case with increased NT had a DQ < 70 (defined as severe neurodevelopmental impairment), compared with none in the control group. The difference between the two groups remained significant for a NT threshold ≥ 99^th percentile and when the data were adjusted for NT thickness, the infant's sex and the mother's educational level. In the increased-NT group, NT thickness was < 3.5 mm in over half (56%) of the infants, between 3.5 mm and 5 mm in 33% and > 5 mm in 11%, with a mean global DQ of 108.4, 110.1 and 109.7, respectively.

CONCLUSIONS

Infants who had isolated increased fetal NT in the first trimester had a significantly lower, but normal, DQ at a corrected age of 2 years, when compared with controls. The findings were independent of the infant's sex, fetal NT thickness and the mother's educational level. © 2020 Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Pregnancy outcome and long-term follow-up of fetuses with isolated increased NT: a retrospective cohort study

OBJECTIVE

To assess the prevalence of associated findings, diagnosed either prior to or after birth, among fetuses with increased nuchal translucency (NT) and normal karyotype and to investigate the prevalence of children under therapy at school age, among cases confirmed to be isolated both prior to and after birth.

METHODS

Retrospective cohort study of all singleton pregnancies were referred for the 1st trimester screening for Down syndrome between January 2004 and December 2006. Cases with NT >95th percentiles who undertook fetal karyotype were analyzed. We evaluated the prevalence of the following: (i) abnormal fetal karyotype, (ii) associated structural abnormalities, (iii) genetic syndromes, and (iv) children needing treatment (i.e. medications or psychopedagogical intervention) at school age.

RESULTS

There were 19 106 women screened for Down syndrome. Among them, 846 (4.4%) had a NT >95th centile, of whom 541 (64.0%) undertook fetal karyotyping, 422 (78.0%) had normal karyotype, two (0.5%) opted for termination of pregnancy, and four (1.0%) ended in miscarriages. Among the 384 cases thought to be "normal" prior to birth, 14 (3.6%) were lost at follow-up and 10 (2.7%) had an associated abnormality diagnosed postnatally. Among the cases confirmed to be isolated, 10/270 (3.7%) were under treatment at the time of telephonic interview with parents.

CONCLUSIONS

Parents should be informed that fetuses with increased NT and normal karyotype need detailed ultrasound scans during pregnancy and detailed pediatric evaluation at birth; if these are normal, the risk from adverse outcome at school age is the same as for general population.

Increased Nuchal Translucency and Early Growth Retardation Related to Confined Placental Mosaicism of Trisomy 16 in a Dichorionic Twin

Confined placental mosaicism (CPM) of trisomy 16 is related to intrauterine growth restriction; however, its association with increased nuchal translucency (NT) has not been sufficiently studied. We report the first case involving a diagnosis of CPM for trisomy 16 in a dichorionic twin. Increased NT (3.7 mm) and 1 week of growth retardation at 12 weeks of gestational age were detected in the affected fetus compared with the normal fetus. Given that the biochemical analytes in maternal serum aneuploidy screening of the abnormal fetus were diluted by the presence of the normal fetus, this method was unreliable as a screening tool. Therefore, in dichorionic twins, ultrasonographic findings such as increased NT and early growth retardation can serve as important indicators for the diagnosis of CPM of trisomy 16.

Neurodevelopmental outcome of fetuses with increased nuchal translucency and apparently normal prenatal and/or postnatal assessment: a systematic review

OBJECTIVES

To systematically review and, when feasible, pool, published data regarding the prevalence of childhood neurodevelopmental delay in fetuses with increased first-trimester nuchal translucency (NT), normal karyotype and absence of structural defects or identifiable syndromes.

METHODS

MEDLINE and SCOPUS searches using combinations of the terms 'nuchal translucency' AND 'outcome*' were complemented by perusal of the references of the retrieved articles and an additional automated search using the 'search for related articles' PubMed function. Only children with a normal karyotype and no structural defects or syndromic abnormalities were included in the analysis. Between-studies heterogeneity was assessed using the I(2) statistic.

RESULTS

The total prevalence of developmental delay in all 17 studies was 28/2458 (1.14%; 95% CI, 0.79-1.64; I(2) = 57.6%). Eight studies (n = 1567) used NT > 99(th) centile as the cut-off; 15 children (0.96%; 95% CI, 0.58-1.58%) were reported as having developmental delay (I(2) = 72.2%). Four studies (n = 669) used the 95(th) centile as the cut-off for increased NT; seven children (1.05%; 95% CI, 0.51-4.88%) were reported as having developmental delay (I(2) = 29.2%). Five studies used 3.0 mm as the cut-off for increased NT; the pooled rate of developmental delay was six of 222 children (2.70%; 95% CI, 1.24-5.77%; I(2) = 0.0%).

CONCLUSION

The rate of neurodevelopmental delay in children with increased fetal NT, a normal karyotype, normal anatomy and no identifiable genetic syndromes does not appear to be higher than that reported for the general population. More large-scale, prospective case-control studies would be needed to enhance the robustness of the results.

Increased nuchal translucency thickness and normal karyotype: time for parental reassurance

OBJECTIVES

To study the outcome of pregnancy in chromosomally normal fetuses with increased nuchal translucency thickness (NT), with respect to fetal loss, structural defects and genetic syndromes with developmental delay, and to provide information that would be helpful for parental counseling on the residual risk of adverse outcome when ultrasound findings are normal.

