Hoyeraal-Hreidarsson syndrome with a DKC1 mutation identified by whole-exome sequencing

Research progress of RNA pseudouridine modification in nervous system

Recent advances of pseudouridine (Ψ, 5-ribosyluracil) modification highlight its crucial role as a post-transcriptional regulator in gene expression and its impact on various RNA processes. Ψ synthase (PUS), a category of RNA-modifying enzymes, orchestrates the pseudouridylation reaction. It can specifically recognize conserved sequences or structural motifs within substrates, thereby regulating the biological function of various RNA molecules accurately. Our comprehensive review underscored the close association of PUS1, PUS3, PUS7, PUS10, and dyskerin PUS1 with various nervous system disorders, including neurodevelopmental disorders, nervous system tumors, mitochondrial myopathy, lactic acidosis and sideroblastic anaemia (MLASA) syndrome, peripheral nervous system disorders, and type II myotonic dystrophy. In light of these findings, this study elucidated how Ψ strengthened RNA structures and contributed to RNA function, thereby providing valuable insights into the intricate molecular mechanisms underlying nervous system diseases. However, the detailed effects and mechanisms of PUS on neuron remain elusive. This lack of mechanistic understanding poses a substantial obstacle to the development of therapeutic approaches for various neurological disorders based on Ψ modification.

The importance of pseudouridylation: human disorders related to the fifth nucleoside

Pseudouridylation is one of the most abundant RNA modifications in eukaryotes, making pseudouridine known as the "fifth nucleoside." This highly conserved alteration affects all non-coding and coding RNA types. Its role and importance have been increasingly widely researched, especially considering that its absence or damage leads to serious hereditary diseases. Here, we summarize the human genetic disorders described to date that are related to the participants of the pseudouridylation process.

Ocular findings and genomics of X-linked recessive disorders: A review

Advent of new sequencing technologies and modern diagnostic procedures has opened the door for a deeper understanding of disorders about which little was known previously. Discovery of novel genes, new genetic variants in previously known genes and better techniques of functional validation has immensely contributed to unraveling the molecular basis of genetic disorders. Availability of knockout animal models like the zebrafish and gene editing tools like CRISPR-Cas9 has elucidated the function of many new genes and helped us to better understand the functional consequences of various gene defects. This has also led to better diagnosis and therapeutic interventions. In this context, a good body of research work has been done on X-linked recessive disorders with ocular findings. This review will focus on ocular and genetic findings of these rare disorders. To our knowledge, this is the first comprehensive review encompassing ocular and genomic spectrum of X-linked recessive disorders.

Diagnostics of rare disorders: whole-exome sequencing deciphering locus heterogeneity in telomere biology disorders

Background

The telomere biology disorders (TBDs) include a range of multisystem diseases characterized by mucocutaneous symptoms and bone marrow failure. In dyskeratosis congenita (DKC), the clinical features of TBDs stem from the depletion of crucial stem cell populations in highly proliferative tissues, resulting from abnormal telomerase function. Due to the wide spectrum of clinical presentations and lack of a conclusive laboratory test it may be challenging to reach a clinical diagnosis, especially if patients lack the pathognomonic clinical features of TBDs.

Methods

Clinical sequencing was performed on a cohort of patients presenting with variable immune phenotypes lacking molecular diagnoses. Hypothesis-free whole-exome sequencing (WES) was selected in the absence of compelling diagnostic hints in patients with variable immunological and haematological conditions.

Results

In four patients belonging to three families, we have detected five novel variants in known TBD-causing genes (DKC1, TERT and RTEL1). In addition to the molecular findings, they all presented shortened blood cell telomeres. These findings are consistent with the displayed TBD phenotypes, addressing towards the molecular diagnosis and subsequent clinical follow-up of the patients.

Conclusions

Our results strongly support the utility of WES-based approaches for routine genetic diagnostics of TBD patients with heterogeneous or atypical clinical presentation who otherwise might remain undiagnosed.

Electronic supplementary material

The online version of this article (10.1186/s13023-018-0864-9) contains supplementary material, which is available to authorized users.

