Feasibility and Added Value of Fetal DTI Tractography in the Evaluation of an Isolated Short Corpus Callosum: Preliminary Results.

BACKGROUND AND PURPOSE: Prognosis of isolated short corpus callosum is challenging. Our aim was to assess whether fetal DTI tractography can distinguish callosal dysplasia from variants of normal callosal development in fetuses with an isolated short corpus callosum. MATERIALS AND METHODS: This was a retrospective study of 37 cases referred for fetal DTI at 30.4 weeks (range, 25-34 weeks) because of an isolated short corpus callosum less than the 5th percentile by sonography at 26 weeks (range, 22-31 weeks). Tractography quality, the presence of Probst bundles, dysmorphic frontal horns, callosal length (internal cranial occipitofrontal dimension/length of the corpus callosum ratio), and callosal thickness were assessed. Cytogenetic data and neurodevelopmental follow-up were systematically reviewed. RESULTS: Thirty-three of 37 fetal DTIs distinguished the 2 groups: those with Probst bundles (Probst bundles+) in 13/33 cases (40%) and without Probst bundles (Probst bundles-) in 20/33 cases (60%). Internal cranial occipitofrontal dimension/length of the corpus callosum was significantly higher in Probst bundles+ than in Probst bundles-, with a threshold value determined at 3.75 for a sensitivity of 92% (95% CI, 77%-100%) and specificity of 85% (95% CI, 63%-100%). Callosal lipomas (4/4) were all in the Probst bundles- group. More genetic anomalies were found in the Probst bundles+ than in Probst bundles- group (23% versus 10%, P = .08). CONCLUSIONS: Fetal DTI, combined with anatomic, cytogenetic, and clinical characteristics could suggest the possibility of classifying an isolated short corpus callosum as callosal dysplasia and a variant of normal callosal development.

Prevalence of COL4A1 and COL4A2 mutations in severe fetal multifocal hemorrhagic and/or ischemic cerebral lesions.

OBJECTIVE: To establish the prevalence of COL4A1 and COL4A2 gene mutations in fetuses presenting with a phenotype suggestive of cerebral injury. METHODS: This was a single-center retrospective analysis of all cases of fetal cerebral anomalies suggestive of COL4A1 or COL4A2 gene mutation over the period 2009-2018. Inclusion criteria were: (1) severe and/or multifocal hemorrhagic cerebral lesions; (2) multifocal ischemic-hemorrhagic cerebral lesions. These anomalies could be of different ages and associated with schizencephaly or porencephaly. Between fetuses with and those without a mutation, we compared gestational age at the time of diagnosis, parity and fetal gender. RESULTS: Among the 956 cases of cerebral anomaly diagnosed in our center during the 10-year study period, 18 fetuses were identified for inclusion. A pathogenic COL4A1 gene mutation was found in five of these cases, among which four were de-novo mutations. A variant of unknown significance was found in four fetuses: in the COL4A1 gene in one case and in the COL4A2 gene in three cases. No COL4A1 or COL4A2 mutation was found in the remaining nine fetuses. The median (interquartile range) gestational age at diagnosis was significantly lower in cases with a mutation (24 (22-26) weeks) than in cases without a mutation (32 (29.5-34.5) weeks) (P = 0.03). CONCLUSIONS: A phenotype suggestive of cerebral injury was found in 18 of the 956 (1.9%) cases in our population, in 28% of which there was an associated COL4A1 or COL4A2 mutation. COL4A1 and COL4A2 gene mutations should be sought systematically in cases of severe and/or multifocal hemorrhagic or ischemic-hemorrhagic cerebral lesions, with or without schizencephaly or porencephaly. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Using medical exome sequencing to identify the causes of neurodevelopmental disorders: Experience of 2 clinical units and 216 patients.

Although whole-exome sequencing (WES) is the gold standard for the diagnosis of neurodevelopmental disorders (NDDs), it remains expensive for some genetic centers. Commercialized panels comprising all OMIM-referenced genes called "medical exome" (ME) constitute an alternative strategy to WES, but its efficiency is poorly known. In this study, we report the experience of 2 clinical genetic centers using ME for diagnosis of NDDs. We recruited 216 consecutive index patients with NDDs in 2 French genetic centers, corresponded to the daily practice of the units and included non-syndromic intellectual disability (NSID, n = 33), syndromic ID (NSID = 122), pediatric neurodegenerative disorders (n = 7) and autism spectrum disorder (ASD, n = 54). We sequenced samples from probands and their parents (when available) with the Illumina TruSight One sequencing kit. We found pathogenic or likely pathogenic variants in 56 index patients, for a global diagnostic yield of 25.9%. The diagnosis yield was higher in patients with ID as the main diagnosis (32%) than in patients with ASD (3.7%). Our results suggest that the use of ME is a valuable strategy for patients with ID when WES cannot be used as a routine diagnosis tool.

