Spectrum of corpus callosum agenesis

Magnetic resonance imaging and clinical features of 16 children with agenesis of the corpus callosum are reviewed. The patients were classified in three groups. Eight children had agenesis of the corpus callosum without substantial involvement of other brain areas. This group included patients with interhemispheric cyst, lipoma, or partial agenesis (hypogenesis) of the corpus callosum. Four patients in the second group manifested severe telencephalic dysgenesis in addition to agenesis of the corpus callosum. In the third group, agenesis of the corpus callosum was a component of a syndrome in four children. The outcome was not favorable for the majority of patients, even in the first group without significant involvement of other systems. Severe handicaps with developmental delay, intellectual disability, and neurologic deficit were observed in patients with additional telencephalic dysgenesis or syndromic form of corpus callosum agenesis.     

Transcallosal resection of hypothalamic hamartoma for gelastic epilepsy

Introduction Hypothalamic hamartomas (HHs) are commonly associated with severe epilepsy resistant to anticonvulsant therapy. Historically, surgical resection of HHs resulted in considerable morbidity. Discussion Two series of patients who successfully underwent resection using a transcallosal approach have now been published; we report the first UK experience of this technique in a series of five patients with HHs and gelastic epilepsy resistant to anticonvulsant therapy. Patients were assessed pre- and postoperatively for seizure activity, endocrine function, ophthalmology, and neurocognitive function. Two patients had precocious puberty and all had evidence of developmental delay and behavioral problems. Postoperatively, all children experienced at least a 50% reduction in seizure frequency with abolition of major seizure types; one child remains seizure-free. One child developed a mild postoperative right hemiparesis and one developed transient diabetes insipidus. Conclusion There were no adverse developmental effects of surgery. Transcallosal resection of HHs ameliorates resistant epilepsy syndromes associated with HH.     

Episodic hyperhidrosis, hypothermia, and agenesis of corpus callosum

Episodic hyperhidrosis and hypothermia are the primary symptoms of a rare central nervous system disorder of thermoregulation which is often associated with agenesis of the corpus callosum and can present in childhood or adult years. During attacks, patients may exhibit confused, withdrawn, and lethargic behavior and ataxia or other neurologic symptoms. A 21-year-old man with temperature chronically between 30 and 32 degrees C transiently responded to phenobarbital and to cyproheptadine therapy. A 34-year-old woman with frequent, brief episodes of hypothermia and hyperhidrosis improved with chlorpromazine treatment. Episodic thermoregulatory disturbance has been attributed to "vagal attacks" or "diencephalic epilepsy," but the pathophysiology remains undefined.     

Partial agenesis of the corpus callosum in a patient with juvenile myoclonic epilepsy.

We describe a patient who presented at our epilepsy-monitoring unit with myoclonic jerks, and was diagnosed with juvenile myoclonic epilepsy (JME). Imaging of his brain revealed partial agenesis of the corpus callosum (ACC). We discuss the known genetic basis of both JME and ACC, as well as the role of the corpus callosum (CC) in primary generalized epilepsy. Both JME and ACC are associated with gene loci on chromosome 15q14. Structural brain abnormalities other than ACC, such as atrophy of the corpus callosum have been reported in patients with JME. ACC has been associated with seizures, suggesting an anti-epileptogenic role of the corpus callosum. On the other hand, corpus callosotomy is used to treat refractory idiopathic generalized epilepsy, which shows that the corpus callosum may play an epileptogenic role. The occurrence of both these conditions in one patient raises the question of whether they are purely coincidental or if there is a common basis for both. Several issues need to be addressed: the mechanism of seizure generalization in the setting of partial ACC, the possible role of other structures in generalization, and whether the ACC contributes to epileptogenesis as a result of the lack of a normal CC inhibitory effect.     

Hypothalamic hamartoma,gelastic epilepsy,precocious puberty--a diffuse cerebral dysgenesis

Childhood epileptic syndrome characterized by early onset gelastic seizures, hypothalamic hamartoma and precocious puberty is well recognized though rare. We report association of agenesis of corpus callosum, Dandy–Walker complex and heterotopic gray matter with this childhood epileptic syndrome which is hitherto an unreported association. The child showed a satisfactory response to gonadotropin releasing hormone agonist.     

