Véronique Abadie

Association between Zika virus and microcephaly in French Polynesia, 2013–15: a retrospective study

BACKGROUND The emergence of Zika virus in the Americas has coincided with increased reports of babies born with microcephaly. On Feb 1, 2016, WHO declared the suspected link between Zika virus and microcephaly to be a Public Health Emergency of International Concern. This association, however, has not been precisely quantified. METHODS We retrospectively analysed data from a Zika virus outbreak in French Polynesia, which was the largest documented outbreak before that in the Americas. We used serological and surveillance data to estimate the probability of infection with Zika virus for each week of the epidemic and searched medical records to identify all cases of microcephaly from September, 2013, to July, 2015. Simple models were used to assess periods of risk in pregnancy when Zika virus might increase the risk of microcephaly and estimate the associated risk. FINDINGS The Zika virus outbreak began in October, 2013, and ended in April, 2014, and 66% (95% CI 62-70) of the general population were infected. Of the eight microcephaly cases identified during the 23-month study period, seven (88%) occurred in the 4-month period March 1 to July 10, 2014. The timing of these cases was best explained by a period of risk in the first trimester of pregnancy. In this model, the baseline prevalence of microcephaly was two cases (95% CI 0-8) per 10,000 neonates, and the risk of microcephaly associated with Zika virus infection was 95 cases (34-191) per 10,000 women infected in the first trimester. We could not rule out an increased risk of microcephaly from infection in other trimesters, but models that excluded the first trimester were not supported by the data. INTERPRETATION Our findings provide a quantitative estimate of the risk of microcephaly in fetuses and neonates whose mothers are infected with Zika virus. FUNDING Labex-IBEID, NIH-MIDAS, AXA Research fund, EU-PREDEMICS.

Highly conserved non-coding elements on either side of SOX9 associated with Pierre Robin sequence

Pierre Robin sequence (PRS) is an important subgroup of cleft palate. We report several lines of evidence for the existence of a 17q24 locus underlying PRS, including linkage analysis results, a clustering of translocation breakpoints 1.06–1.23 Mb upstream of SOX9, and microdeletions both ∼1.5 Mb centromeric and ∼1.5 Mb telomeric of SOX9. We have also identified a heterozygous point mutation in an evolutionarily conserved region of DNA with in vitro and in vivo features of a developmental enhancer. This enhancer is centromeric to the breakpoint cluster and maps within one of the microdeletion regions. The mutation abrogates the in vitro enhancer function and alters binding of the transcription factor MSX1 as compared to the wild-type sequence. In the developing mouse mandible, the 3-Mb region bounded by the microdeletions shows a regionally specific chromatin decompaction in cells expressing Sox9. Some cases of PRS may thus result from developmental misexpression of SOX9 due to disruption of very-long-range cis-regulatory elements.

CHARGE syndrome: Report of 47 cases and review

The acronym CHARGE refers to a syndrome of unknown cause. Here we report on 47 CHARGE patients evaluated for the frequency of major anomalies, namely coloboma (79%), heart malformation (85%), choanal atresia (57%), growth and/or mental retardation (100%), genital anomalies (34%), ear anomalies (91%), and/or deafness (62%). In addition, we comment on anomalies observed very frequently in neonates and infants with the CHARGE syndrome, including, minor facial anomalies, neonatal brain stem dysfunction with cranial nerve palsy, and, mostly, internal ear anomalies such as semicircular canal hypoplasia that were found in each patient that could be tested. We propose several criteria for poor survival including male gender, central nervous system and/or oesophageal malformations, and bilateral choanal atresia. No predictive factor regarding developmental prognosis could be identified in our series. A significantly higher mean paternal age at conception together with concordance in monozygotic twins and the existence of rare familial cases support the role of genetic factors such as de novo mutation of a dominant gene or subtle sub-microscopic chromosome rearrangement. Finally, the combination of malformations in CHARGE syndrome strongly supports the view that this multiple congenital anomalies/mental retardation syndrome is a polytopic developmental field defect involving the neural tube and the neural crests cells.

