Bilateral Perisylvian Polymicrogyria Research Articles

X-linked malformations of cortical development.

Disorders of the development of the human cortex are recognized as significant causes of mental retardation, epilepsy, and congenital neurologic deficits. These malformations may be restricted to the brain or may be one component of a generalized malformation syndrome. Through the efforts of several groups, a large number of human cortical malformations have been identified and classified. Studies of informative families and sporadic patients with specific chromosomal rearrangements or deletions have demonstrated a genetic basis for many of these disorders. Subsequent work has facilitated a precise genetic diagnosis and provided insight into the molecular basis of some of these malformations. This review will discuss four cortical malformation syndromes, which are known or likely to have an X-linked inheritance pattern: bilateral periventricular nodular heterotopia, X-linked lissencephaly/subcortical band heterotopia, X-linked lissencephaly with abnormal genitalia, and X-linked bilateral perisylvian polymicrogyria.

Bilateral perisylvian polymicrogyria in three generations.

A family is described in which bilateral perisylvian polymicrogyria was present in 6 members of 3 consecutive generations. Typical anatomic and clinical findings of the syndrome, with a mild phenotype, were present in the 5 affected women from all 3 generations. More severe impairment was observed in the only affected male individual, a boy, in the third generation. Analysis of the pedigree and severity of the phenotype in the affected boy are consistent with transmission of an X-linked dominant trait, although other patterns of inheritance cannot be ruled out with certainty.

Regional Cerebral Blood Flow in Patients with Cerebral Cortical Malformations and Intractable Partial Seizures

Purpose: Changes of regional cerebral blood flow (rCBF) in patients with epilepsy with cerebral cortical malformations (CCMs) were studied interictally and ictally, and compared with rCBF in patients with other epileptogenic lesions. Methods: The interictal and ictal rCBF of 66 patients with medically intractable partial seizures with CCMs, identified by magnetic resonance imaging (MRI; 63 cases) or histological study of surgically resected specimens (33 cases) or both were measured by using single photon emission computed tomography (SPECT). The CCMs were classified into cortical dysplasia in 40 patients (34 intralobular and six multilobular), heterotopia in 16 patients (seven double cortex, six sub‐cortical, and three periventricular/subependymal), polymicrogyria in six patients (two bilateral perisylvian polymicrogyria, two unilateral schizencephaly, and two focal polygyric anomaly), hemimegalencephaly in two patients, and pachygyria in two patients. Among the 63 patients with symptomatic partial epilepsy, the localization of their epileptogenic foci was identified in 54 patients (26 frontal, 14 temporal, five occipital, two parietal, and seven multilobular) according to further electroclinical investigation. Three patients with undetermined epilepsies had both partial and generalized seizures. The rCBF‐SPECT findings on static images were evaluated according to the following gradings: hypoperfusion, hyperperfusion, and no remarkable changes. These findings with CCM were compared with those in 59 patients with benign tumors, 10 with angiomas and 117 with medial temporal sclerosis (MTS). Results: Interictal hypoperfusion was recognized in 33 (50%) patients with CCMs, in 86 (73%) with MTS, in 40 (68%) with benign tumors, and in five (50%) with angiomas. Interictal hyperperfusion was seen only in 11 (17%) patients with CCM. Among the 66 patients with CCMs, interictal hypoperfusion was detected in 27 (67%) of 40 cases with cortical dysplasia, in two of two with hemimegalencephaly, and in one of two with pachygyria. In contrast, interictal hypoperfusion was detected only in three (19%) of 16 cases with heterotopia and in none with polymicrogyria. Interictal hyperperfusion was recognized in four patients with heterotopia, in four with polymicrogyria, in two with cortical dysplasia, and in one with pachygyria. An ictal study was performed in 36 patients with CCMs. Increased rCBF at the ictal stage was recognized in 74%, but there was no definite correlation with the different kinds of CCM. Conclusions: Compared with that of other epileptogenic lesions, the frequency of detection of interictal hypoperfusion with SPECT in CCMs is lower, but interictal hyperperfusion was recognized only in CCMs. Moreover, we found some differences concerning the interictal CBF findings between heterotopia/polymicrogyria caused by abnormal neuronal migration and cortical dysplasia caused by abnormal organization. These results suggest that etiology and pathogenesis of CCMs are factors affecting rCBF and revealed that rCBF‐SPECT is effective for detecting the changes of interictal and ictal rCBF closely related to epileptogenesis in patients with CCMs.

