[Show abstract][Hide abstract] ABSTRACT: Objective
To describe investigate the outcomes of a pregnancy after a second- or third-trimester intrauterine fetal death (IUFD).
A prospective observational study was conducted at Trousseau Hospital (Paris, France) between 1996 and 2011. The first ongoing pregnancy in women who had had a previous IUFD was monitored. Management of their treatment was according to a standardized protocol. Recurrence of fetal death was the main outcome criterion.
The subsequent pregnancies of 87 women who had experienced at least one previous IUFD were followed up. The cause of previous IUFD was placental in 50 (57%) women, unknown in 19 (22%), adnexal in 12 (14%), metabolic in 2 (2%), and malformative in 4 (5%). Three (3%) participants had another stillbirth. Overall, obstetric complications occurred in 34 (39%) pregnancies (including 22 [25%] preterm births, 5 [6%] small for gestational age, and 6 [7%] maternal vascular complications). Obstetric complications were significantly more common among women whose previous stillbirth had been due to placental causes than among those affected by other causes (P = 0.02).
Most pregnancies after IUFD resulted in a live birth; however, adverse obstetric outcomes were more common when the previous stillbirth was due to placental causes.
International Journal of Gynecology & Obstetrics 12/2014; · 1.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Complex cortical malformations associated with mutations in tubulin genes are commonly referred to as "Tubulinopathies". To further characterize the mutation frequency and phenotypes associated with tubulin mutations, we studied a cohort of 60 foetal cases. Twenty-six tubulin mutations were identified, of which TUBA1A mutations were the most prevalent (19 cases), followed by TUBB2B (6 cases) and TUBB3 (one case). Three subtypes clearly emerged. The most frequent (n = 13) was microlissencephaly with corpus callosum agenesis, severely hypoplastic brainstem and cerebellum. The cortical plate was either absent (6/13), with a 2-3 layered pattern (5/13) or less frequently thickened (2/13), often associated with neuroglial overmigration (4/13). All cases had voluminous germinal zones and ganglionic eminences. The second subtype was lissencephaly (n = 7), either classical (4/7) or associated with cerebellar hypoplasia (3/7) with corpus callosum agenesis (6/7). All foetuses with lissencephaly and cerebellar hypoplasia carried distinct TUBA1A mutations, while those with classical lissencephaly harbored recurrent mutations in TUBA1A (3 cases) or TUBB2B (1 case). The third group was polymicrogyria-like cortical dysplasia (n = 6), consisting of asymmetric multifocal or generalized polymicrogyria with inconstant corpus callosum agenesis (4/6) and hypoplastic brainstem and cerebellum (3/6). Polymicrogyria was either unlayered or 4-layered with neuronal heterotopias (5/6) and occasional focal neuroglial overmigration (2/6). Three had TUBA1A mutations and 3 TUBB2B mutations. Foetal TUBA1A tubulinopathies most often consist in microlissencephaly or classical lissencephaly with corpus callosum agenesis, but polymicrogyria may also occur. Conversely, TUBB2B mutations are responsible for either polymicrogyria (4/6) or microlissencephaly (2/6).
[Show abstract][Hide abstract] ABSTRACT: The phenotypic spectrum of GLI3 mutations includes autosomal dominant Greig cephalopolysyndactyly syndrome (GCPS) and Pallister-Hall syndrome (PHS). PHS was first described as a lethal condition associating hypothalamic hamartoma, postaxial or central polydactyly, anal atresia and bifid epiglottis. Typical GCPS combines polysyndactyly of hands and feet and craniofacial features. Genotype-phenotype correlations have been found both for the location and the nature of GLI3 mutations, highlighting the bifunctional nature of GLI3 during development. Here we report on the molecular and clinical study of 76 cases from 55 families with either a GLI3 mutation (49 GCPS and 21 PHS), or a large deletion encompassing the GLI3 gene (6 GCPS cases). Most of mutations are novel and consistent with the previously reported genotype-phenotype correlation. Our results also show a correlation between the location of the mutation and abnormal corpus callosum observed in some patients with GCPS. Fetal PHS observations emphasize on the possible lethality of GLI3 mutations and extend the phenotypic spectrum of malformations such as agnathia and reductional limbs defects. GLI3 expression studied by in situ hybridization during human development confirms its early expression in target tissues.European Journal of Human Genetics advance online publication, 16 April 2014; doi:10.1038/ejhg.2014.62.
