A review of the neurological and neurosurgical implications of Down syndrome in children

Neurosurgical Evaluation and Management of Patients with Chromosomal Abnormalities

Patients with chromosomal abnormalities are at risk for numerous neurosurgical pathologies, given the broad impact and multisystem involvement of these disorders. Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), Patau syndrome (trisomy 13), Klinefelter syndrome (47,XXY), and velocardiofacial or DiGeorge syndrome (22q11.2 deletion) are particularly associated with neurosurgical concerns. Given the heterogeneity of concerns and presentations, these patients benefit from multidisciplinary care provided by teams familiar with their specific syndrome.

Moyamoya Disease and Syndrome: A National Inpatient Study of Ischemic Stroke Predictors

OBJECTIVES

Ischemic stroke and hemorrhagic stroke are the most common sequelae of the Moyamoya variants [Moyamoya disease (MMD) and syndrome (MMS)]. We sought to determine the rates of stroke subtypes and the predictive factors of arterial ischemic stroke (AIS) utilizing a large data sample of MMD and MMS patients in the US.

MATERIALS AND METHODS

We queried the 2016 and 2017 National Inpatient Sample database for Moyamoya diagnosis plus any of the following associated conditions; sickle cell disease, neurofibromatosis type 1, cranial radiation therapy or Down Syndrome. Multivariate regression determined the risk factors for AIS onset in MMD and MMS.

RESULTS

2323 patients with a diagnosis of Moyamoya were included; 668 (28.8%) patients were classified as MMS and 1655 (71.2%) as MMD. AIS was the most common presentation in both cohorts; however, MMD patients had higher rates of AIS (20.4 vs 6%, p < 0.001), hemorrhagic stroke (7.4vs 2.5%, p < 0.001), and TIA (3.3vs 0.9%, p = 0.001) compared to MMS patients. Multivariate analysis showed that increasing age [OR = 1.017 95%CI: 1.008-1.03, p < 0.001], lipidemia [OR = 1.32 95%CI: 1.02-1.74, p = 0.049], and current smoking status [OR = 1.43 95%CI: 1.04-1.97, p = 0.026] were independent risk factors for AIS in MMD patients, whereas hypertension [OR = 2.61 95%CI: 1.29-5.25, p = 0.007] and African-American race [OR = 0.274, 95%CI: .117-.64, p = 0.003] were independent predictors in the MMS cohort.

CONCLUSION

AIS is the most common presentation in both, MMD and MMS. However, MMD patients had higher rates of stroke events compared to MMS. Risk factors for AIS in MMD included increasing age, lipidemia and smoking status, whereas in MMS hypertension was the only independent risk factor.

Birth defects in Brazil: Outcomes of a population-based study

Birth defects (BDs) are functional and structural alterations in embryonic or fetal development. With an incidence of approximately 3-5%, BDs are a leading cause of infant mortality and lifelong disability. A population-based prospective case-control study was conducted for one year with 5204 infants, between March 1st, 2011 and February 29th, 2012 in the city of São José do Rio Preto, State of São Paulo, Brazil. The incidence of BDs was 3.2% [95% confidence interval (95%CI): 2.8-3.8%]. The most common congenital anomalies were heart diseases in isolation (11.2%; 95%CI: 7.3-16.9%) followed by Down syndrome (9.5%; 95%CI: 5.9-14.8%), neural tube defects (8.9%; 95%CI: 5.4-14.1), urinary tract anomalies (7.7%; 95%CI: 4.4-12.7%), and polydactyly (7.0%; 95%CI: 4.0-12.0%). The majority of mothers with Down syndrome babies had advanced age. Family members with the same BD, maternal alcohol consumption, gestational diabetes, and previous miscarriages were the most frequent risk factors. The results were similar to published data from other countries except for the incidence of Down syndrome, which was twice as high as reported by other authors and is probably due to the high sociocultural level of the region where the current study was performed, leading to pregnancies at older maternal age.

Case-Control Study of Cephalometrics in Patients with Moyamoya

OBJECTIVE

To determine whether cranial metrics consistently differed between patients with moyamoya and age-, sex-, and race-matched controls.

METHODS

Patients diagnosed with moyamoya disease by cerebral angiogram were obtained from a prospectively collected database through the Department of Neurosurgery at the University of Kansas Medical Center. Control patients matched by decade of age, sex, and race were collected through a deidentified hospital database by International Classification of Diseases-9 and 10 codes for ischemic stroke to identify patients with computed tomography angiograms. Imaging studies for both groups were analyzed to obtain 6 skull metrics: maximum anterior to posterior distance, maximum biparietal distance, bregma to occiput distance, right carotid canal diameter (CCD), left CCD, and cephalic index.

