Pilot Study of a Novel Computerized Task to Assess Spatial Learning in Children and Adolescents With Neurofibromatosis Type 1

Abstract Difficulties with visual-spatial learning are frequently observed and often considered to be the hallmark of neurocognitive impairment in neurofibromatosis type 1. The computerized Arena Maze is a virtual environment task that has been developed as a human paradigm to the Morris Water Maze, which is used to evaluate spatial learning in animal models. The authors evaluated this task as a measure of spatial learning in children with neurofibromatosis type 1 compared with their unaffected siblings. Affected children were able to learn the task and navigate the virtual environment; however, they performed more poorly on standard measures of spatial learning and spatial working memory than their siblings. The group with neurofibromatosis type 1 demonstrated decreased proficiency in earlier target trials and had more difficulty in remembering target location. This study demonstrates the potential utility of a novel virtual task to assess spatial learning deficits in children with neurofibromatosis type 1

The genomic landscape of balanced cytogenetic abnormalities associated with human congenital anomalies

Despite the clinical significance of balanced chromosomal abnormalities (BCAs), their characterization has largely been restricted to cytogenetic resolution. We explored the landscape of BCAs at nucleotide resolution in 273 subjects with a spectrum of congenital anomalies. Whole-genome sequencing revised 93% of karyotypes and demonstrated complexity that was cryptic to karyotyping in 21% of BCAs, highlighting the limitations of conventional cytogenetic approaches. At least 33.9% of BCAs resulted in gene disruption that likely contributed to the developmental phenotype, 5.2% were associated with pathogenic genomic imbalances, and 7.3% disrupted topologically associated domains (TADs) encompassing known syndromic loci. Remarkably, BCA breakpoints in eight subjects altered a single TAD encompassing MEF2C, a known driver of 5q14.3 microdeletion syndrome, resulting in decreased MEF2C expression. We propose that sequence-level resolution dramatically improves prediction of clinical outcomes for balanced rearrangements and provides insight into new pathogenic mechanisms, such as altered regulation due to changes in chromosome topology

Prevalence of sleep problems in Smith-Lemli-Opitz syndrome.

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive genetic disorder, characterized by multiple congenital anomalies, and intellectual disability. It is caused by a genetically inherited deficiency of the enzyme 7-dehydrocholesterol-delta-7-reductase, which results in increased serum levels of 7-dehydrocholesterol (7-DHC), and decreased levels of cholesterol. This study assesses the prevalence of sleep problems in patients with SLOS. The study group comprised 18 subjects with SLOS, ages 2-31 years (median 10.7 ± 8.5 years). Parents completed several questionnaires (Intake Demographic Form; Pediatric Sleep Questionnaire; Pediatric Daytime Sleepiness Scale). The SLOS subjects had symptoms of sleep-disordered breathing (50% snoring; 66.7% mouth breathing), problems with sleep onset [difficulty falling asleep (61.1%) sleep onset time \u3e30 min (62%)], sleep maintenance [wake up screaming (61.1%), waking up more than twice (44.4%), having trouble falling back to sleep (66.7%), waking up early in the morning (61.1%), and restless sleep (50%)]. The subjects with SLOS needed parents in the room to fall asleep (50%), watch TV or listen to music to fall asleep (44.4%), and described bed sharing (33.3%), indicating sleep-anxiety and sleep-associations. Symptoms of excessive-daytime-sleepiness were frequently reported [un-refreshed in the morning (38.9%), daytime sleepiness (44.4%), and daytime naps (55.6%)]. Parents frequently observed difficulty of organizing tasks (66.7%), and easy distractibility (88.9%). Sleep problems such as sleep-disordered breathing, sleep-related anxiety and sleep associations, disturbed sleep patterns at night, and excessive daytime sleepiness are frequent in children with SLOS

Smith-Lemli-Opitz syndrome in trisomy 13: how does the mix work?