European journal of human genetics: EJHG 04/2014; · 3.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Mandibulofacial dysostosis, Guion-Almeida type (MFDGA) is a recently delineated multiple congenital anomalies/mental retardation syndrome characterized by the association of mandibulofacial dysostosis (MFD) with external ear malformations, hearing loss, cleft palate, choanal atresia, microcephaly, intellectual disability, oesophageal atresia (OA), congenital heart defects (CHDs) and radial ray defects. MFDGA emerges as a clinically recognizable entity, long underdiagnosed due to highly variable presentations. The main differential diagnoses are CHARGE and Feingold syndromes, oculoauriculovertebral spectrum and other MFDs. EFTUD2, located on 17q21.31, encodes a component of the major spliceosome and is disease-causing in MFDGA, due to heterozygous loss-of-function mutations. Here, we describe a series of 36 cases of MFDGA, including 24 previously unreported cases, and we review the literature in order to delineate the clinical spectrum ascribed to EFTUD2 loss-of-function. MFD, external ear anomalies and intellectual deficiency occur at a higher frequency than microcephaly. We characterize the evolution of the facial gestalt at different ages and describe novel renal and cerebral malformations. The most frequent extracranial malformation in this series is OA, followed by CHDs and skeletal abnormalities. MFDGA is probably more frequent than other syndromic MFDs such as Nager or Miller syndromes. Although the wide spectrum of malformations complicates diagnosis, characteristic facial features provide a useful handle. This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: Non-syndromic arthrogryposis multiplex congenita (AMC) is characterized by multiple congenital contractures resulting from reduced fetal mobility. Genetic mapping and whole exome sequencing were performed in 31 multiplex and/or consanguineous undiagnosed AMC families. Although this approach identified known AMC genes, we here report pathogenic mutations in two new genes. Homozygous frameshift mutations in CNTNAP1 were found in four unrelated families. Patients showed a marked reduction in motor nerve conduction velocity (<10 m/sec) and transmission electron microscopy (TEM) of sciatic nerve in the index cases revealed severe abnormalities of both nodes of Ranvier width and myelinated axons. CNTNAP1 encodes CASPR, an essential component of node of Ranvier domains which underly saltatory conduction of action potentials along myelinated axons, an important process for neuronal function. A homozygous missense mutation in Adenylate Cyclase 6 gene (ADCY6) was found in another family characterized by a lack of myelin in the Peripheral Nervous System (PNS) as determined by TEM. Morpholino knockdown of the zebrafish orthologs led to severe and specific defects in peripheral myelin in spite of the presence of Schwann cells. ADCY6 encodes a protein that belongs to adenylate cyclase family responsible for the synthesis of cAMP. Elevation of cAMP can mimic axonal contact in vitro and upregulates myelinating signals. Our data indicate an essential and so far unknown role of ADCY6 in PNS myelination likely through the cAMP pathway. Mutations of genes encoding proteins of Ranvier domains or involved in myelination of Schwann cells are responsible for novel and severe human axoglial diseases.
Human Molecular Genetics 12/2013; · 7.69 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Nevus sebaceous (NS) is a complex hamartoma most commonly found on the scalp, face and neck and is often present at birth although some may be diagnosed later in infancy. We report the first prenatal diagnosis of isolated NS that presented at 19 weeks' gestation as a large and exophytic tumors of the scalp. This case emphasizes the crucial role of ultrasound examination performed with high frequency probes, which revealed associated diffuse lesions of the face. Identification of such a facial involvement could have a dramatic prognostic impact. This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: Anophthalmia and Microphthalmia (AM) are the most severe malformations of the eye, corresponding respectively to reduced size or absent ocular globe. Wide genetic heterogeneity has been reported and different genes have been demonstrated to be causative of syndromic and non-syndromic forms of AM. We screened seven AM genes (GDF6, FOXE3, OTX2, PAX6, RAX, SOX2, and VSX2) in a cohort of 150 patients with isolated or syndromic AM. The causative genetic defect was identified in 21 % of the patients (32/150). Point mutations were identified by direct sequencing of these genes in 25 patients (13 in SOX2, 4 in RAX, 3 in OTX2, 2 in FOXE3, 1 in VSX2, 1 in PAX6, and 1 in GDF6). In addition 8 gene deletions (5 SOX2, 2 OTX2 and 1 RAX) were identified using a semi-quantitative multiplex PCR (QMPSF). The causative genetic defect was identified in 21 % of the patients. This result contributes to our knowledge of the molecular basis of AM, and will facilitate accurate genetic counselling.