RESULTS

Forty-five patients were identified in each cohort. Measurements of mean anterior to posterior skull diameter, mean biparietal skull diameter, bregma to occiput distances, and calculated cephalic index did not demonstrate a statistically significant difference between patients with moyamoya and control patients. Right carotid canal mean diameter was 4.8 mm for the moyamoya group and 5.4 mm for the control group, with a significant raw mean difference of -0.61 mm (95% confidence interval, -0.95 to -0.27). Left CCD was 4.7 mm for the moyamoya group and 5.5 mm for the control group, resulting in a significant raw mean difference of -0.76 mm (95% confidence interval, -1.09 to -0.43).

CONCLUSIONS

This study identified 2 skull parameters as statistically different in patients with moyamoya compared with a matched control group of patients with ischemic stroke: right CCD and left CCD.

Analysis of Heteroplasmic Variants in the Cardiac Mitochondrial Genome of Individuals with Down Syndrome

Individuals with Down syndrome (DS, trisomy 21) exhibit a pro-oxidative cellular environment as well as mitochondrial dysfunction. Increased oxidative stress may damage the mitochondrial DNA (mtDNA). The coexistence of mtDNA variants in a cell or tissue (i.e., heteroplasmy) may contribute to mitochondrial dysfunction. Given the evidence on mitochondrial dysfunction and the relatively high incidence of multiorganic disorders associated with DS, we hypothesized that cardiac tissue from subjects with DS may exhibit higher frequencies of mtDNA variants in comparison to cardiac tissue from donors without DS. This study documents the analysis of mtDNA variants in heart tissue samples from donors with (n = 12) and without DS (n = 33) using massively parallel sequencing. Contrary to the original hypothesis, the study's findings suggest that the cardiac mitochondrial genomes from individuals with and without DS exhibit many similarities in terms of (1) total number of mtDNA variants per sample, (2) the frequency of mtDNA variants, (3) the type of mtDNA variants, and (4) the patterns of distribution of mtDNA variants. In both groups of samples, the mtDNA control region showed significantly more heteroplasmic variants in comparison to the number of variants in protein- and RNA-coding genes (P < 1.00×10^-4 , ANOVA).

The HSA21 gene EURL/C21ORF91 controls neurogenesis within the cerebral cortex and is implicated in the pathogenesis of Down Syndrome

Copy number variations to chromosome 21 (HSA21) cause intellectual disability and Down Syndrome, but our understanding of the HSA21 genetic factors which contribute to fetal brain development remains incomplete. Here, we focussed on the neurodevelopmental functions for EURL (also known as C21ORF91, Refseq Gene ID:54149), a protein-coding gene at the centromeric boundary of the Down Syndrome Critical Region (DSCR) of HSA21. We report that EURL is expressed during human and mouse cerebral cortex development, and we report that alterations to EURL mRNA levels within the human brain underlie Down Syndrome. Our gene perturbation studies in mice demonstrate that disruptions to Eurl impair progenitor proliferation and neuronal differentiation. Also, we find that disruptions to Eurl impair the long-term positioning and dendritic spine densities of cortical projection neurons. We provide evidence that EURL interacts with the coiled-coil domain-containing protein CCDC85B so as to modulate β-catenin levels in cells. Further, we utilised a fluorescent reporter (8xTOPFLASHd2EGFP) to demonstrate that disruptions to Eurl alter β-catenin signalling in vitro as well as in vivo. Together, these studies highlight EURL as an important new player in neuronal development that is likely to impact on the neuropathogenesis of HSA21-related disorders including Down Syndrome.

Moyamoya syndrome in sickle cell anaemia: a cause of recurrent stroke

Summary We report a case with interesting imaging findings as well as an unfortunate but not unexpected clinical outcome. Our patient, an 8-year-old Jamaican boy of Afro-Caribbean descent with homozygous sickle cell disease, presented with left-sided upper limb weakness. He had a history of recurrent cerebrovascular accidents and transient ischaemic attacks beginning at 4 years of age. MRI revealed old bilateral infarctions and the ivy sign on fluid-attenuated inversion recovery sequences. MR angiography demonstrated numerous collaterals, most apparently arising from the left internal carotid, consistent with moyamoya syndrome. The patient had a full recovery and remained well for almost 2 years when he suffered another stroke.