MECP2, a gene associated with Rett syndrome in humans, shows conserved coding regions, independent Alu insertions, and a novel transcript across primate evolution

Regulation, diversity and function of MECP2 exon and 3'UTR isoforms

The methyl-CpG-binding protein 2 (MECP2) is a critical global regulator of gene expression. Mutations in MECP2 cause neurodevelopmental disorders including Rett syndrome (RTT). MECP2 exon 2 is spliced into two alternative messenger ribonucleic acid (mRNA) isoforms encoding MECP2-E1 or MECP2-E2 protein isoforms that differ in their N-termini. MECP2-E2, isolated first, was used to define the general roles of MECP2 in methyl-deoxyribonucleic acid (DNA) binding, targeting of transcriptional regulatory complexes, and its disease-causing impact in RTT. It was later found that MECP2-E1 is the most abundant isoform in the brain and its exon 1 is also mutated in RTT. MECP2 transcripts undergo alternative polyadenylation generating mRNAs with four possible 3'untranslated region (UTR) lengths ranging from 130 to 8600 nt. Together, the exon and 3'UTR isoforms display remarkable abundance disparity across cell types and tissues during development. These findings indicate discrete means of regulation and suggest that protein isoforms perform non-overlapping roles. Multiple regulatory programs have been explored to explain these disparities. DNA methylation patterns of the MECP2 promoter and first intron impact MECP2-E1 and E2 isoform levels. Networks of microRNAs and RNA-binding proteins also post-transcriptionally regulate the stability and translation efficiency of MECP2 3'UTR isoforms. Finally, distinctions in biophysical properties in the N-termini between MECP2-E1 and E2 lead to variable protein stabilities and DNA binding dynamics. This review describes the steps taken from the discovery of MECP2, the description of its key functions, and its association with RTT, to the emergence of evidence revealing how MECP2 isoforms are differentially regulated at the transcriptional, post-transcriptional and post-translational levels.

Clinical presentation of Rett syndrome in relation to quality of life and family functioning

Objective

Rett syndrome (RTT) is a chronic condition that manifest in young children, with concomitant comorbidities such as respiratory problems, scoliosis, epilepsy, and malnutrition, which may affect children’s quality of life (QoL) and family functioning. The objective of this cross-sectional descriptive correlation study was to understand the clinical presentation of RTT in relation to QoL and family functioning.

Methods

We included 23 parents of children with RTT. In this study, we used the PedsQL™ Family Impact Module, the Pediatric Quality of Life Inventory 4.0 generic core scales (PedsQL™ 4.0), and an author-designed questionnaire to assess QoL and family functioning.

Results

A significant relationship was observed between PedsQL™ 4.0 score and child’s age in the physical functioning dimension. Children aged 8 to 12 years demonstrated significantly higher scores than those in the other age groups. Malnutrition in the child significantly affected functioning of the family in the family relationships dimension. Children receiving 5 hours of rehabilitation treatment a week had significantly higher QoL in the school functioning dimension.

Conclusions

QOL in children with RTT, as perceived by their parents, is reduced. RTT has a significant negative correlation with family functioning.

A phylogenomic perspective on the robust capuchin monkey (Sapajus) radiation: First evidence for extensive population admixture across South America

Phylogenetic relationships amongst the robust capuchin monkeys (genus Sapajus) are poorly understood. Morphology-based taxonomies have recognized anywhere from one to twelve different species. The current IUCN (2017) classification lists eight robust capuchins: S. xanthosternos, S. nigritus, S. robustus, S. flavius, S. libidinosus, S. cay, S. apella and S. macrocephalus. Here, we assembled the first phylogenomic data set for Sapajus using ultra-conserved elements (UCEs) to reconstruct a capuchin phylogeny. All phylogenomic analyses strongly supported a deep divergence of Sapajus and Cebus clades within the capuchin monkeys, and provided support for Sapajus nigritus, S. robustus and S. xanthosternos as distinct species. However, the UCE phylogeny lumped the putative species S. cay, S. libidinosus, S. apella, S. macrocephalus, and S. flavius together as a single widespread lineage. A SNP phylogeny constructed from the UCE data was better resolved and recovered S. flavius and S. libidinosus as sister species; however, S. apella, S. macrocephalus, and S. cay individuals were recovered in two geographic clades, from northeastern and southwestern Amazon, rather than clustering by currently defined morphospecies. STRUCTURE analysis of population clustering revealed widespread admixture among Sapajus populations within the Amazon and even into the Cerrado and Atlantic Forest. Difficulty in assigning species by morphology may be a result of widespread population admixture facilitated through frequent movement across major rivers and even ecosystems by robust capuchin monkeys.

The Quality of Life in Girls with Rett Syndrome

Nowadays, quality of life is receiving an increasing attention in all scientific areas. Rett syndrome (RTT) is a rare neurological development, affecting mainly females. The congenital disease affects the central nervous system, and is one of the most common causes of severe intellectual disability. The aim of our study is to evaluate the effect of RTT on the quality of life of people who are affected. Both parents of 18 subjects, all female, diagnosed with RTT, took part in the research. Quality of life was assessed using the Italian version of the Impact of Childhood Illness Scale. This scale consists of 30 questions that investigate the effect of illness on children, parents and families. For each question, the parent was asked to rate two variables: frequency and importance. Another questionnaire was administered to obtain medical history, diagnostic and therapeutic data of the persons with RTT. Our data show that RTT has a considerable impact on both the child’s development and the entire family. Parents’ answers demonstrated that their child’s illness had consequences for the child and how the family coped with it. For this reason, attention should be directed at psychological and social aspects, as well as attitudes, manners, reactions and effects such disturbances can have on the entire family.