[Show abstract][Hide abstract] ABSTRACT: In the context of prenatal diagnosis of malformation, knowledge of “similar” and resolved cases (i.e. previous cases with a diagnosis validated by fetus autopsy) is essential for diagnosis orientation. Therefore, access to biomedical data accumulated over the years by fetopathology experts specializing in the study of foetal malformations is crucial. This work addresses the imperious need to gather all the data and make it accessible easily for best use of this collective memory. Our research hypothesis is as follows: scanning electronic records will bring added value in terms of knowledge, allowing to build a knowledge-base of the domain. The files will be structured and enriched by indexing using ontological and terminological resources and their links with external knowledge (publications, databases). Such a database will provide access to similar cases.
[Show abstract][Hide abstract] ABSTRACT: L1 syndrome results from mutations in the L1CAM gene located at Xq28. It encompasses a wide spectrum of diseases, X-linked hydrocephalus being the most severe phenotype detected in utero, and whose pathophysiology is incompletely understood. The aim of this study was to report detailed neuropathological data from patients with mutations, to delineate the neuropathological criteria required for L1CAM gene screening in foetuses by characterizing the sensitivity, specificity and positive predictive value of the cardinal signs, and to discuss the main differential diagnoses in non-mutated foetuses in order to delineate closely related conditions without L1CAM mutations. Neuropathological data from 138 cases referred to our genetic laboratory for screening of the L1CAM gene were retrospectively reviewed. Fifty-seven cases had deleterious L1CAM mutations. Of these, 100 % had hydrocephalus, 88 % adducted thumbs, 98 % pyramidal tract agenesis/hypoplasia, 90 % stenosis of the aqueduct of Sylvius and 68 % agenesis/hypoplasia of the corpus callosum. Two foetuses had L1CAM mutations of unknown significance. Seventy-nine cases had no L1CAM mutations; these were subdivided into four groups: (1) hydrocephalus sometimes associated with corpus callosum agenesis (44 %); (2) atresia/forking of the aqueduct of Sylvius/rhombencephalosynapsis spectrum (27 %); (3) syndromic hydrocephalus (9 %), and (4) phenocopies with no mutations in the L1CAM gene (20 %) and in whom family history strongly suggested an autosomal recessive mode of transmission. These data underline the existence of closely related clinical entities whose molecular bases are currently unknown. The identification of the causative genes would greatly improve our knowledge of the defective pathways involved in these cerebral malformations.
[Show abstract][Hide abstract] ABSTRACT: Objectives
To evaluate the management of prenatally diagnosed cleft lip with or without cleft palate and the immediate postnatal outcome.
Material and methods
Retrospective study of all cases of cleft lip with or without cleft palate referred to our fetal medicine unit, between January 2005 and January 2011. The anatomical type of cleft, associated malformations, and the postnatal outcome were reviewed.
Forty-three cases of fetal cleft lip with or without cleft palate were reviewed. The mean gestational age at diagnosis was 24 weeks ± 4. The postnatal distribution of clefts was: 30 cleft lip and palate (70%) and 13 cleft lip (30%). The prenatal diagnosis of the cleft type was exact in 27 cases (62.8%). Nine cases had associated anomalies (21%), detected prenatally in three cases (37.5%). There was no karyotypical abnormality. Six pregnancies were terminated (14%). The immediate postnatal outcome was comparable with unselected newborns.
The prenatal diagnosis of cleft lip with or without cleft palate is correct, with two thirds of exact diagnoses. Large clefts palate are the best detected. Associated malformations cannot always be diagnosed by prenatal ultrasound, but have to be searched for because they modify the fetal outcome.