Xq28 duplication including MECP2 in six unreported affected females: what can we learn for diagnosis and genetic counselling?

Duplication of the Xq28 region, involving MECP2 (dupMECP2), has been primarily described in males with severe developmental delay, spasticity, epilepsy, stereotyped movements and recurrent infections. Carrier mothers are usually asymptomatic with an extremely skewed X chromosome inactivation (XCI) pattern. We report a series of six novel symptomatic females carrying a de novo interstitial dupMECP2, and review the 14 symptomatic females reported to date, with the aim to further delineate their phenotype and give clues for genetic counselling. One patient was adopted and among the other 19 patients, seven (37%) had inherited their duplication from their mother, including three mildly (XCI: 70/30, 63/37, 100/0 in blood and random in saliva), one moderately (XCI: random) and three severely (XCI: uninformative and 88/12) affected patients. After combining our data with data from the literature, we could not show a correlation between XCI in the blood or duplication size and the severity of the phenotype, or explain the presence of a phenotype in these females. These findings confirm that an abnormal phenotype, even severe, can be a rare event in females born to asymptomatic carrier mothers, making genetic counselling difficult in couples at risk in terms of prognosis, in particular in prenatal cases.

[Preliminary results from the French study on prenatal repair for fetal myelomeningoceles (the PRIUM study)]. / Résultats préliminaires de l'étude PRIUM : programme de réparation in utero des myéloméningocèles.

OBJECTIVES: To present the preliminary results of the PRIUM study, a French pilot study of prenatal repair for myelomeningoceles (MMC). MATERIAL AND METHODS: The fetal surgery for MMC is offered in cases of patients that did not opt for termination of pregnancy. RESULTS: Thirty-six patients were referred in an 18-month period. Eight patients were not eligible for prenatal repair. Another type of dysraphism was made in 6 cases (one spina-lipoma, 5 cases of limited dorsal myeloschisis). Twenty-two patients were eligible to fetal surgery. A prenatal repair was performed in three cases (14%). Four patients opted for a conventional postnatal treatment. Fifteen patients opted for termination of the pregnancy. CONCLUSION: The establishment of a prenatal repair of MMC protocol in France was justified. The experience of the first 18months of this study however suggests that only a limited number of couples will choose this procedure after specialized counseling in a reference center.

[A difficult transition from childhood to adult healthcare: the case of epilepsy]. / Le difficile passage à l'âge adulte en matière de soins : l'exemple de l'épilepsie.

OBJECTIVE: The purpose of this study was to analyze modalities of the transition from pediatric to adult epilepsy care and patients' acquisition of autonomy. METHOD: This study was conducted using semidirected interviews composed of three major parts: the patient's criteria of transition toward adult healthcare (factors taken into account, anticipation, the patient's opinion, etc.), conditions (teamwork with the neurologists, transmission of the medical record, continuity of health care, etc.), and the role played by social workers and psychologists. We interviewed 10 doctors belonging to six major Parisian hospital units involved in the monitoring of children and adolescents with epilepsy and working in Pediatric Neurology Departments of the Île-de-France region. RESULTS: For most of the doctors, reaching 18 years of age was the major argument taken into account to consider transition to adult care. According to the doctors interviewed, parents are generally worried when their child has to find another doctor (7/10). According to eight out of 10 doctors, the neurologist is selected to take over. The doctors recognize the importance of psychologists and social workers even if they are not always included. The process by which the patient gains autonomy depends a great deal on the role played by the pediatricians and parents, although some parents are very protective. This behavior weakens the patient's capacity for autonomy and it varies according to the degree of his or her physical and/or neurological disabilities. Furthermore, developing autonomy requires interdisciplinary work that is not yet fully in place. CONCLUSION: The lack of structures well-adapted to the uniqueness of each patient and the lack of coordination between the various institutions do not favor the acquisition of autonomy. A network that could efficiently respond to the needs of epileptic patients as well as medical care tailored to adolescents would be the answer to this dilemma.

Prenatal features of isolated subependymal pseudocysts associated with adverse pregnancy outcome.

