Heterozygous HMGB1 loss-of-function variants are associated with developmental delay and microcephaly

Extracellular Adipose Matrix Hydrogel Laden with Adipose-Derived Stem Cell Modulates Macrophage Polarization for Enhanced Full-Thickness Skin Wound Repair

Adipose-derived stem cells (ADSC) represent a promising approach for wound healing, while the limited survival rate has restricted their application. To address this, we equipped a hydrogel from acellular porcine adipose tissue (HAPA) with ADSC to fabricate the HAPA + ADSC composite hydrogel. In addition to serving as a carrier for stem cell delivery, the bioactive components of the HAPA hydrogel support immune regulation and tissue repair. In this study, we demonstrated that the HAPA + ADSC composite could effectively modulate macrophage polarization, promote angiogenesis, and regulate extracellular matrix (ECM) deposition and remodeling, thereby substantially accelerating wound healing. Additionally, transcriptomic sequencing analysis indicated that the HAPA + ADSC composite upregulated Nfkbia and Nfkbie to inhibit the nuclear transcription of RelA-p50 heterodimer so that macrophages polarization toward an M1 phenotype is suppressed. The combined effects of ADSC and HAPA hydrogel make it a promising candidate for functional skin wound healing.

Prenatal phenotype of PNKP-related microcephaly, seizures, and developmental delay: A case report and literature review

RATIONALE

Microcephaly, epilepsy, and developmental delay (MCSZ) is a rare neurodevelopmental disorder associated with autosomal recessive inheritance of mutations in the polynucleotide kinase 3'-phosphatase (PNKP) gene. Prompt identification and management are essential, as delayed diagnosis or intervention may result in severe complications or mortality. In this case, prenatal screening in the second trimester detected fetal microcephaly with a gradual decline in head circumference, prompting the decision to terminate the pregnancy. Subsequent genetic analysis of the fetal tissue confirmed the presence of compound heterozygous mutations in the PNKP gene.

PATIENT CONCERNS

The patient, a 34-year-old remarried female with no history of consanguineous marriage, underwent 2 mid-trimester termination procedures due to fetal microcephaly and sought counseling for reproductive assistance.

DIAGNOSES

The patient's carrier status for PNKP mutations was ascertained through whole-exome sequencing of the termination tissue and molecular genetic testing for monogenic disorders. The terminated fetus was diagnosed with MCSZ, a condition associated with compound heterozygous mutations in the PNKP gene.

INTERVENTIONS

Fetal microcephaly was identified via mid-trimester prenatal ultrasound, leading to the termination of the pregnancy during the same trimester. Subsequent genetic analysis of the immediate family revealed compound heterozygous mutations in the PNKP gene as the underlying cause of MCSZ. Genetic counseling was provided, followed by 1 cycle of preimplantation genetic testing for monogenic.

OUTCOMES

The patient carried the heterozygous c.1188 + 1G > A PNKP mutation, whereas her husband carried the heterozygous c.976G > A PNKP mutation. The fetus was found to have compound heterozygous mutations c.976G > A and c.1188 + 1G > A. After counseling, the couple underwent 1 cycle of preimplantation genetic testing for monogenic, unfortunately, no pregnancy occurred after the 2 embryos were transferred.

LESSONS

MCSZ, a condition caused by PNKP mutations, is exceedingly rare. Women with a history of adverse pregnancy outcomes should undergo close monitoring during prenatal checkups. If fetal microcephaly is detected, it is essential to strictly follow obstetric guidelines for prenatal care, such as comprehensive cranial magnetic resonance imaging and genetic testing for confirmation. Avoidance of consanguineous marriages is advised. Early detection and timely intervention are key to preventing adverse pregnancy outcomes.

A Case Report on 13q12.3 Microdeletion Syndrome Caused by HMGB1 Haploinsufficiency

Heterozygous microdeletions at 13q12.3 are associated with a rare genetic disorder, 13q12.3 microdeletion syndrome, characterized by intellectual disability, microcephaly, development delay, facial dysmorphisms, atopy, and obesity. Reported 13q12.3 microdeletions vary in size and typically encompass multiple genes. Previous studies have defined a minimal overlap region of 13q12.3 microdeletions and suggested that most of the phenotype associated with the 13q12.3 microdeletion syndrome could be attributed to the loss of the high mobility group box 1 (HMGB1) gene within the overlap region. Here, we report a pediatric patient who had typical phenotypic features of 13q12.3 microdeletion syndrome, including motor and moderate speech developmental delays, microcephaly, and severe atopy, along with anxiety and aggressive behaviors. Trio-based microarray analysis identified a 62-kb apparently de novo heterozygous deletion at 13q12.3 in the proband, fully encompassing all coding exons of the HMGB1 gene yet not affecting any other neighboring genes. This case report presents a rare HMGB1 single-gene deletion in a patient with classic features of 13q12.3 microdeletion syndrome, allowing a better delineation of clinical phenotypes associated with the loss of HMGB1. Our findings, together with previous reports, strongly support the pathogenic role of HMGB1 haploinsufficiency in the 13q12.3 microdeletion syndrome.