Journal de Gynécologie Obstétrique et Biologie de la Reproduction. 04/2013; 42(2):151–158.
[Show abstract][Hide abstract] ABSTRACT: Oral-facial-digital syndrome type VI (OFD VI) is characterized by the association of malformations of the face, oral cavity and extremities, distinguished from the 12 other OFD syndromes by cerebellar and metacarpal abnormalities. Cerebellar malformations in OFD VI have been described as a molar tooth sign (MTS), thus, including OFD VI among the «Joubert syndrome related disorders» (JSRD). OFD VI diagnostic criteria have recently been suggested: MTS and one or more of the following: 1) tongue hamartoma(s) and/or additional frenula and/or upper lip notch; 2) mesoaxial polydactyly of hands or feet; 3) hypothalamic hamartoma. In order to further delineate this rare entity, we present the neurological and radiological data of 6 additional OFD VI patients. All patients presented oral malformations, facial dysmorphism and distal abnormalities including frequent polydactyly (66%), as well as neurological symptoms with moderate to severe mental retardation. Contrary to historically reported patients, mesoaxial polydactyly did not appear to be a predominant clinical feature in OFD VI. Sequencing analyses of the 14 genes implicated in JSRD up to 2011 revealed only an OFD1 frameshift mutation in one female OFD VI patient, strengthening the link between these two oral-facial-digital syndromes and JSRD.
European journal of medical genetics 03/2013; · 1.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cobblestone lissencephaly is a peculiar brain malformation with characteristic radiological anomalies. It is defined as cortical dysplasia that results when neuroglial overmigration into the arachnoid space forms an extracortical layer that produces agyria and/or a "cobblestone" brain surface and ventricular enlargement. Cobblestone lissencephaly is pathognomonic of a continuum of autosomal-recessive diseases characterized by cerebral, ocular, and muscular deficits. These include Walker-Warburg syndrome, muscle-eye-brain disease, and Fukuyama muscular dystrophy. Mutations in POMT1, POMT2, POMGNT1, LARGE, FKTN, and FKRP identified these diseases as alpha-dystroglycanopathies. Our exhaustive screening of these six genes, in a cohort of 90 fetal cases, led to the identification of a mutation in only 53% of the families, suggesting that other genes might also be involved. We therefore decided to perform a genome-wide study in two multiplex families. This allowed us to identify two additional genes: TMEM5 and ISPD. Because TMEM has a glycosyltransferase domain and ISPD has an isoprenoid synthase domain characteristic of nucleotide diP-sugar transferases, these two proteins are thought to be involved in the glycosylation of dystroglycan. Further screening of 40 families with cobblestone lissencephaly identified nonsense and frameshift mutations in another four unrelated cases for each gene, increasing the mutational rate to 64% in our cohort. All these cases displayed a severe phenotype of cobblestone lissencephaly A. TMEM5 mutations were frequently associated with gonadal dysgenesis and neural tube defects, and ISPD mutations were frequently associated with brain vascular anomalies.
The American Journal of Human Genetics 12/2012; 91(6):1135-43. · 11.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: : Oesophageal atresia (OA) and mandibulofacial dysostosis (MFD) are two congenital malformations for which the molecular bases of syndromic forms are being identified at a rapid rate. In particular, the EFTUD2 gene encoding a protein of the spliceosome complex has been found mutated in patients with MFD and microcephaly (MIM610536). Until now, no syndrome featuring both MFD and OA has been clearly delineated.
: We report on 10 cases presenting with MFD, eight of whom had OA, either due to de novo 17q21.31 deletions encompassing EFTUD2 and neighbouring genes or de novo heterozygous EFTUD2 loss-of-function mutations. No EFTUD2 deletions or mutations were found in a series of patients with isolated OA or isolated oculoauriculovertebral spectrum (OAVS).
: These data exclude a contiguous gene syndrome for the association of MFD and OA, broaden the spectrum of clinical features ascribed to EFTUD2 haploinsufficiency, define a novel syndromic OA entity, and emphasise the necessity of mRNA maturation through the spliceosome complex for global growth and within specific regions of the embryo during development. Importantly, the majority of patients reported here with EFTUD2 lesions were previously diagnosed with Feingold or CHARGE syndromes or presented with OAVS plus OA, highlighting the variability of expression and the wide range of differential diagnoses.