OBJECTIVES: To identify at prenatal ultrasound (US) the features of apparently isolated subependymal pseudocysts (SEPC) that may indicate underlying pathology and should lead to further investigations. METHODS: This was a retrospective study of cases with SEPC detected on prenatal US and/or magnetic resonance imaging (MRI). Those with apparently isolated SEPC at US were classified into two groups as follows: Group 1 (n = 29): normal prenatal US and MRI (except for SEPC) and normal outcome; Group 2 (n = 12): normal prenatal cerebral US (except for SEPC) and abnormal prenatal cerebral MRI with or without abnormal outcome. A third group (n = 9) included cases with abnormal prenatal US and MRI. The latter cases with obvious cerebral abnormalities at US were excluded from the statistical analysis as they do not represent a diagnostic dilemma for clinicians. Groups 1 and 2 were analyzed, comparing them with respect to their SEPC characteristics (size, number, location in relation to the caudothalamic notch and the ventricular horns and morphology) and extracerebral abnormalities. RESULTS: The mean ± SD SEPC great axis was longer in Group 2 (11.67 ± 5.82 mm) than it was in Group 1 (8.00 ± 5.64 mm) (P = 0.021), suggesting an optimal cut-off for size of SEPC of ≥ 9 mm (sensitivity = 75%, specificity = 62%) to maximize sensitivity for predicting pathological outcome. SEPC adjacent to the temporal horns and SEPC located posterior to the caudothalamic notch were observed more frequently in Group 2, indicating their association with poor outcome (P = 0.003 and P = 0.003, respectively). Atypical morphology and extracerebral abnormalities were observed more frequently in Group 2 (P = 0.013 and P = 0.044, respectively). There was no statistically significant difference between groups for either number or location of cysts along the inferior wall or adjacent to the lateral wall of the frontal horns (P = 0.591 and P = 0.156, respectively). CONCLUSION: When apparently isolated SEPC are observed at prenatal US, further investigations should be performed under the following circumstances: (1) SEPC great axis ≥ 9 mm; (2) SEPC adjacent to the occipital and temporal horns; (3) SEPC located posterior to the caudothalamic notch; (4) SEPC with atypical morphology.

Abnormal shape of the cavum septi pellucidi: an indirect sign of partial agenesis of the corpus callosum.

OBJECTIVE: To describe and assess the presence of a new indirect sign of partial agenesis of the corpus callosum (pACC): an abnormally shaped cavum septi pellucidi (CSP). METHODS: We analyzed retrospectively images from all 71 cases of pACC seen at two referral centers between September 2006 and April 2014. Abnormally shaped CSP was diagnosed when its lateral dimension was greater than its anteroposterior dimension in the axial transthalamic plane, and the incidence of this sign was assessed. We also examined the following variables: gestational age at referral, indication for referral, which (if any) of the four corpus callosal segments were abnormal, presence of other, previously established, indirect signs of callosal agenesis (ACC) and presence of additional cerebral or extracerebral anomalies. RESULTS: In 56 of the 71 (79%) cases, the CSP was measurable; it was abnormally shaped in 19 (34%) of these cases, 15 (79%) of which had no other indirect signs of pACC. Of 23 cases with isolated pACC and no other indirect signs, 12 (52%) had an abnormally shaped CSP. CONCLUSIONS: In a significant proportion of cases of pACC detected prenatally, the shape of the CSP is abnormal. This should be considered an additional indirect sign of pACC, and is frequently the only clue to the diagnosis. When observing this sign in a screening context, pACC should be considered, and an attempt to visualize the corpus callosum directly in the midsagittal plane is suggested.

Prenatal unilateral cerebellar hypoplasia in a series of 26 cases: significance and implications for prenatal diagnosis.