BackgroundTrisomy 13 and Smith-Lemli-Opitz syndrome (SLOS) are both well-recognized multiple congenital anomaly/mental retardation syndromes.CaseIn this report we describe a male newborn with trisomy 13 who also has features of SLOS, such as 2/3 toe syndactyly and a shawl-like scrotum. Biochemical analysis was consistent with SLOS, and limited molecular analysis revealed 1 mutation in the DHCR7 gene.ConclusionsThe challenges in establishing the diagnosis of SLOS in this patient are presented and the unique coexistence of the 2 major malformation syndromes is discussed. Given the overlapping phenotype of the 2 syndromes, our report should encourage further research on cholesterol biosynthesis in patients with trisomy 13

Diagnostic utility of array-based comparative genomic hybridization in a clinical setting.

Array-based comparative genomic hybridization is a recently introduced technique for the detection of submicroscopic genomic imbalances (deletions or duplications) across the entire genome. To assess the potential utility of a widely available array-based comparative genomic hybridization platform that targets specific, clinically relevant, loci across the genome for cytogenetic diagnosis in a clinical setting, we reviewed the medical records of all 373 patients at Children's Hospital Boston who had normal chromosomal analysis and were tested with this targeted array-based comparative genomic hybridization over a 1-year period from November 1, 2004 to October 31, 2005. These patients were tested because of a suspicion of chromosomal abnormalities based on their clinical presentation. Thirty-six patients (9.7%) had abnormal array-based comparative genomic hybridization results. Twenty patients (5.4%) had potentially pathogenetic genomic imbalances and 16 patients (4.3%) had copy number variations that are not believed to be pathogenetic. Thirteen of 234 patients (5.6%) with mental retardation/global developmental delay, 10/114 patients (8.8%) with facial dysmorphism, 5/58 patients (8.6%) with multiple congenital anomalies, and 4/35 patients (11.4%) with both facial dysmorphism and multiple congenital anomalies had potentially pathogenetic genomic imbalances. Targeted array-based comparative genomic hybridization is a clinically available test that is useful in the evaluation of patients suspected of having chromosomal disorders. However, it is best used as an adjunct to chromosomal analysis when a clear genetic diagnosis is unavailable

Fryns syndrome with Hirschsprung disease: support for possible neural crest involvement.

Fryns syndrome is an autosomal recessive multiple congenital anomaly/mental retardation syndrome characterized by coarse face, distal limb hypoplasia, and diaphragmatic anomalies. We describe a newborn girl with Fryns syndrome and Hirschsprung disease, an association that has been reported in five previous cases. These patients support the hypothesis that the neural crest plays a role in the pathogenesis of Fryns syndrome. Clinically asymptomatic or subtle anomalies that are in the spectrum of neural crest maldevelopment should be sought in all patients with Fryns syndrome including stillbirths, neonatal deaths, as well as long-term survivors. We suspect that the clinical observation about Hirschsprung disease and Fryns syndrome may provide insight into its molecular mechanisms and candidate genes

Clinical presentation of 13 patients with subtelomeric rearrangements and a review of the literature.

To re-examine the potential clinical indications for subtelomeric FISH testing and to provide additional cases to the growing literature on subtelomeric abnormalities and their genotype-phenotype correlations, we present a single center case series of 13 patients with chromosomal abnormalities detected by subtelomeric FISH testing over a 21 month period. The most common abnormality involved chromosome 1p (23%). Partial monosomy was present in 69% of the patients, complex rearrangements in 23%, and partial trisomy in 8%. The mean time from first normal karyotype to positive subtelomeric FISH result was 3.8 years (n = 11, median 3.5 years, range: 6 months-10 years). One patient had an abnormal high resolution karyotype recognized retrospectively, and two other patients had abnormal karyotypes that were fully deciphered only after subtelomeric FISH analysis. Eighty five percent of cases occurred de novo. The subtelomeric FISH results were useful for adjusting the recurrence risks and helping to focus medical screening and monitoring. The results impacted family planning and satisfied families in search of a diagnosis. Our findings support the use of subtelomeric FISH analysis as a second tier test in patients suspected of having a chromosomal abnormality with a normal karyotype. Potential benefits of subtelomeric FISH testing include faster time to diagnosis, better informed patient prognosis, and more accurate genetic counseling