Journal of Medical Genetics 12/2012; 49(12):737-46. · 5.70 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND: CHARGE syndrome is a rare, usually sporadic disorder of multiple congenital anomalies ascribed to a CHD7 gene mutation in 60% of cases. Although the syndrome is well characterised in children, only one series of 10 fetuses with CHARGE syndrome has been reported to date. Therefore, we performed a detailed clinicopathological survey in our series of fetuses with CHD7 mutations, now extended to 40 cases. CHARGE syndrome is increasingly diagnosed antenatally, but remains challenging in many instances. METHOD: Here we report a retrospective study of 40 cases of CHARGE syndrome with a CHD7 mutation, including 10 previously reported fetuses, in which fetal or neonatal clinical, radiological and histopathological examinations were performed. RESULTS: Conversely to postnatal studies, the proportion of males is high in our series (male to female ratio 2.6:1) suggesting a greater severity in males. Features almost constant in fetuses were external ear anomalies, arhinencephaly and semicircular canal agenesis, while intrauterine growth retardation was never observed. Finally, except for one, all other mutations identified in our antenatal series were truncating, suggesting a possible phenotype-genotype correlation. CONCLUSIONS: Clinical analysis allowed us to refine the clinical description of CHARGE syndrome in fetuses, describe some novel features and set up diagnostic criteria in order to help the diagnosis of CHARGE syndrome after termination of pregnancies following the detection of severe malformations.
Journal of Medical Genetics 09/2012; · 5.70 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: OBJECTIVES: To evaluate the management of prenatally diagnosed cleft lip with or without cleft palate and the immediate postnatal outcome. MATERIAL AND METHODS: Retrospective study of all cases of cleft lip with or without cleft palate referred to our fetal medicine unit, between January 2005 and January 2011. The anatomical type of cleft, associated malformations, and the postnatal outcome were reviewed. RESULTS: Forty-three cases of fetal cleft lip with or without cleft palate were reviewed. The mean gestational age at diagnosis was 24 weeks±4. The postnatal distribution of clefts was: 30 cleft lip and palate (70%) and 13 cleft lip (30%). The prenatal diagnosis of the cleft type was exact in 27 cases (62,8%). Nine cases had associated anomalies (21%), detected prenatally in three cases (37,5%). There was no karyotypical abnormality. Six pregnancies were terminated (14%). The immediate postnatal outcome was comparable with unselected newborns. CONCLUSION: The prenatal diagnosis of cleft lip with or without cleft palate is correct, with two thirds of exact diagnoses. Large clefts palate are the best detected. Associated malformations cannot always be diagnosed by prenatal ultrasound, but have to be searched for because they modify the fetal outcome.
Journal de Gynécologie Obstétrique et Biologie de la Reproduction 09/2012; · 0.45 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The lethal short rib polydactyly syndromes (SRP type I-IV) are characterised by notably short ribs, short limbs, polydactyly, multiple anomalies of major organs, and autosomal recessive mode of inheritance. Among them, SRP type II (Majewski; MIM 263520) is characterised by short ovoid tibiae or tibial agenesis and is radiographically closely related to SRP type IV (Beemer-Langer; MIM 269860) which is distinguished by bowed radii and ulnae and relatively well tubulated tibiae. NEK1 mutations have been recently identified in SRP type II. Double heterozygosity for mutations in both NEK1 and DYNC2H1 in one SRP type II case supported possible digenic diallelic inheritance.
The aim of this study was to screen DYNC2H1 and NEK1 in 13 SRP type II cases and seven SRP type IV cases. It was not possible to screen DYNC2H1 in two patients due to insufficient amount of DNA.
The study identified homozygous NEK1 mutations in 5/13 SRP type II and compound heterozygous DYNC2H1 mutations in 4/12 cases. Finally, NEK1 and DYNC2H1 were excluded in 3/12 SRP type II and in all SRP type IV cases. The main difference between the mutation positive SRP type II group and the mutation negative SRP type II group was the presence of holoprosencephaly and polymycrogyria in the mutation negative group.
