Rhombencephalosynapsis is a rare congenital abnormality characterised by dorsal fusion of the cerebellar hemispheres, agenesis or hypogenesis of the vermis, fusion of dentate nuclei and superior cerebellar peduncles. We describe 9 children, aged 1.5 to 6 years, with rhombencephalosynapsis. Isolated rhombencephalosynapsis was found in 2 patients, hydrocephalus in 3 children and another 3 children had ventriculomegaly. Additional supratentorial abnormalities were documented in 5 patients. Clinical findings ranged from mild truncal ataxia and normal cognitive abilities to severe cerebral palsy and mental retardation. No correlation between clinical findings and magnetic resonance imaging could be established so far.

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Background : Segmental vitiligo is characterized by a unilateral and localized distribution. So far, the underlying mechanism is still an enigma. Objectives To get an insight into the aetiopathogenesis of segmental vitiligo by comparison with the distribution pattern of dermatoses with a possible mosaic or neurogenic background. Methods : In this retrospective observational study the distribution pattern of 724 unilateral, linear or band-shaped control lesions was compared with 181 segmental vitiligo lesions. Clinical photographs were used to score similarities according to a defined grading system (scale ranging from 0 for no similarities to 4 for complete similarity). Control lesions were evaluated both individually and after grouping into different cell types. Results : In general, only a minority of cases (36.9%), showed similarities (grade 1-4) between control lesions and segmental vitiligo. Grade 2-4 similarities were seen mainly in segmental lentiginosis (73.7%, P < 0 001). The best grade for correspondence (grade 3-4) was observed significantly more only in segmental lentiginosis (36.8% vs. 3.5%, P < 0 001) and epidermal naevus verrucosus (12.5% vs. 3.7%, P = 0 008) compared with the other control lesions. The distribution pattern of segmental vitiligo significantly overlapped those of other disorders originating from melanocytes. Conclusions : Our results demonstrate that the distribution pattern of segmental vitiligo is not entirely similar to any other skin disease, although some mosaic skin disorders have more overlap with segmental vitiligo than others. The remarkable clinical similarity with several cases of mosaic diseases involving melanocytes supports the hypothesis that cutaneous mosaicism may be involved in segmental vitiligo

Macrocerebellum is a rare finding characterized by an abnormally large cerebellum. Only few patients with a syndromal or isolated macrocerebellum have been reported so far. This article aims to categorize the magnetic resonance imaging (MRI) findings, quantitate the macrocerebellum by volumetric analysis, characterize the neurological and dysmorphic features and cognitive outcome, and report the results of genetic analyses in children with macrocerebellum. All MR images were qualitatively evaluated for infratentorial and supratentorial abnormalities. Volumetric analysis was performed. Data about neurological and dysmorphic features, outcome, and genetic analysis were collected from clinical histories and follow-up examinations. Five patients were included. Volumetric analysis in three patients confirmed large cerebellar size compared to age-matched controls. MR evaluation showed that thickening of the cortical gray matter of the cerebellar hemispheres is responsible for the macrocerebellum. Additional infratentorial and supratentorial abnormalities were present in all patients. Muscular hypotonia, as well as impaired motor and cognitive development, was found in all patients, with ocular movement disorders in three of five patients. The five patients differed significantly in terms of dysmorphic features and involvement of extracerebral organs. Submicroscopic chromosomal aberrations were found in two patients. Macrocerebellum is caused by thickening of the cortical gray matter of the cerebellar hemispheres, suggesting that cerebellar granule cells may be involved in its development. Patients with macrocerebellum show highly heterogeneous neuroimaging, clinical, and genetic findings, suggesting that macrocerebellum is not a nosological entity, but instead represents the structural manifestation of a deeper, more basic biological disturbance common to heterogeneous disorders.

BackgroundThe nosological assignment of congenital ocular motor apraxia type Cogan (COMA) is still controversial. While regarded as a distinct entity by some authorities including the Online Mendelian Inheritance in Man catalog of genetic disorders, others consider COMA merely a clinical symptom.MethodsWe performed a retrospective multicenter data collection study with re-evaluation of clinical and neuroimaging data of 21 previously unreported patients (8 female, 13 male, ages ranging from 2 to 24 years) diagnosed as having COMA.ResultsOcular motor apraxia (OMA) was recognized during the first year of life and confined to horizontal pursuit in all patients. OMA attenuated over the years in most cases, regressed completely in two siblings, and persisted unimproved in one individual. Accompanying clinical features included early onset ataxia in most patients and cognitive impairment with learning disability (n = 6) or intellectual disability (n = 4). Re-evaluation of MRI data sets revealed a hitherto unrecognized molar tooth sign diagnostic for Joubert syndrome in 11 patients, neuroimaging features of Poretti-Boltshauser syndrome in one case and cerebral malformation suspicious of a tubulinopathy in another subject. In the remainder, MRI showed vermian hypo-/dysplasia in 4 and no abnormalities in another 4 patients. There was a strong trend to more severe cognitive impairment in patients with Joubert syndrome compared to those with inconclusive MRI, but otherwise no significant difference in clinical phenotypes between these two groups.ConclusionsSystematical renewed analysis of neuroimaging data resulted in a diagnostic reappraisal in the majority of patients with early-onset OMA in the cohort reported here. This finding poses a further challenge to the notion of COMA constituting a separate entity and underlines the need for an expert assessment of neuroimaging in children with COMA, especially if they show cognitive impairment.Electronic supplementary materialThe online version of this article (doi:10.1186/s13023-016-0486-z) contains supplementary material, which is available to authorized users.

Purpose This study aimed to delineate the genetic basis of congenital ocular motor apraxia (COMA) in patients not otherwise classifiable. Methods We compiled clinical and neuroimaging data of individuals from six unrelated families with distinct clinical features of COMA who do not share common diagnostic characteristics of Joubert syndrome or other known genetic conditions associated with COMA. We used exome sequencing to identify pathogenic variants and functional studies in patient-derived fibroblasts. Results In 15 individuals, we detected familial as well as de novo heterozygous truncating causative variants in the Suppressor of Fused (SUFU) gene, a negative regulator of the Hedgehog (HH) signaling pathway. Functional studies showed no differences in cilia occurrence, morphology, or localization of ciliary proteins, such as smoothened. However, analysis of expression of HH signaling target genes detected a significant increase in the general signaling activity in COMA patient–derived fibroblasts compared with control cells. We observed higher basal HH signaling activity resulting in increased basal expression levels of GLI1, GLI2, GLI3, and Patched1. Neuroimaging revealed subtle cerebellar changes, but no full-blown molar tooth sign. Conclusion Taken together, our data imply that the clinical phenotype associated with heterozygous truncating germline variants in SUFU is a forme fruste of Joubert syndrome.

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population-based differences in genotype and phenotype heterogeneity are important for targeted and patient-specific diagnosis and treatment, counseling, and screening strategies.OBJECTIVE To report disease-causing variants and their detailed phenotype in patients with bilateral congenital cataract from a single center in Switzerland and thereby draw a genetic map and perform a genotype-phenotype comparison of this cohort.DESIGN, SETTING, AND PARTICIPANTS This clinical and molecular-genetic cohort study took place through the collaboration of the