Altered GLI3 and FGF8 signaling underlies acrocallosal syndrome phenotypes in Kif7 depleted mice.

Acrocallosal syndrome (ACLS) is a rare genetic disorder characterized by agenesis or hypoplasia of corpus callosum (CC), polydactyly, craniofacial dysmorphism and severe intellectual deficiency. We previously identified KIF7, a key ciliary component of the Sonic hedgehog (SHH) pathway, as being a causative gene for this syndrome, thus including ACLS in the group of ciliopathies. In both humans and mice, KIF7 depletion leads to abnormal GLI3 processing and over-activation of SHH target genes. To understand the pathological mechanisms involved in CC defects in this syndrome, we took advantage of a previously described Kif7-/- mouse model to demonstrate that in addition to polydactyly and neural tube closure defects, these mice present CC agenesis with characteristic Probst bundles, thus recapitulating major ACLS features. We show that CC agenesis in these mice is associated with specific patterning defects of the cortical septum boundary leading to altered distribution of guidepost cells required to guide the callosal axons through the midline. Furthermore, by crossing Kif7-/- mice with Gli3Δ699 mice exclusively producing the repressive isoform of GLI3 (GLI3R), we demonstrate that decreased GLI3R signaling is fully responsible for the ACLS features in these mice, as all phenotypes are rescued by increasing GLI3R activity. Moreover, we show that increased FGF8 signaling is responsible in part for CC defects associated to KIF7 depletion, as modulating FGF8 signaling rescued CC formation anteriorly in Kif7-/- mice. Taken together our data demonstrate that ACLS features rely on defective GLI3R and FGF8 signaling.

Intracranial cystic lesions and polydactyly associated with acrocallosal syndrome: Sonographic findings in two cases.

We describe two cases of intracranial cystic lesions associated with acrocallosal syndrome. These fetal anomalies were detected on antenatal sonography and confirmed postnatally. Imaging findings include corpus callosum agenesis with interhemispheric cysts and craniofacial anomalies associated with polydactyly. Identifying the above imaging features is of importance to plan management and provide supportive care that may be required.

A de novo GLI3 mutation in a patient with acrocallosal syndrome.

Acrocallosal syndrome is characterized by postaxial polydactyly, macrocephaly, agenesis of the corpus callosum, and severe developmental delay. In a few patients with this disorder, a mutation in the KIF7 gene has been reported, which was associated with impaired GLI3 processing and dysregulaton of GLI3 transcription factors. A single patient with acrocallosal syndrome and a de novo p.Ala934Pro mutation in GLI3 has been reported, whereas diverse and numerous GLI3 mutations have also been described in syndromes with overlapping clinical manifestations, including Greig cephalopolysyndactyly syndrome, Pallister-Hall syndrome, trigonocephaly with craniosynostosis and polydactyly, oral-facial-digital syndrome, and non-syndromic polydactyly. Here, we describe a second patient with acrocallosal syndrome, who has a de novo, novel c.2786T>C mutation in GLI3, which predicts p.Leu929Pro. This mutation is in the same domain as the mutation in the previously reported patient. These data confirm that mutations in GLI3 are a cause of the acrocallosal phenotype.

Novel KIF7 mutations extend the phenotypic spectrum of acrocallosal syndrome.

BACKGROUND: Acrocallosal syndrome (ACLS) is a rare recessive disorder characterised by corpus callosum agenesis or hypoplasia, craniofacial dysmorphism, duplication of the hallux, postaxial polydactyly, and severe mental retardation. Recently, we identified mutations in KIF7, a key component of the Sonic hedgehog pathway, as being responsible for this syndrome. METHODS: We sequenced KIF7 in five suspected ACLS cases, one fetus and four patients, based on facial dysmorphism and brain anomalies. RESULTS: Seven mutations were identified at the KIF7 locus in these five cases, six of which are novel. We describe the first four compound heterozygous cases. In all patients, the diagnosis was suspected based on the craniofacial features, despite the absence of corpus callosum anomaly in one and of polydactyly in another. Hallux duplication was absent in 4/5 cases. CONCLUSIONS: These results show that ACLS has a variable expressivity and can be diagnosed even in the absence of the two major features, namely polydactyly or agenesis or hypoplasia of the corpus callosum. Facial dysmorphism with hypertelorism and prominent forehead in all the cases, as well as vermis dysgenesis with brainstem anomalies (molar tooth sign), strongly indicated the diagnosis. KIF7 should be tested in less typical patients in whom craniofacial features are suggestive of ACLS.

Cognitive and behavioral functioning in Coffin-Siris syndrome and epilepsy: a case presentation.