This study confirms that NEK1 is one gene causing SRP type II but also reports mutations in DYNC2H1, expanding the phenotypic spectrum of DYNC2H1 mutations. The exclusion of NEK1 and DYNC2H1 in 3/12 SRP type II and in all SRP type IV cases further support genetic heterogeneity.
Journal of Medical Genetics 04/2012; 49(4):227-33. · 5.70 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive multiple congenital malformation syndrome caused by dehydrocholesterol reductase deficiency. The diagnosis is confirmed by high 7- and secondarily 8-dehydrocholesterol levels in plasma and tissues and/or by detection of biallelic mutations in the DHCR7 gene. The phenotypic spectrum of SLOS is broad, ranging from a mild phenotype combining subtle physical anomalies with behavioral and learning problems, to a perinatally lethal multiple malformations syndrome. The fetal phenotype of SLOS has been poorly described in the literature. We report a series of 10 fetuses with molecularly proven SLOS. Even in young fetuses, the facial dysmorphism appears characteristic. Genital abnormalities are rare in 46,XX subjects. Gonadal differentiation appears histologically normal and in agreement with the chromosomal sex, contrary to what has been previously stated. We observed some previously unreported anomalies: ulnar hypoplasia, vertebral segmentation anomalies, congenital pulmonary adenomatoid malformation, fused lungs, gastroschisis, holomyelia and hypothalamic hamartoma. This latter malformation proves that SLOS phenotypically overlaps with Pallister-Hall syndrome which remains clinically a major differential diagnosis of SLOS.
European journal of medical genetics 02/2012; 55(2):81-90. · 1.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cobblestone lissencephaly represents a peculiar brain malformation with characteristic radiological anomalies, defined as cortical dysplasia combined with dysmyelination, dysplastic cerebellum with cysts and brainstem hypoplasia. Cortical dysplasia results from neuroglial overmigration into the arachnoid space, forming an extracortical layer, responsible for agyria and/or 'cobblestone' brain surface and ventricular enlargement. The underlying mechanism is a disruption of the glia limitans, the outermost layer of the brain. Cobblestone lissencephaly is pathognomonic of a continuum of autosomal recessive diseases with cerebral, ocular and muscular deficits, Walker-Warburg syndrome, muscle-eye-brain and Fukuyama muscular dystrophy. Mutations in POMT1, POMT2, POMGNT1, LARGE, FKTN and FKRP genes attributed these diseases to α-dystroglycanopathies. However, studies have not been able to identify causal mutations in the majority of patients and to establish a clear phenotype/genotype correlation. Therefore, we decided to perform a detailed neuropathological survey and molecular screenings in 65 foetal cases selected on the basis of histopathological criteria. After sequencing the six genes of α-dystroglycanopathies, a causal mutation was observed in 66% of cases. On the basis of a ratio of severity, three subtypes clearly emerged. The most severe, which we called cobblestone lissencephaly A, was linked to mutations in POMT1 (34%), POMT2 (8%) and FKRP (1.5%). The least severe, cobblestone lissencephaly C, was linked to POMGNT1 mutations (18%). An intermediary type, cobblestone lissencephaly B, was linked to LARGE mutations (4.5%) identified for the first time in foetuses. We conclude that cobblestone lissencephaly encompasses three distinct subtypes of cortical malformations with different degrees of neuroglial ectopia into the arachnoid space and cortical plate disorganization regardless of gestational age. In the cerebellum, histopathological changes support the novel hypothesis that abnormal lamination arises from a deficiency in granule cells. Our studies demonstrate the positive impact of histoneuropathology on the identification of α-dystroglycanopathies found in 66% of cases, while with neuroimaging criteria and biological values, mutations are found in 32-50% of patients. Interestingly, our morphological classification was central in the orientation of genetic screening of POMT1, POMT2, POMGNT1, LARGE and FKRP. Despite intensive research, one-third of our cases remained unexplained; suggesting that other genes and/or pathways may be involved. This material offers a rich resource for studies on the affected neurodevelopmental processes of cobblestone lissencephaly and on the identification of other responsible gene(s)/pathway(s).