Novel Variants of PPP2R1A in Catalytic Subunit Binding Domain and Genotype-Phenotype Analysis in Neurodevelopmentally Delayed Patients.

Neurodevelopmental disorders (NDDs) are a group of high-incidence rare diseases with genetic heterogeneity. PPP2R1A, the regulatory subunit of protein phosphatase 2A, is a recently discovered gene associated with NDDs. Whole/clinical exome sequencing was performed in five patients with a family with NDDs. In vitro experiments were performed to evaluate the mutants' expression and interactions with the complex. The genotype-phenotype correlations of reported cases as well as our patients with PPP2R1A variants were reviewed. We reported five unrelated individuals with PPP2R1A variants, including two novel missense variants and one frameshift variant. The protein expression of the Arg498Leu variant was less than that of the wild-type protein, the frameshift variant Asn282Argfs*14 was not decreased but truncated, and these two variants impaired the interactions with endogenous PPP25RD and PPP2CA. Furthermore, we found that pathogenic variants clustered in HEAT repeats V, VI and VII, and patients with the Met180Val/Thr variants had macrocephaly, severe ID and hypotonia, but no epilepsy, whereas those with Arg258 amino acid changes had microcephaly, while a few had epilepsy or feeding problems. In this study, we reported five NDD patients with PPP2R1A gene variants and expanded PPP2R1A pathogenic variant spectrum. The genotype and phenotype association findings provide reminders regarding the prognostication and evidence for genetic counseling.

Comparison of Genetic Profiles of Neonates in Intensive Care Units Conceived With or Without Assisted Reproductive Technology.

Importance: A growing number of children are conceived with assisted reproductive technology (ART). However, there is a lack of studies systematically analyzing the genetic landscape of live-born children conceived through ART who need intensive care in the neonatal period. Objective: To investigate the incidence and type of molecular defects among neonates conceived through ART who are in intensive care units (NICUs) with suspected genetic conditions. Design, Setting, and Participants: This was a cross-sectional study using data from the China Neonatal Genomes Project, a multicenter national neonatal genome data set managed by the Children's Hospital of Fudan University. All participants were from level III and IV NICUs and included 535 neonates conceived through ART with suspected genetic conditions, with data collected between August 1, 2016, and December 31, 2021, and 1316 naturally conceived neonates with suspected genetic conditions in the same clinical settings, with data collected between August 1, 2016, and December 31, 2018. The data were analyzed between September 2021 and January 2023. Exposures: Whole-exome sequencing or target clinical exome sequencing with pathogenic or likely pathogenic single-nucleotide variant (SNV) and copy number variation (CNV) detection was performed for each individual. Main Outcomes and Measures: The primary outcome was the molecular diagnostic yield, mode of inheritance, spectrum of genetic events, and incidence of de novo variants. Results: A total of 535 neonates conceived through ART (319 boys [59.6%]) and 1316 naturally conceived neonates (772 boys [58.7%]) were included. A genetic diagnosis was established for 54 patients conceived through ART (10.1%), including 34 patients with SNVs (63.0%) and 20 with CNVs (37.0%). In the non-ART group, 174 patients (13.2%) received a genetic diagnosis, including 120 patients with SNVs (69.0%) and 54 with CNVs (31.0%). The overall diagnostic yield was comparable between the ART group and the naturally conceived neonates (10.1% vs 13.2%; odds ratio [OR], 0.74; 95% CI, 0.53-1.02), as was the proportion of SNVs (63.0% vs 69.0%; OR, 0.68; 95% CI, 0.46-1.00) and CNVs (37.0% vs 31.0%; OR, 0.91; 95% CI, 0.54-1.53) detected by sequencing. Furthermore, the proportions of de novo variants in the ART group and the non-ART group were similar (75.9% [41 of 54] vs 64.4% [112 of 174]; OR, 0.89; 95% CI, 0.62-1.30). Conclusions and Relevance: This cross-sectional study of neonates in NICUs suggests that the overall genetic diagnostic yield and the incidence of de novo variants were similar between live-born neonates conceived through ART and naturally conceived neonates in the same settings.

In the developing cerebral cortex: axonogenesis, synapse formation, and synaptic plasticity are regulated by SATB2 target genes.

BACKGROUND: Special AT-rich sequence-binding protein 2 is essential for the development of cerebral cortex and key molecular node for the establishment of proper neural circuitry and function. Mutations in the SATB2 gene lead to SATB2-associated syndrome, which is characterized by abnormal development of skeleton and central nervous systems. METHODS: We generated Satb2 knockout mouse model through CRISPR-Cas9 technology and performed RNA-seq and ChIP-seq of embryonic cerebral cortex. We conducted RT-qPCR, western blot, immunofluorescence staining, luciferase reporter assay and behavioral analysis for experimental verification. RESULTS: We identified 1363 downstream effector genes of Satb2 and correlation analysis of Satb2-targeted genes and neurological disease genes showed that Satb2 contribute to cognitive and mental disorders from the early developmental stage. We found that Satb2 directly regulate the expression of Ntng1, Cdh13, Kitl, genes important for axon guidance, synaptic formation, neuron migration, and Satb2 directly activates the expression of Mef2c. We also showed that Satb2 heterozygous knockout mice showed impaired spatial learning and memory. CONCLUSIONS: Taken together, our study supportsroles of Satb2 in the regulation of axonogenesis and synaptic formation at the early developmental stage and provides new insights into the complicated regulatory mechanism of Satb2 and new evidence to elucidate the pathogen of SATB2-associated syndrome. IMPACT: 1363 downstream effector genes of Satb2 were classified into 5 clusters with different temporal expression patterns. We identified Plxnd1, Ntng1, Efnb2, Ephb1, Plxna2, Epha3, Plxna4, Unc5c, and Flrt2 as axon guidance molecules to regulate axonogenesis. 168 targeted genes of Satb2 were found to regulate synaptic formation in the early development of the cerebral cortex. Transcription factor Mef2c is positively regulated by Satb2, and 28 Mef2c-targeted genes can be directly regulated by Satb2. In the Morris water maze test, Satb2+/- mice showed impaired spatial learning and memory, further strengthening that Satb2 can regulate synaptic functions.