A Panel-Agnostic Strategy 'HiPPo' Improves Diagnostic Efficiency in the UK Genomic Medicine Service

Genome sequencing is available as a clinical test in the UK through the Genomic Medicine Service (GMS). The GMS analytical strategy predominantly filters genome data on preselected gene panels. Whilst this reduces variants requiring assessment by reporting laboratories, pathogenic variants outside applied panels may be missed, and variants in genes without established disease-gene relationships are largely ignored. This study compares the analysis of a research exome to a GMS clinical genome for the same patients. For the research exome, we applied a panel-agnostic approach filtering for variants with High Pathogenic Potential (HiPPo) using ClinVar, allele frequency, and in silico prediction tools. We then restricted HiPPo variants to Gene Curation Coalition (GenCC) disease genes. These results were compared with the GMS genome panel-based approach. Twenty-four participants from eight families underwent parallel research exome and GMS genome sequencing. Exome HiPPo analysis identified a similar number of variants as the GMS panel-based approach. GMS genome analysis returned two pathogenic variants and one de novo variant. Exome HiPPo analysis returned the same variants plus an additional pathogenic variant and three further de novo variants in novel genes, where case series are underway. When HiPPo was restricted to GenCC disease genes, statistically fewer variants required assessment to identify more pathogenic variants than reported by the GMS, giving a diagnostic rate per variant assessed of 20% for HiPPo versus 3% for the GMS. With UK plans to sequence 5 million genomes, strategies are needed to optimise genome analysis beyond gene panels whilst minimising the burden of variants requiring clinical assessment.

The multifunctional protein HMGB1: 50 years of discovery

Fifty years since the initial discovery of HMGB1 in 1973 as a structural protein of chromatin, HMGB1 is now known to regulate diverse biological processes depending on its subcellular or extracellular localization. These functions include promoting DNA damage repair in the nucleus, sensing nucleic acids and inducing innate immune responses and autophagy in the cytosol and binding protein partners in the extracellular environment and stimulating immunoreceptors. In addition, HMGB1 is a broad sensor of cellular stress that balances cell death and survival responses essential for cellular homeostasis and tissue maintenance. HMGB1 is also an important mediator secreted by immune cells that is involved in a range of pathological conditions, including infectious diseases, ischaemia-reperfusion injury, autoimmunity, cardiovascular and neurodegenerative diseases, metabolic disorders and cancer. In this Review, we discuss the signalling mechanisms, cellular functions and clinical relevance of HMGB1 and describe strategies to modify its release and biological activities in the setting of various diseases.

A panel-agnostic strategy 'HiPPo' improves diagnostic efficiency in the UK Genome Medicine Service

Genome sequencing is now available as a clinical test on the National Health Service (NHS) through the Genome Medicine Service (GMS). The GMS have set out an analytical strategy that predominantly filters genome data on a pre-selected gene panel(s). Whilst this approach reduces the number of variants requiring assessment by reporting laboratories, pathogenic variants outside of the gene panel applied may be missed, and candidate variants in novel genes are largely ignored. This study sought to compare a research exome analysis to an independent clinical genome analysis performed through the NHS for the same group of patients. When analysing the exome data, we applied a panel agnostic approach filtering for variants with High Pathogenic Potential (HiPPo) using ClinVar, allele frequency, and in silico prediction tools. We then compared this gene agnostic analysis to the panel-based approach as applied by the GMS to genome data. Later we restricted HiPPo variants to a panel of the Gene Curation Coalition (GenCC) morbid genes and compared the diagnostic yield with the variants filtered using the GMS strategy. 24 patients from 8 families underwent parallel research exome sequencing and GMS genome sequencing. HiPPo analysis applied to research exome data identified a similar number of variants as the gene panel-based approach applied by the GMS. GMS clinical genome analysis identified and returned 2 pathogenic variants and 3 variants of uncertain significance. HiPPo research exome analysis identified the same variants plus an additional pathogenic variant and a further 3 de novo variants of uncertain significance in novel genes, where case series and functional studies are underway. When HiPPo was restricted to GenCC disease genes (strong or definitive), the same pathogenic variants were identified yet statistically fewer variants required assessment to identify more diagnostic variants than reported by the GMS genome strategy. This gave a diagnostic rate per variant assessed of 20% for HiPPo restricted to GenCC versus 3% for the GMS panel-based approach. With plans to sequence 5 million more NHS patients, strategies are needed to optimise the full potential of genome data beyond gene panels whilst minimising the burden of variants that require clinical assessment.