OBJECTIVE: To define imaging patterns of unilateral cerebellar hypoplasia (UCH), discuss possible pathophysiological mechanisms and underline the etiology and prognosis associated with these lesions. METHODS: In this retrospective study we reviewed the charts of 26 fetuses diagnosed between 2003 and 2011 with UCH, defined by asymmetrical cerebellar hemispheres with or without decreased transverse cerebellar diameter. The review included analysis of the anatomy of the cerebellar hemispheres, including foliation, borders and parenchymal echogenicity, and of the severity of the hypoplasia. Data from clinical and biological work-up and follow-up were obtained. RESULTS: Our series could be divided into two groups according to whether imaging features changed progressively or remained constant during follow-up. In Group 1 (n = 8), the progression of imaging features, echogenic cerebellar changes and/or hyposignal in T2*-weighted MR images were highly suggestive of ischemic/hemorrhagic insult. In Group 2 (n = 18), imaging features remained constant during follow-up; UCH was associated with abnormal foliation in three proven cases of clastic lesions, a cystic lesion was noted in three cases of PHACE (posterior fossa anomalies, hemangioma, arterial anomalies, cardiac abnormalities/aortic coarctation, eye abnormalities) syndrome and, in the remaining cases, UCH remained unchanged, with no imaging pattern typical of hemorrhage. In 24 cases the infant was liveborn and follow-up was continued in 23, for a mean period of 3 years. Among these, neurological complications were identified in seven (in one of seven (at a mean of 46 months) in Group 1 and in six of 16 (at a mean of 35 months) in Group 2). The surface loss of cerebellar hemisphere was > 50% in 19/24 fetuses and the vermis was clearly normal in appearance in 19/24. Predisposing factors for fetal vascular insult were identified in eight cases: these included maternal alcohol addiction, diabetes mellitus, congenital cytomegalovirus infection and pathological placenta with thrombotic vasculopathy and infarctions. CONCLUSION: UCH is defined as a focal lesion of the cerebellum that may be secondary to hemorrhage and/or ischemic insult, suggesting a clastic origin, particularly when imaging follow-up reveals changes over time. UCH may also be a clue for the prenatal diagnosis of PHACE syndrome. The amount of surface loss of cerebellar hemisphere does not correlate with poor prognosis. UCH with normal vermis is often associated with normal outcome.

Prenatal abnormal features of the fourth ventricle in Joubert syndrome and related disorders.

Joubert syndrome and related disorders (JSRD) are characterized by absence or underdevelopment of the cerebellar vermis and a malformed brainstem. This family of disorders is a member of an emerging class of diseases called ciliopathies. We describe the abnormal features of the brain, particularly the fourth ventricle, in seven fetuses affected by JSRD. In three cases abnormality of the fourth ventricle was isolated and in four cases there were associated malformations. The molar tooth sign (MTS) was always present and visible on two-dimensional ultrasound and, when performed, on three-dimensional ultrasound and magnetic resonance imaging. The fourth ventricle was always abnormal, in both axial and sagittal views, presenting pathognomonic deformities. It is important to identify JSRD, preferably prenatally or at least postnatally, due to its high risk of recurrence of about 25%. A detailed prenatal assessment of the fourth ventricle in several views may help to achieve this goal.

Normal EEG in childhood: from neonates to adolescents.

The important EEG changes that occur throughout childhood are a major challenge for the neurophysiologist. These reflect brain maturation, which is especially fast during the first year of life. This article describes normal EEG features and variants, characteristic patterns of development, as well as some patterns that are unusual for age, from the neonatal period to adolescence. We also describe how to adapt techniques and prepare patients in order to get interpretable records of appropriate duration, in neonates, infants, and young children.

Periventricular nodular heterotopia on prenatal ultrasound and magnetic resonance imaging.

OBJECTIVES: To describe the prenatal ultrasound and magnetic resonance imaging (MRI) findings suggestive of periventricular nodular heterotopia (PNH). METHODS: This retrospective case series included fetuses referred to our institution for brain MRI between 2007 and 2012, which were diagnosed with PNH and confirmed by postnatal MRI or autopsy. The type of PNH, associated ventriculomegaly and associated malformations are reported. RESULTS: We included 11 fetuses (nine female, two male) with a mean gestational age at diagnosis of 31 (range, 23-34) weeks. PNH lesions were small and diffuse (n = 7), large and multiple (n = 1) or single (n = 3). A targeted ultrasound examination performed before fetal MRI missed the diagnosis in four cases (one diffuse and three single); a further ultrasound examination performed after MRI diagnosed PNH in two of these four cases. Ventriculomegaly was present in six cases (four unilateral and two bilateral). PNH appeared in all cases as nodules of intermediate echogenicity protruding into the ventricular lumen. In all cases of diffuse PNH, the frontal horns and bodies of the lateral ventricles appeared square in shape on coronal view, with irregular borders on axial view. Associated cerebral malformations were observed in seven cases and included corpus callosal agenesis (n = 4, with additional malformations in two) and retrocerebellar cyst (n = 3). Extracerebral malformations were also present in two cases. Maternal MRI was performed in five of the six cases of isolated small and diffuse PNH in female fetuses, and demonstrated PNH in two of these. CONCLUSION: PNH is underdiagnosed at prenatal ultrasound, even on targeted scans. Irregular ventricular borders on axial view and irregular square-shaped lateral ventricles on coronal view are suggestive of PNH at prenatal ultrasound.