Pediatric congenital bilateral perisylvian syndrome: clinical and MRI features in 12 patients.

In 1926, Foix, Chavany and Marie described an acquired syndrome of fasciopharyngoglossomasticatory diplegia resulting from bilateral infarction of the anterior operculum. Clinical features consisted of facial diplegia, dysarthria, pseudobulbar palsy, mild to severe mental retardation, and seizures. A developmental form, similar in presentation in adults with MRI findings consisting of bilateral perisylvian cortical malformation consistent with polymicrogyria involving the sylvian fissure and opercular cortex, has been recognized; but few pediatric cases of congenital bilateral perisylvian syndrome (CBPS) have been reported. Over the past four years, we have encountered 12 cases of CBPS presenting in childhood. Age ranges were from 1 week to 11 years with a median of 2.25 years; six were less than two years of age. Seven were male and five female. Ten had bilateral perisylvian polymicrogyria on MRI; two had unilateral perisylvian schizencephaly with contralateral perisylvian polymicrogyria. Clinical manifestations included developmental delay in 7; poor palatal function in 5; hypotonia in 4; arthrogryposis in 4; hemiparesis in 3; apnea in 3; paraparesis in 2; micrognathia in 2; pectus excavatum in 2; quadriparesis in 1; and hearing loss in 1. Seizures occurred in seven (58%) and consisted of infantile spasms (n = 1), generalized tonic-clonic (n = 1), complex partial (n = 2), partial motor (n = 2; 1 with secondary generalization), and febrile convulsions (n = 1). CBPS has different manifestations in the pediatric population than in adults. CBPS is more common than previously thought, is recognizable by MRI and should be suspected clinically in any infant or child presenting with oromotor dysfunction/pseudobulbar signs and developmental delay, especially if there are associated congenital malformations. Epilepsy is not a constant feature in the pediatric presentation and is variable in type and severity.

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Malformations of cortical development (MCD) represent a major cause of developmental disabilities and severe epilepsy. Advances in imaging and genetics have improved the diagnosis and classification of these conditions. Up to now, eight genes have been involved in different types of MCD. Lissencephaly-pachygyria and subcortical band heterotopia (SBH) represent a malformative spectrum resulting from mutations of either LIS1 or DCX genes. LIS1 mutations cause a more severe malformation in the posterior brain regions. DCX mutations usually cause anteriorly predominant lissencephaly in males and SBH in female patients. Additional forms are X-linked lissencephaly with corpus callosum agenesis and ambiguous genitalia associated with mutations of the ARX gene. Lissencephaly with cerebellar hypoplasia (LCH) encompass heterogeneous disorders named LCH types a to d. LCHa is related to mutation in LIS1 or DCX, LCHb with mutation of the RELN gene, and LCHd could be related to the TUBA1A gene.Polymicrogyria encompasses a wide range of clinical, etiological, and histological findings. Among several syndromes, recessive bilateral fronto-parietal polymicrogyria has been associated with mutations of the GPR56 gene. Bilateral perisylvian polymicrogyria has been associated with mutations in the SRPX2 gene in a few individuals and with linkage to chromosome Xq28 in a some other families.X-linked bilateral periventricular nodular heterotopia (PNH) consists of PNH with focal epilepsy in females and prenatal lethality in males. Filamin A (FLNA) mutations have been reported in some families and in sporadic patients. It is possible to infer the most likely causative gene by brain imaging studies and other clinical findings.

The epileptic spectrum in the congenital bilateral perisylvian syndrome. CBPS Multicenter Collaborative Study.

We studied the frequency, clinical and EEG characteristics, and outcome of the epileptic syndrome in 31 patients with a congenital neurologic syndrome characterized by pseudobulbar palsy, cognitive deficits, and bilateral perisylvian polymicrogyria. Seizures were present in 27 of 31 patients (87%) and usually began between the ages of 4 and 12 years; they commonly consisted of atypical absence, atonic/tonic, and generalized tonic-clonic seizures. Partial attacks were present in 26%. EEG demonstrated generalized spike and wave abnormalities and, less frequently, multifocal discharges, predominantly in centro-parietal regions. Seizures were poorly controlled in 65%, with the remaining patients well controlled. Seven patients underwent callosotomy, which resulted in seizure improvement. This study indicates that the epileptic spectrum in this syndrome is broad but follows predictable patterns. Callosotomy is a valuable treatment strategy in those with intractable drop attacks.