METHODS

We reviewed the outcome of all pregnancies presenting at the Academic Medical Centre in Amsterdam with increased NT between January 1994 and March 2005. Fetal karyotyping and two-step ultrasound investigation at 13-18 and 20-24 weeks' gestation were offered in all cases. Particular attention was paid to the relationship between normal karyotype, ultrasound findings at the 20-24-week scan and subsequent pregnancy outcome. An adverse outcome was defined as miscarriage, intrauterine death, termination of pregnancy at parental request or the finding of one or more structural defects or genetic disorders.

RESULTS

A total of 675 fetuses with increased NT, known karyotype and known pregnancy outcome was analyzed. A chromosomal anomaly was detected in 224 (33%) fetuses. In 451 (67%) fetuses, the karyotype was normal. The overall incidence of an adverse pregnancy outcome in this group was 19% and, when analyzed according to the initial degree of increase in NT, the likelihood of an adverse outcome increased with increasing NT, ranging from 8% to 80%. 425 fetuses underwent a detailed second-trimester ultrasound scan. Anomalies were detected, at the time of ultrasound or after birth, in 54 (13%) of these fetuses (17 isolated cardiac defects, 14 other structural defects and 23 genetic disorders). An adverse pregnancy outcome was recorded in 4% of cases in which there were normal findings at the 20-week scan. Seven of these cases were classified as 'potentially amenable' to ultrasound detection. With exclusion of these cases, the chance of a healthy baby, if the 20-week scan was completely normal, was 98%. Genetic syndromes with dysmorphic features and neurodevelopmental delay occurred in seven (1.6%) of the fetuses with normal karyotype. In three of these pregnancies, non-specific suspicious ultrasound findings (nuchal edema, mild pyelectasis, pericardial effusion) were observed at the mid-trimester scan and in two others, subtle cardiac defects were detected after delivery. In the remaining two cases (0.5%) the mid-trimester scan was completely normal and no structural defects were observed after delivery.

CONCLUSION

After exclusion of chromosomal anomalies, one out of five fetuses with increased NT has an adverse pregnancy outcome. The chance of an uneventful pregnancy outcome depends on the initial degree of increase in NT. However, if the detailed ultrasound examination at around 20 weeks is normal, a favorable outcome can be expected with confidence, irrespective of initially increased NT.

[Increased nuchal translucency with normal karyotype]

Nuchal translucency (NT) measurement in first trimester screening between 11 and 14 weeks' gestation has now been clearly identified as a marker for aneuploidies and in particular for trisomy 21. Even in the absence of aneuploidy increased fetal nuchal translucency has been shown to be a marker for fetal heart malformations and numerous other fetal defects and genetic syndromes when the measure is>or=95th centile which is around 3,5 mm for each gestational age. Fetuses with NT thickness above the 99th centile and normal karyotype have a high risk of adverse prenatal outcome and this increase in risk is exponential as the nuchal translucency measurement increases. However, among children born alive with normal ultrasound at 22 weeks of gestation, there was no significant association between NT thickness and development at 2 years as assessed by clinical examination and ASQ scores, when with a control population. Counselling should emphasize that when the karyotype is normal and no fetal structural malformation was missed prenatally following resolution of nuchal thickening, the prognosis is not impaired at the age of 2.

Long-term outcome of children born after a first-trimester measurement of nuchal translucency at the 99th percentile or greater with normal karyotype: a prospective study

OBJECTIVE

This study was undertaken to assess the long-term outcome of children born after a first-trimester measurement of nuchal translucency (NT) at the 99th percentile or greater during routine first-trimester screening in an unselected population.

STUDY DESIGN

One hundred sixty-two infants were born alive. Clinical examination as well as a questionnaire to the parents (Ages and Stages Questionnaires [ASQ]) at the age of 2 years were obtained in 160 children. Our study population was compared with an external control group made of the 370 term control children.

RESULTS

The prevalence of abnormal clinical pediatric examination and ASQ results at 2 years were not associated with NT thickness. Comparison with an external control group did not demonstrate an increased incidence of developmental delay.

CONCLUSION

Parents should be informed that when the fetus is shown to be normal by ultrasound at 22-24 weeks of gestation the risk of adverse neonatal outcome or developmental delay in early childhood is not increased.

Prenatal phenotypic overlap of Costello syndrome and severe Noonan syndrome by tri-dimensional ultrasonography

BACKGROUND

Prenatal diagnosis of multiple congenital anomalies is difficult, and usually molecular biology cannot immediately confirm the suspected syndrome. Fetal dysmorphology is useful tool in the diagnosis process, with limitations.

METHODS

We report the thorough prenatal investigation by 2D and 3D ultrasonography in a case of suspected Costello syndrome.

RESULTS

Prenatal abnormalities were: increased nuchal translucency, polyhydramnios, bilateral pyelectasis and ventriculomegaly. Ultrasonographic morphological fetal face analysis found abnormal thickness of the skin in the prefrontal area, thick dysplastic ears, thick lips and deep-set creases in the hands and feet. As Costello and Noonan syndromes overlap, a PTPN11 analysis was done, with presence of a mutation (T854C).

CONCLUSION

Prenatal overlap of feature of severe Noonan syndrome and Costello syndrome is confirmed, with dysmorphological similarities, due to edema of fetal skin in face and extremities.