The authors characterized the cognitive, adaptive, and behavioral sequelae of Coffin-Siris (CS) syndrome and epilepsy in a 7.5-year-old child. Little is known about the early neurobehavioral presentation of CS. Clinical features consistent with this genetic anomaly include underdeveloped tips and nails of the fifth fingers, extended infranasal depression, and craniofacial abnormalities. MRI findings often reveal callosal agenesis. The authors conducted a neuropsychological evaluation and obtained parental ratings of behavioral and adaptive functioning. Attentional abilities were limited. As assessed by the Mullen Scales of Early Learning, receptive language abilities (age equivalent [AE]: 3-3) were relatively stronger than expressive skills (AE: 1-4). Adaptive functioning was low across all domains (Vineland Adaptive Behavior Composite AE: 1-9). On the Behavior Assessment for Children (BASC-2), social skills dysfunction, stereotyped and self-stimulatory behaviors, restricted interests, ritualistic play, and inappropriate object usage were noted. No significant mood disturbances were endorsed. Study findings indicate a diffuse pattern of neurobehavioral deficits in a child with CS and epilepsy. Further clinical assessment and research should include multidimensional assessment techniques, including evaluation of adaptive behavior, in an effort to capture the full range developmental sequelae in children with CS.

The FG syndrome from a pathological perspective.

We report on a case of FG syndrome in an almost 6-year-old boy, diagnosed post-mortem. The description of the intellectual and behavior phenotype provided by the mother, together with the evidence gathered at autopsy, were sufficient to reach a clinical diagnosis. The mother had mild manifestations, including a symptomatic tethered cord, which established her as a carrier of the putative mutation causing the syndrome in the son. The propositus' phenotype did not suggest involvement of the MED12 gene.

Absence of the anterior fontanelle due to a fontanellar bone.

Improved accessibility to supraregional centers in the United Kingdom has led to an increased referral of minor craniofacial anomalies. We have recognized a group of patients referred with absence of the anterior fontanelle and possible associated craniosynostosis. The aim of this study was to assess the group of patients in which the anterior fontanelle was entirely replaced by a single bone, examining associations, relationship to craniosynostosis, and prognostic implications.Eleven patients had fontanellar bones replacing the anterior fontanelle on computed tomographic imaging in the 3-year study period. Five were referred solely because of absence of the anterior fontanelle; and the remainder, because of concern of concomitant craniosynostosis. Five children had associated craniosynostosis (sagittal synostosis, 3; metopic synostosis, 1; and bicoronal synostosis, 1), 1 had acrocallosal syndrome, and 5 had no other craniofacial abnormalities. The patient group with craniosynostosis have been managed in line with the unit protocol and have good early postoperative results (mean postoperative follow-up, 9.4 mo). The 5 patients who had an anterior fontanellar bone as an isolated finding were observed and have developed normally with a mean follow-up of 2 years 1.4 months (range, 8 mo to 3 y 4 mo).Replacement of the anterior fontanelle with a fontanellar bone is an uncommon finding, often associated with craniosynostosis. Cases with craniosynostosis can be treated in line with unit protocols. Isolated anterior fontanellar bones can be managed conservatively without adverse impact on the child.

Ocular findings in pediatric patients with partial agenesis of corpus callosum.

PURPOSE: To evaluate the ocular associations with corpus callosum agenesis. METHODS: All children who had corpus callosum agenesis diagnosed by computed tomography or magnetic resonance imaging scans during a 10-year period were included in the study. A complete ophthalmological assessment was undertaken. Data were collected for age, sex, neurological findings, visual acuity, refractive errors, ocular motility defects, and ocular abnormalities. There were no children with Aicardi syndrome in the study. RESULTS: Nineteen children with corpus callosum agenesis were identified, of whom 13 were examined. All had partial agenesis of the corpus callosum. Visual acuity was better than 20/60 in 5 children (38%), between 20/60 and 20/200 in 3 children (23%), and less than 20/200 in 5 children (38%). Refractive errors were present in 8 children (62%), strabismus in 6 children (46%), nystagmus in 2 children (15%), hypoplastic discs in 3 children (23%), and microphthalmos in 1 child (8%). CONCLUSION: Non-syndromic corpus callosum agenesis may be associated with several ocular defects. Poor visual acuity, refractive errors, and strabismus predominate and need to be appropriately addressed to optimize visual function in these children. Global developmental delay (62%) and epilepsy (46%) were the most common neurological associations in this series.

Neurological and psychiatric aspects of corpus callosum genesis.

This article reports the case of a patient with partial agenesis of the corpus callosum manifested with corpus callosum syndrome together with signs of brain hemispheres dysfunction: mental impairment, epilepsy and pyramidal signs. The patient's malformation is combined with left-handedness while signs of callosal disconnection are not present. Mild cognitive impairment and late epilepsy onset require a multidisciplinary approach since the patient also displays elements of central nervous system malformations.

[Agenesis of corpus callosum - a review].