Alexithymia and somatization in agenesis of the corpus callosum

Deficient communication between the cerebral hemispheres is one of several prevailing neurobiological explanations for alexithymia and has been strongly supported by research on patients with commissurotomy. We examined self-reported symptoms of alexithymia in adults with agenesis of the corpus callosum (AgCC), a condition characterized by more subtle reductions in interhemispheric transfer than in commissurotomy. Sixteen adults with AgCC and full-scale intelligence quotient >80 were compared with 15 neurotypical controls group-matched for age and intelligence score. The AgCC group endorsed greater difficulty identifying and describing feelings and more vague physical symptoms than controls but similar levels of emotional experience and emotional coping. This finding of impaired emotional interpretation with intact emotional experience is consistent with findings in callosotomy patients, implicating the critical role of the corpus callosum in cognitive dimensions of emotion processing. Further study of alexithymia in AgCC using task-based measures may help clarify the nature of this relationship.     

Facial emotion recognition in agenesis of the corpus callosum

Background

Impaired social functioning is a common symptom of individuals with developmental disruptions in callosal connectivity. Among these developmental conditions, agenesis of the corpus callosum provides the most extreme and clearly identifiable example of callosal disconnection. To date, deficits in nonliteral language comprehension, humor, theory of mind, and social reasoning have been documented in agenesis of the corpus callosum. Here, we examined a basic social ability as yet not investigated in this population: recognition of facial emotion and its association with social gaze.

Methods

Nine individuals with callosal agenesis and nine matched controls completed four tasks involving emotional faces: emotion recognition from upright and inverted faces, gender recognition, and passive viewing. Eye-tracking data were collected concurrently on all four tasks and analyzed according to designated facial regions of interest.

Results

Individuals with callosal agenesis exhibited impairments in recognizing emotions from upright faces, in particular lower accuracy for fear and anger, and these impairments were directly associated with diminished attention to the eye region. The callosal agenesis group exhibited greater consistency in emotion recognition across conditions (upright vs. inverted), with poorest performance for fear identification in both conditions. The callosal agenesis group also had atypical facial scanning (lower fractional dwell time in the eye region) during gender naming and passive viewing of faces, but they did not differ from controls on gender naming performance. The pattern of results did not differ when taking into account full-scale intelligence quotient or presence of autism spectrum symptoms.

Conclusions

Agenesis of the corpus callosum results in a pattern of atypical facial scanning characterized by diminished attention to the eyes. This pattern suggests that reduced callosal connectivity may contribute to the development and maintenance of emotion processing deficits involving reduced attention to others'' eyes.     

Magnetic resonance imaging in agenesis of the corpus callosum

The recent use of computed tomography (CT) scan is providing an easy diagnoses of agenesis of corpus callosum which had been difficult to diagnose only by clinical signs and symptoms. Since, more neuropsychological studies on agenesis of corpus callosum are being done, clinical details of agenesis of corpus callosum are being clarified. We examined magnetic resonance imaging (MRI) on 3 patients who were suspected to have agenesis of corpus callosum by CT scan. And we studied the usefulness of MRI in agenesis of corpus callosum. Case 1. We studied a thirty-two-year-old right-handed man with a one-year history of amyotrophic lateral sclerosis. He had no callosal disconnection syndrome. CT scan on horizontal view showed dilated third ventricle, the dilatation of the occipital horns and wide separation of the lateral ventricles. On coronal view, CT scan showed the absence of the corpus callosum, the concave mesial borders of the lateral ventricle, the dilatation of the third ventricle and its abnormal dorsal extent(bat-wing appearance). On sagittal MRI (the inversion recovery technique), the corpus callosum was absent and the convolutions and sulci were arranged radically centering the third ventricle (radial distribution). But the anterior commissure was preserved. Case 2. We studied a fourty-one-year-old right-handed man with a seven-year history of hyper ventilation syndrome. He had no callosal disconnection syndrome. CT scan showed the similar findings as those of case 1. On sagittal MRI (the inversion recovery technique), the corpus callosum was absent, and the convolutions and sulci showed radial distribution. But the anterior commissure was preserved.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical and diagnostic profile of agenesis of the corpus callosum