Congenital cerebral malformations and dysfunction in fetuses and newborns following the 2013 to 2014 Zika virus epidemic in French Polynesia

We detected an unusual increase in congenital cerebral malformations and dysfunction in fetuses and newborns in French Polynesia, following an epidemic of Zika virus (ZIKV), from October 2013 to March 2014. A retrospective review identified 19 cases, including eight with major brain lesions and severe microcephaly, six with severe cerebral lesions without microcephaly and five with brainstem dysfunction without visible malformations. Imaging revealed profound neurological lesions (septal and callosal disruption, ventriculomegaly, abnormal neuronal migration, cerebellar hypoplasia, occipital pseudocysts, brain calcifications). Amniotic fluid was drawn from seven cases at gestation weeks 20 to 29. ZIKV RNA was detected by RT-PCR and infectious ZIKV isolates were obtained in four of five microcephalic, but not in two non-microcephalic cases with severe brain lesions. Medical termination of pregnancy was performed in eleven cases; two cases with brainstem dysfunction died in the first months of life; six cases are alive, with severe neurological impairment. The results show that four of seven tested fetuses with major neurological injuries were infected with ZIKV in utero. For other non-microcephalic, congenital abnormalities we were not able to prove or exclude ZIKV infection retrospectively. The unusual occurrence of brain malformations or dysfunction without microcephaly following a ZIKV outbreak needs further studies.

Temporal bone anomaly proposed as a major criteria for diagnosis of CHARGE syndrome

The acronym CHARGE defines a non-random clustering of congenital malformations of unknown origin. Classical diagnostic criteria include: 1) one major feature namely coloboma/microphthalmia or choanal atresia, and 2) four of the six features designated in the CHARGE acronym. Interestingly, all CHARGE patients hitherto reported had partial or complete semicircular canal hypoplasia on temporal bone CT-scan. We report on semicircular canal agenesis/hypoplasia in three patients with three to four features of the CHARGE syndrome and neither coloboma nor choanal atresia and we propose to include temporal bone malformations as a major criteria for diagnosis of CHARGE syndrome.

Branchiomotor activities in mouse embryo.

Using a novel isolated hindbrain in vitro preparation, we demonstrate that, in the mouse, branchiomotor activities from trigeminal, facial, glossopharyngeal and vagal nerves start during segmentation, a crucial and conserved period of hindbrain embryogenesis. At embryonic day (E) 10.5, branchiomotor nerves are independently active in bursts, become coactive at a low frequency (about 0.5 min−1 at E12.5, before high frequency (about 15 min−1) fetal breathing starts at E14.5. Comparison with observations in chick reveals a transient episodic rhythmic pattern highly similar in mouse at E13.5 and chick at E7. This pattern is proposed as a marker identifying a phylotypic stage during the development of hindbrain neuronal networks in vertebrates.

Brainstem dysfunction: a possible neuroembryological pathogenesis of isolated Pierre Robin sequence

Abstract. Pierre Robin sequence (posterior U-shape cleft palate, glossoptosis, retrognathia) (PRS) is a frequent and heterogeneous neonatal condition of obscure origin. We show here that orodigestive and cardiorespiratory functional disorders are very frequent in PRS and that these functional disorders, as well as anatomical and embryological data, argue for the involvement of brainstem dysfunction in the pathogenesis of some cases of isolated PRS. A total of 66 infants consecutively admitted for isolated PRS were followed-up with observations and investigations focused on their orodigestive and cardiorespiratory disorders. Neonatal clinical examination and neonatal anatomical aspects of the three orofacial features of the sequence were evaluated. Feeding difficulties and respiratory disorders were recorded and infants were classified according to three grades of severity. The relation between functional severity grade and neonatal orofacial features was evaluated, as well as the relation between functional severity grade and specific criteria characterising oesophageal and laryngeal motility and cardiac orthoparasympathetic imbalance. In the first weeks of life, sucking and swallowing disorders (100%), excessive regurgitation (94%), upper airways obstruction (50%), and cardiac vagal overactivity (59%) were noted. Correlation of anatomical features with functional severity grades was poor except for extreme forms of glossoptosis and retrognathia. Specific anomalies of oesophageal motility, pharyngolaryngeal tone and parasympathetic cardiac regulation were described. These anomalies were more frequent in children with the two higher grades of functional severity. Conclusion: infants with Pierre Robin sequence have early and severe anomalies of orodigestive and cardiorespiratory function which do not appear to be related solely to anatomical features and which require proper medical management. We suggest a prenatal and neonatal brainstem dysfunction as a neuroembryological hypothesis to explain the onset of some cases of Pierre Robin sequence.