Novel HSPG2 mutations causing Schwartz‑Jampel syndrome type 1 in a Chinese family: A case report

Schwartz-Jampel syndrome type 1 (SJS1) is a rare autosomal recessive disease caused by mutations in the gene heparan sulfate proteoglycan 2 (HSPG2; also known as basement membrane‑specific heparin sulfate). In the present study, a 10‑year‑old female SJS1 proband from a Chinese family, who was diagnosed by X‑ray and physical examination, was recruited. The key clinical features of the patient with SJS1 included short stature, joint contractures, pigeon breast, and myotonia that led to progressive stiffness of the face and limbs; barely discernible kyphosis was also noted. Genetic testing using whole exome sequencing and Sanger sequencing was performed for the proband and family members. A total of 2 novel mutations (c.8788G>A; p.Glu2930Lys and c.11671+5G>A) in the HSPG2 gene were identified in the proband. The family members harboring 1 heterozygous mutation in HSPG2 did not exhibit any skeletal abnormalities. The results of the present study suggested that the compound heterozygous mutations in HSPG2 may be responsible the induction of SJS1, and demonstrated the genotype‑phenotype associations between mutations in the HSPG2 gene and clinical characteristics of SJS1.

Clinical Application of Genome and Exome Sequencing as a Diagnostic Tool for Pediatric Patients: a Scoping Review of the Literature

PURPOSE

Availability of clinical genomic sequencing (CGS) has generated questions about the value of genome and exome sequencing as a diagnostic tool. Analysis of reported CGS application can inform uptake and direct further research. This scoping literature review aims to synthesize evidence on the clinical and economic impact of CGS.

METHODS

PubMed, Embase, and Cochrane were searched for peer-reviewed articles published between 2009 and 2017 on diagnostic CGS for infant and pediatric patients. Articles were classified according to sample size and whether economic evaluation was a primary research objective. Data on patient characteristics, clinical setting, and outcomes were extracted and narratively synthesized.

RESULTS

Of 171 included articles, 131 were case reports, 40 were aggregate analyses, and 4 had a primary economic evaluation aim. Diagnostic yield was the only consistently reported outcome. Median diagnostic yield in aggregate analyses was 33.2% but varied by broad clinical categories and test type.

CONCLUSION

Reported CGS use has rapidly increased and spans diverse clinical settings and patient phenotypes. Economic evaluations support the cost-saving potential of diagnostic CGS. Multidisciplinary implementation research, including more robust outcome measurement and economic evaluation, is needed to demonstrate clinical utility and cost-effectiveness of CGS.

Physiological and Pathological Function of Serine/Arginine-Rich Splicing Factor 4 and Related Diseases

Serine/arginine-rich splicing factors (SRSFs) have one or two RNA recognition motifs in the N terminal and a serine/arginine-enriched domain in the C terminal. SRSFs are essential components of spliceosomes and are involved in alternative splicing, spliceosome assembly, mRNA export, and nonsense-mediated mRNA decay. The maintenance of cellular and tissue homeostasis relies on accurate alternative splicing, and various patterns of abnormal alternative splicing can cause different diseases. SRSF4 is associated with many physiological and pathological processes and has applications in the diagnosis and prognosis of specific diseases. In this review, we discuss knowledge of SRSF4 in physiological and pathological processes and highlight the applications of SRSF4 in the regulation of gene expression and associated diseases.

Novel WISP3 mutations causing progressive pseudorheumatoid dysplasia in two Chinese families

Progressive pseudorheumatoid dysplasia (PPD) is a rare disease caused by mutations in the gene for Wnt1-inducible signaling pathway protein 3 (WISP3). Here, we report the clinical and radiographic manifestations of two Chinese PPD patients. We performed whole-exome sequencing for one patient and sequenced the WISP3 for the other. Three WISP3 mutations (c.396T>G, c.721T>G and c.679dup) were identified; the two missense mutations were novel. Our study expanded the WISP3 mutation spectrum.