This study reports the clinical profile, etiologies identified, and outcomes for a consecutive series of children with partial or complete agenesis of the corpus callosum. Children with agenesis of the corpus callosum were identified in a comprehensive computerized database of all patients seen in a single pediatric neurology practice over an 11-year interval. Medical records were then systematically reviewed. Twenty-four children with agenesis of the corpus callosum were identified of a total of 6911 children in the database (0.35%). Fifteen were male (62.5%); 9 (37.5%) had presented antenatally, 6 (25%) neonatally, and 9 (37.5%) postneonatally. Eight (33.3%) were microcephalic, 12 (50%) were dysmorphic, 11 (45.8%) had coexisting epilepsy, and 9 (37.5%) had a cerebral palsy variant. Investigations revealed an etiology in 11 (45.8%): 3 chromosomal abnormality, 3 metabolic disorder, 3 cerebral dysgenesis, and 2 genetic syndromes (Aicardi, Andermann). Outcomes identified included normal or mild developmental delay in 7 (29.2%) and moderate-severe developmental delay in the remaining 17 (70.8%). Factors predictive of successful etiologic determination on bivariate analysis included moderate-severe developmental delay or associated cerebral dysgenesis. Factors predictive of eventual developmental outcome included microcephaly, coexisting epilepsy, cerebral palsy, or cerebral dysgenesis. A spectrum of clinical presentations, underlying etiology, and developmental outcome is thus apparent in children with agenesis of the corpus callosum. An underlying etiology can be identified in slightly less than half of cases, and a normal or mildly delayed outcome is apparent in slightly less than a third. Factors predictive of identifying an underlying etiology or eventual outcome can be identified.     

Unilateral photoconvulsive response in agenesis of the corpus callosum

An 11-year-old female presented with the unusual coexistence of self-induced photogenic epilepsy and an atypical epileptiform ictal EEG pattern evoked by intermittent photic stimulation. The EEG showed irregular 2.5-4 Hz spike-wave and polyspike-wave complexes, strictly localized on the left hemisphere, and associated with impairment of consciousness and myoclonic jerking of the contralateral side of the body. A computer tomographic scan showed agenesis of the corpus callosum. According to the literature on corpus callosum section in uncontrolled epilepsies, we hypothesize that in our patient the agenesis of the corpus callosum probably prevented the generalization of the ictal EEG pattern evoked by intermittent photic stimulation.     

Clinicopathological findings associated with agenesis of the corpus callosum

Seven hundred five cases of agenesis of the corpus callosum (ACC) are reviewed from the literature (n = 660) and from our own observations (n = 45). The diagnosis was made or confirmed using neuroradiological techniques (n = 519) and necropsy or surgery (n = 231). Association with abnormalities often of chromosomes 8, 11, 13-15 and 18 suggests their involvement in abnormal corpus callosum (CC) morphogenesis. Four syndromes (e.g. Aicardi, acrocallosal, Andermann and Shapiro) are characterized by ACC, while others are only sporadically associated (e.g. fetal alcohol syndrome, Dandy-Walker syndrome, Leigh disease, Arnold-Chiari II syndrome). In non-Aicardi patients, the male-to-female ratio was 3:2 and X-linked recessive inheritance is postulated to play a role in some cases. Common abnormalities in acallosal patients included: mental retardation (MR), 73% [corrected]; seizures, 42%; ocular anomalies, 42%; gyral abnormalities, 32%; hydrocephalus, 23%; other central nervous system (CNS) lesions, 29%; costovertebral defects, 24%. Developmental disabilities are not attributable to absence of the CC per se, but due to other CNS malformation or dysfunction, which may be genetic or non-genetic. Future research using recombinant DNA techniques will enable isolation and identification of specific chromosomal defects in those cases with a genetic abnormality.     

Congenital asymmetric crying facies and agenesis of corpus callosum

Although association of congenital asymmetric crying facies (CACF) with major congenital anomalies of central nervous system (CNS) has been described, brain magnetic resonance imaging (MRI) studies have not been reported. Two children who had CACF associated with agenesis of corpus callosum (ACC) diagnosed by MRI are described. Neurofibromatosis type 1 (NF-1) was diagnosed in one case. Both patients had developmental delay. To the best of our knowledge, only one previous case with CACF associated with ACC has been reported, but our cases are the first cases reported with the characteristic findings of ACC on MRI. Although café-au-lait spots have been described in previous cases, the coexistence of CACF and NF-1 has not previously been reported. Although these associations may be coincidental, clinicians should be aware of the potential link between these entities. Furthermore, these findings emphasize the importance of MRI studies for detecting brain anomalies in cases with CACF and suspected CNS involvement.     

Diencephalic epilepsy in a patient with agenesis of the corpus callosum confirmed by computerised axial tomography

A case of diencephalic epilepsy is described in whom stereotyped attacks of spontaneous hypothermia and diaphoresis occurred over a 20 year period. No abnormality of the hypothalamo-pituitary-adrenal axis was found, and there was no evidence of an intracranial mass lesion. Pneumoencephalography and computerised axial tomography (EMI scan) demonstrated agenesis of the corpus callosum.