Background and objectives: Neurologic involvement is the most threatening complication of diarrhea-associated hemolytic uremic syndrome (D+HUS). Design, setting, participants, & measurements: We report a retrospective multicenter series of 52 patients with severe initial neurologic involvement that occurred in the course of D+HUS. Results: Verotoxigenic Escherichia coli infection was documented in 24. All except two patients had acute renal failure that required peritoneal dialysis, hemodialysis, or both techniques. A first group of eight patients remained with normal consciousness; five of them had protracted seizures. A second group of 23 patients had stuporous coma; five of these had protracted severe seizures, and 18 had a neurologic defect including pyramidal syndrome, hemiplegia or hemiparesia, and extrapyramidal syndrome. A third group of 21 patients had severe coma. Plasma exchanges were undertaken in 25 patients, 11 of whom were treated within 24 hours after the first neurologic sign; four died, two survived with severe sequelae, and five were alive without neurologic defect. Magnetic resonance imaging (MRI) for 29 patients showed that (1) every structure of the central nervous system was susceptible to involvement; (2) no correlation seemed to exist between special profile of localization on early MRI and the final prognosis; and (3) MRI did not exhibit any focal lesions in three patients. The overall prognosis of the series was marked by the death of nine patients and severe sequelae in 13. Conclusions: Neurologic involvement is associated with a severe renal disease but does not lead systematically to death or severe disability.

GPR56 mutations cause an autosomal recessive polymicrogyria syndrome that has distinctive radiological features combining bilateral frontoparietal polymicrogyria, white matter abnormalities and cerebellar hypoplasia. Recent investigations of a GPR56 knockout mouse model suggest that bilateral bifrontoparietal polymicrogyria shares some features of the cobblestone brain malformation and demonstrate that loss of GPR56 leads to a dysregulation of the maintenance of the pial basement membrane integrity in the forebrain and the rostral cerebellum. In light of these findings and other data in the literature, this study aimed to refine the clinical features with the first description of a foetopathological case and to define the range of cobblestone-like features in GPR56 bilateral bifrontoparietal polymicrogyria in a sample of 14 patients. We identified homozygous GPR56 mutations in 14 patients from eight consanguineous families with typical bilateral bifrontoparietal polymicrogyria and in one foetal case, out of 30 patients with bifrontoparietal polymicrogyria referred for molecular screening. The foetal case, which was terminated at 35 weeks of gestation in view of suspicion of Walker Warburg syndrome, showed a cobblestone-like lissencephaly with a succession of normal, polymicrogyric and ‘cobblestone-like’ cortex with ectopic neuronal overmigration, agenesis of the cerebellar vermis and hypoplastic cerebellar hemispheres with additional neuronal overmigration in the pons and the cerebellar cortex. The 14 patients with GPR56 mutations (median 8.25 years, range 1.5–33 years) were phenotypically homogeneous with a distinctive clinical course characterized by pseudomyopathic behaviour at onset that subsequently evolved into severe mental and motor retardation. Generalized seizures (12/14) occurred later with onset ranging from 2.5 to 10 years with consistent electroencephalogram findings of predominantly anterior bursts of low amplitude α-like activity. Neuroimaging demonstrated a common phenotype with bilateral frontoparietally predominant polymicrogyria (13/13), cerebellar dysplasia with cysts mainly affecting the superior vermis (11/13) and patchy to diffuse myelination abnormalities (13/13). Additionally, the white matter abnormalities showed a peculiar evolution from severe hypomyelination at 4 months to patchy lesions later in childhood. Taken as a whole, these observations collectively demonstrate that GPR56 bilateral bifrontoparietal polymicrogyria combines all the features of a cobblestone-like lissencephaly and also suggest that GRP56-related defects produce a phenotypic continuum ranging from bilateral bifrontoparietal polymicrogyria to cobblestone-like lissencephaly.

BACKGROUND AND PURPOSE: Waardenburg syndrome, characterized by deafness and pigmentation abnormalities, is clinically and genetically heterogeneous, consisting of 4 distinct subtypes and involving several genes. SOX10 mutations have been found both in types 2 and 4 Waardenburg syndrome and neurologic variants. The purpose of this study was to evaluate both the full spectrum and relative frequencies of inner ear malformations in these patients. MATERIALS AND METHODS: Fifteen patients with Waardenburg syndrome and different SOX10 mutations were studied retrospectively. Imaging was performed between February 2000 and March 2010 for cochlear implant work-up, diagnosis of hearing loss, and/or evaluation of neurologic impairment. Eleven patients had both CT and MR imaging examinations, 3 had MR imaging only, and 1 had CT only. RESULTS: Temporal bone abnormalities were bilateral. The most frequent pattern associated agenesis or hypoplasia of ≥1 semicircular canal, an enlarged vestibule, and a cochlea with a reduced size and occasionally an abnormal shape, but with normal partition in the 13/15 cases that could be analyzed. Three patients lacked a cochlear nerve, bilaterally in 2 patients. In addition, associated abnormalities were found when adequate MR imaging sequences were available: agenesis of the olfactory bulbs (7/8), hypoplastic or absent lacrimal glands (11/14), hypoplastic parotid glands (12/14), and white matter signal anomalies (7/13). CONCLUSIONS: In the appropriate clinical context, bilateral agenesis or hypoplasia of the semicircular canals or both, associated with an enlarged vestibule and a cochlear deformity, strongly suggests a diagnosis of Waardenburg syndrome linked to a SOX10 mutation.

Objective: To determine the spectrum of clinical, neuropsychological, and neuroradiologic features in patients with autosomal recessive primary microcephaly (MCPH) due to ASPM gene mutations. Methods:ASPM was sequenced in 52 unrelated MCPH probands. In patients with ASPM mutations, we evaluated the clinical phenotype, cognition, behavior, brain MRI, and family. Results: We found homozygous or compound heterozygous ASPM loss-of-function mutations in 11 (22%) probands and 5 siblings. The probands harbored 18 different mutations, of which 16 were new. Microcephaly was severe after 1 year of age in all 16 patients, although in 4 patients the occipital-frontal circumference (OFC) at birth was decreased by only 2 SD. The OFC Z score consistently decreased after birth. Late-onset seizures occurred in 3 patients and significant pyramidal tract involvement in 1 patient. Intellectual quotients ranged from borderline-normal to severe mental retardation. Mild motor delay was noted in 7/16 patients. Language development was delayed in all patients older than 3 years. Brain MRI (n = 12) showed a simplified gyral pattern in 9 patients and several malformations including ventricle enlargement (n = 7), partial corpus callosum agenesis (n = 3), mild cerebellar hypoplasia (n = 1), focal cortical dysplasia (n = 1), and unilateral polymicrogyria (n = 1). Non-neurologic abnormalities consisted of short stature (n = 1), idiopathic premature puberty (n = 1), and renal dysplasia (n = 1). Conclusions: We provide a detailed description of features associated with ASPM mutations. Borderline microcephaly at birth, borderline-normal intellectual efficiency, and brain malformations can occur in ASPM-related primary hereditary microcephaly.