[Diagnostic investigations for an unexplained developmental disability]. / Stratégie d'exploration d'une déficience intellectuelle inexpliquée.

Developmental disability/mental retardation is a major public health problem and a common cause of consultation in pediatrics, neuropediatrics, and genetics. Etiologies of mental retardation are highly heterogeneous. Diagnostic strategies have been explored in a small number of consensus publications, essentially from English-speaking countries. In these publications, the utility of the conventional karyotype, fragile X screening, metabolic workup, and brain imaging were discussed. Recently, investigations in mental disabilities have been dramatically modified by molecular cytogenetics and the emergence of new metabolic pathologies. Based on the published experiments, the Reference centers for rare disease network "mental deficiencies with rare causes" elaborated an updated protocol for the investigation of nonsyndromal mental disability that takes into account recent innovations in genetics and genomics. Whenever local facilities make it possible, we recommend array CGH investigation as the first step or, when CGH is not available, a combination of classic karyotype with systematic screening of telomeric and interstitial rearrangements by MLPA, fragile X screening in both sexes, and a reorientation of metabolic screening toward certain diseases that have recently been described: congenital disorders of glycosylation (CDG), thyroid hormone carrier deficiency, and creatine metabolism deficiency. We recommend MRI imaging only if head size is abnormal, if neurological examination is abnormal, or regression occurs if walking is not achieved by 2 years, or if development is severely delayed.

Biometry of the corpus callosum in children: MR imaging reference data.

BACKGROUND AND PURPOSE: The availability of data relating to the biometry of the CC in children that are easy to use in daily practice is limited. We present a reference biometry of the CC in MR imaging in a large cohort of children. MATERIALS AND METHODS: Cerebral MR imaging studies of children with normal examination findings were selected retrospectively. Children born preterm and those with or at risk of developing cerebral malformations were excluded. The following parameters were measured: FOD, APD, LCC, GT, BT, IT, ST, and the S/T. Inter- and intraobserver agreement and sex effect were evaluated. RESULTS: Six hundred twenty-two children were included (320 boys, 302 girls), ranging from 1 day to 15 years of age. Normal values (from the 3rd to 97th percentile) are provided for each parameter. All parameters showed rapid growth up to 3 years of age followed by slower (FOD, APD, LCC, GT and ST) or absent (S/T) growth. Growth of BT and IT was completed by 7-8 years. CC modeling (IT/ST) was completed by 3 years. FOD was larger in boys from the age of 1 year (statistically significant). The other parameters did not show any sex effect. Inter- and intraobserver agreement was excellent for all parameters except for IT. CONCLUSIONS: As measured, our data result in easy and reproducible MR imaging biometry of the CC in children.

Correlation between pre- and postnatal cerebral magnetic resonance imaging.

OBJECTIVES: To evaluate the diagnostic accuracy of fetal cerebral magnetic resonance imaging (MRI) on a large cohort and to compare pre- and postnatal MRI data. METHODS: This prospective study included all cases referred to our unit for fetal cerebral MRI examination between June 2006 and December 2009 and which underwent at least one postnatal MRI examination. Cases in which there was termination of pregnancy, fetal death or stillbirth were excluded. The pre- and postnatal diagnoses established by MRI were compared and divided into five subgroups: same diagnosis on pre- and postnatal MRI (Group 1); same diagnosis but different appearance related to the natural course of the disease (Group 2); different diagnosis (related to limitations of fetal MRI) (Group 3); same diagnosis but with additional findings discovered on postnatal MRI examination (Group 4); or same diagnosis but different appearance related to the natural course of the disease (as in Group 2) and associated with additional findings discovered on postnatal MRI examination (Group 5). The prognostic impact of a possible disagreement between pre- and postnatal findings was evaluated. RESULTS: One hundred fetuses were included. Fetal MRI was performed at a mean gestational age of 33 (range, 24-39) weeks and postnatal MRI at a mean age of 3.5 months. There were 53 cases classified as Group 1, 32 in Group 2, four in Group 3, 10 in Group 4 and one in Group 5. Thus, in 15 cases (Groups 3-5), there were discrepancies between pre- and postnatal findings (mostly related to corpus callosum anatomy, cortical and migration disorders). The discrepancy was judged to have a prognostic impact in 9/15 cases. Two postnatal MRI examinations were performed in eight cases, in one of which the second examination showed subependymal heterotopia which were not detectable on the first examination. CONCLUSION: Pre- and postnatal MRI data showed good agreement in 85% of cases. There was disagreement with a prognostic impact in 9% of cases.