Vestibular anomalies in CHARGE syndrome: investigations on and consequences for postural development

Abstract Recently, vestibular anomalies have been described as a frequent feature in children with coloboma-heart-atresia-retarded-genital-ear (CHARGE) syndrome. They are likely to play an important role in the psychomotor retardation affecting these children. In order to test this hypothesis, we prospectively performed complete vestibular investigations in a series of 17 CHARGE syndrome patients including inner ear CT scan and functional vestibular evaluation of both canal and otolith functions. These results were correlated with the postural anomalies observed during the childrens development and showed that vestibular dysfunction is a constant feature in CHARGE syndrome and has very good sensitivity for confirming the diagnosis. Anomalies of semicircular canals were frequently found (94%), easily detectable on CT scan and associated with no response on canal function evaluation. They were considered as partly responsible for the retardation of postural stages. Vestibular functional tests were consistently abnormal but allowed detection of residual otolith function in most patients (94%). All children of this series had an atypical pattern of postural behaviour that we consider to be related to their vestibular anomalies. Residual otolith function seems to have a positive influence for postural development. Conclusion Vestibular investigations are valuable for diagnosis, developmental assessment, and adaptation of specific rehabilitation programmes in CHARGE syndrome patients.

Features of DiGeorge syndrome and CHARGE association in five patients.

We report on five patients presenting with features of two congenital disorders, DiGeorge syndrome (DGS) and CHARGE association. CHARGE association is usually sporadic and its origin is as yet unknown. Conversely, more than 90% of DGS patients are monosomic for the 22q11.2 chromosomal region. In each of the five patients, both cytogenetic and molecular analysis for the 22q11.2 region were normal. In view of the broad clinical spectrum and the likely genetic heterogeneity of both disorders, these cases are consistent with the extended phenotype of either DGS without 22q11.2 deletion or CHARGE association, especially as several features of CHARGE association have been reported in rare patients with 22q11.2 deletion association phenotypes. On the other hand, these could be novel cases of an independent association involving a complex defect of neural crest cells originating from the pharyngeal pouches.

Oroesophageal motor disorders in Pierre Robin syndrome.

Background Feeding disorders are one of the main clinical features in PRS, which combines a posterior U-shaped cleft palate, retrognathia, and glossoptosis. The aim of this study was to evaluate the oral and esophageal motor function of children with PRS without additional neurologic symptoms. Methods All children hospitalized with Pierre Robin syndrome either isolated (n = 27) or associated with Stickler syndrome (n = 8) were included. Clinical evaluation of their oroesophageal disorders and systematic esophageal manometry were performed. Results Feeding disorders were always present, but type of disorder varied from one child to another. Esophageal disorders were frequent and seemed to be resistant to classic gastroesophageal reflux treatment. Eighty-six percent of the children required nasogastric tube feeding for a mean duration of 8.6 months. Esophageal manometric abnormalities were noted in 50% of the children: lower esophageal sphincter hypertonia, failure of lower esophageal sphincter relaxation at deglutition, and esophageal dyskinesia. These clinical and manometric disorders showed a trend to spontaneous regression after 12 months. Conclusion In the current Pierre Robin syndrome series, clinical and manometric anomalies of oroesophageal motility were always present. The authors identified an unusual manometric pattern that has also been described in situations of neurovegetative instability. It could reflect dysregulation of the control of the central pattern generators of swallowing in the brain stem.