The subject herein discussed is malformations about which information abounds. This is due to constant improvements in approaches to obtaining such information through images generated by modern imaging technology. As the examination of structures at hand progresses, so does the possibility for precise imaging diagnostics. Agenesis of the corpus callosum is one those subtle and difficult to detect malformations which are currently becoming subjects of research. Agenesis of the corpus callosum is a brain anomaly with incidence of occurrence from 0.05 to 0.7%. It could be either observed in 49% of cases unaccompanied by other conditions or accompanied by other anomaly syndromes. This cerebral malformation is usually diagnosed post partum in children suffering from epilepsy or behaviour or cognitive disorders. In consideration of the necessity of early fetal abnormality detection and the conduct of the obstetrician in a social aspect, the above-mentioned is a prerequisite which makes discussions necessary. Constant up-dating and discussions allow periodic revision and optimizations of prenatal diagnostics.

Toriello-Carey syndrome in a Turkish newborn.

Toriello-Carey syndrome in a Turkish newborn: Toriello-Carey syndrome is characterized by agenesis of the corpus callosum, telecanthus, short palpebral fissures, small nose with anteverted nares, retrognathia, abnormal ears, laryngeal and cardiac anomalies, brachydactyly, and hypotonia. We describe the findings in a Turkish newborn, presumed to be another example of the Toriello-Carey syndrome, which extends the phenotype of the syndrome.

Hyperekplexia in a neonate: a novel finding in Fukuyama type congenital muscular dystrophy.

The Fukuyama type congenital muscular dystrophy (FCMD) is a rare autosomal recessive disorder characterized by cranial, cerebellar and ocular malformations and congenital muscular dystrophy. Hyperekplexia is characterized by transient, generalized rigidity in response to unexpected loud noises or sudden tactile stimulation. Herein, we report an infant who had typical clinical features of FCMD with hyperekplexia. Our purpose is to draw attention to this first report of concomitant FCMD and hyperekplexia.

Physical, motor, sensory and developmental features associated with agenesis of the corpus callosum.

BACKGROUND: The study objective was to develop a profile of characteristics and diagnostic indicators of agenesis of the corpus callosum (ACC) using a large sample of individuals with ACC and their siblings. Very few previous studies have been able to access large populations in order to develop a comprehensive profile. METHODS: Caregivers of 720 individuals with ACC and 219 siblings, the largest sample studied to date, provided surveys with data on diagnoses, physical characteristics, developmental patterns and physical functioning. RESULTS: Compared with siblings, individuals with ACC exhibited a pattern of delayed motor development, difficulty with balance and bimanual movements, large head size, poor muscle tone, poor depth perception, reduced pain perception, sleeping difficulties and an increased proportion of left and mixed handedness. CONCLUSIONS: These results extend previous descriptions but are also consistent with published reports that used small samples and single case studies. The data provide a profile that has implications for early detection and intervention of individuals with ACC as well as for highlighting future research directions to extend knowledge about ACC.

Consideration of median cleft lip with frenulum labii superior.

Median cleft lip is usually divided into true and false when being discussed. Owing to recent developments of diagnostic imaging methods that have improved the accuracy, the presence of an intermediate type of median cleft lip, which cannot simply be divided into true and false, has been suggested. However, the simple method of classification is still clinically valuable. We have previously reported in this Journal a case of median cleft lip with 2 upper labial frenums. In the present study, based on our experience with false median cleft lip, we set forth a hypothesis that 2 upper labial frenums can be found in true median cleft lip, whereas no upper labial frenum is found in false median cleft lip. A review of the results of previous Japanese cases (7 true and 4 false cases) supported our hypothesis. We also reviewed one of our cases of right cleft lip accompanied by holoprosencephaly and discuss the case from the developmental perspective. The shape of the upper labial frenum may be a factor that can be used for clinically classifying intermediate median cleft lip into either true or false in cases that are otherwise difficult to classify.

[Acrocallosal syndrome without psychomotor abnormality: a case report]. / Syndrome acro-calleux sans retard mental: à propos d'un cas.

We report a case of acrocallosal syndrome in a 7-month-old female patient born to consanguineous parents, who presented with agenesis of the corpus callosum, polydactyly, and minor craniofacial dysmorphism. This case is similar to two other occurrences described in the literature, with no psychomotor development delay and hypotonia.

Commissural malformations: beyond the corpus callosum.

Corpus callosum agenesis is frequently only the tip of the iceberg in midline commissural anomalies. Agenesis or hypogenesis of the remaining commissures including the anterior and hippocampal commissures should be excluded. Magnetic resonance imaging is the most sensitive imaging modality to identify commissural anomalies. Diffusion tensor imaging can be helpful to identify hypogenetic or absent commissures even in the preterm neonate.

Acrocallosal syndrome in a young hypertensive male.

Acrocallosal syndrome is an extremely rare genetic disorder with autosomal recessive inheritance. It is characterised by moderate to severe mental retardation, hypotonia, agenesis of the corpus callosum and preaxial polydactyly involving both feet and the facial features like broad forehead and hypertelorism. The authors report a case of a young hypertensive male who presented with unprovoked seizures for the first time who had multiple craniofacial, digital dysmorphic features with moderate mental retardation. The diagnosis of acrocallosal syndrome was arrived at after neuroimaging showed agenesis of corpus callosum with interhemispheric cysts.

[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.