Pediatric outcome of children with the prenatal diagnosis of isolated septal agenesis.

BACKGROUND: Isolated Septal Agenesis (SA) is a rare disease with clinical outcomes (especially neurological outcomes) that are unknown. The purpose of this study was to evaluate the clinical outcome of these children. METHODS: We conducted a retrospective multicenter study of 17 children with an isolated SA or SA combined with a moderate ventricular dilatation (VD) that was diagnosed antenatally and confirmed by a magnetic resonance imaging (MRI) performed in the antenatal period. RESULTS: Of the 17 children, 14 had normal neurological examinations, 2 had language development delay and visuo-spatial dyspraxia, and 3 of the 17 children had behavioral problems. Eight children had neuropsychological evaluations, and the results were normal in six cases. There were 3 cases of septo-optic dysplasia (SOD) diagnosed postnatally, which highlighted the difficulties in assessing the optic tract and hypothalamic-pituitary region in antenatal imaging. Language delay and behavioral disorders were the main abnormalities at follow-up. CONCLUSION: The discovery of an isolated SA reveals the difficulties of prenatal diagnosis to correlate the neurological and functional prognosis to morphological findings. The prognosis seemed to be good. It appears necessary to improve the diagnostic performance of fetal brain imaging and to follow-up these children prospectively to assess their long-term cognitive-behavioral outcomes.

Prenatal diagnosis of 18q-syndrome: a case of fetal mosaicism with a normal karyotype in chorionic villi.

We report a case of fetoplacental discrepancy with normal karyotype on chorionic villi and deletion of the long arm of chromosome 18 on amniotic fluid. Cytogenetic tests were repeated because of a short corpus callosum on ultrasound examination. This 18q-syndrome has been reported to be associated with poor neurodevelopmental outcome.

[Impact of prenatal corpus callosum agenesis diagnosis on pregnancy outcome. Evaluation of 155 cases between 2000 and 2006]. / Impact du dépistage anténatal des agénésies du corps calleux sur le devenir des grossesses. Etude de 155 dossiers de 2000 à 2006.

The purpose of this study was to investigate the changes between 2000 and 2006 in pregnancy outcome when a diagnosis of either isolated or associated fetal corpus callosum agenesis (CCA) was made, given that beginning in 2003, the information provided to couples facing this problem related a good prognosis in nearly 80 % of cases of isolated CCA and a poor prognosis in 20 % of cases. We retrospectively analyzed all pregnancies with a fetal diagnosis of CCA between 2000 and 2006 (n=155) and compared two periods: the first group from 2000 to June 2003, the second from July 2003 to 2006. For each group, we analyzed the type of CCA during pregnancy - either isolated or associated - and the outcome of pregnancy. We compared the rate of pregnancy termination before and after 2003 and analyzed the accuracy of the prenatal CCA diagnosis. Of the 155 patients studied, 62 terminated the pregnancy. The overall rate of termination decreased from 31/70 to 31/85. When CCA was said to be isolated prenatally, the rate of pregnancy termination fell from 13/35 to 9/44 (-17 %) (p<0.05). Nine diagnoses of CCA were corrected after birth or by postmortem examination. Improvement of prenatal diagnosis requires better quality of prenatal screening, with a more systematic study of dysmorphic features, a study of correlations between the type of CCA and the neurological prognosis, and more genetic studies.

Prenatal and postnatal follow-up of a fetal interhemispheric arachnoid cyst with partial corpus callosum agenesis, asymmetric ventriculomegaly and localized polymicrogyria. Case report.

We report a case of a fetal interhemispheric arachnoid cyst associated with partial callosal agenesis and asymmetric ventriculomegaly. After second trimester ultrasound diagnosis and evaluation, magnetic resonance imaging (MRI) at 28 weeks showed polymicrogyria laterally to the cyst. The parents decided to continue the pregnancy. The diagnosis was confirmed after birth by transfontanellar ultrasound examination and MRI. In the neonatal period, the child was sleepy and showed axial hypotonia. At 1 month of age, he had a normal neurological examination. Cyst-peritoneal shunting was performed at 5 weeks of age because the cyst increased markedly in size, and shunt revision was required at 8 months of age. At 17 months, he had mild left-side hemiparesis but he could walk alone and had begun to speak. To date, the child never experienced seizures. We review other published cases and discuss the postnatal outcome of this rare association.