Loss-of-function mutation in inositol monophosphatase 1 (IMPA1) results in abnormal synchrony in resting-state EEG.

BACKGROUND: Dysregulation of the inositol cycle is implicated in a wide variety of human diseases, including developmental defects and neurological diseases. A homozygous frameshift mutation in IMPA1, coding for the enzyme inositol monophosphatase 1 (IMPase), has recently been associated with severe intellectual disability (ID) in a geographically isolated consanguineous family in Northeastern Brazil (Figueredo et al., 2016). However, the neurophysiologic mechanisms that mediate the IMPA1 mutation and associated ID phenotype have not been characterized. To this end, resting EEG (eyes-open and eyes-closed) was collected from the Figueredo et al. pedigree. Quantitative EEG measures, including mean power, dominant frequency and dominant frequency variability, were investigated for allelic associations using multivariate family-based association test using generalized estimating equations. RESULTS: We found that the IMPA1 mutation was associated with relative decreases in frontal theta band power as well as altered alpha-band variability with no regional specificity during the eyes-open condition. For the eyes-closed condition, there was altered dominant theta frequency variability in the central and parietal regions. CONCLUSIONS: These findings represent the first human in vivo phenotypic assessment of brain function disturbances associated with a loss-of-function IMPA1 mutation, and thus an important first step towards an understanding the pathophysiologic mechanisms of intellectual disability associated with the mutation that affects this critical metabolic pathway.

Sleep findings in Brazilian children with congenital Zika syndrome.

Study Objectives: Zika virus infection during pregnancy may result in congenital Zika syndrome (CZS), whose characteristics are being described. Methods: The present study aimed to investigate the sleep characteristics of 136 infants/toddlers (88 with CZS and 48 with typical development (TD), age and gender matched, 60% girls and 40% boys in both groups) using the Brief Infant Sleep Questionnaire. The ages of children in both groups ranged from 5 to 24 months (CZS 15.9 ± 0.4 vs. TD 15.8 ± 1.0 months, P= 0.90). Results: The results show that 34.1% of CZS and 2% of TD children were defined as poor sleepers, 15% of CZS and 2% of TD children remained awake at night for a period longer than 1 hour, and 24% of CZS and 2% of TD children slept less than 9 hours. The CZS group showed shorter total sleep time (CZS 11.24 ± 2.6 vs. TD 12.02 ± 1.9 hours, P= 0.03) and shorter nocturnal sleep duration than the TD group (CZS 8.2 ± 0.2 vs. TD 9.4 ± 0.2 hours, P= 0.0002). In contrast to the control group (P= 0.02, r= -0.34), in the CZS group, no correlation was found between age and nocturnal wakefulness. Future studies should explore these data in relation to the development and maturation of the central nervous system of these children. Conclusions: Considering the well-known consequences of poor sleep quality on health in several populations, the presence of sleep disorders should be considered in CZS using multidisciplinary treatments.

The phenotypic spectrum of congenital Zika syndrome.

In October 2015, Zika virus (ZIKV) outbreak the Brazilian Ministry of Health (MoH). In response, the Brazilian Society of Medical Genetics established a task force (SBGM-ZETF) to study the phenotype of infants born with microcephaly due to ZIKV congenital infection and delineate the phenotypic spectrum of this newly recognized teratogen. This study was based on the clinical evaluation and neuroimaging of 83 infants born during the period from July, 2015 to March, 2016 and registered by the SBGM-ZETF. All 83 infants had significant findings on neuroimaging consistent with ZIKV congenital infection and 12 had confirmed ZIKV IgM in CSF. A recognizable phenotype of microcephaly, anomalies of the shape of skull and redundancy of the scalp consistent with the Fetal Brain Disruption Sequence (FBDS) was present in 70% of infants, but was most often subtle. In addition, features consistent with fetal immobility, ranging from dimples (30.1%), distal hand/finger contractures (20.5%), and feet malpositions (15.7%), to generalized arthrogryposis (9.6%), were present in these infants. Some cases had milder microcephaly or even a normal head circumference (HC), and other less distinctive findings. The detailed observation of the dysmorphic and neurologic features in these infants provides insight into the mechanisms and timings of the brain disruption and the sequence of developmental anomalies that may occur after prenatal infection by the ZIKV.