01. Understanding Hotspot Pathogenic Mutations
02. Familial Dysautonomia: ELP1 Intronic Point Mutation
03. Facioscapulohumeral Muscular Dystrophy: Abnormal DUX4 Expression
Welcome to the ‘Ten Deadly Sins of Rare Diseases’ column, where we decode the pathogenic
mechanisms of rare diseases, industry research progress (e.g. gene therapy), and innovative pre-clinical
strategies to drive translational research results (such as model construction and drug screening, etc.).
At Cyagen, we are a trusted provider of high-quality synthetic guide molecules used in advanced gene editing applications, supporting researchers throughout the development of innovative cell and gene therapies. In this blog, we will explore what guide molecules are, why their sequences are critical to editing efficiency and specificity, and introduce the different quality grades available—from early-stage discovery to clinical-grade delivery. Read on to discover how we can help accelerate your gene and cell therapy development programs with precision-engineered editing solutions.
Understanding Hotspot Pathogenic Mutations
Gene mutations refer to alterations in the structure or sequence of genetic material, including changes in the order or composition of nucleotide base pairs. These mutations can occur within both coding regions and non-coding regions such as promoters, introns, and splice sites.
One of the key components enabling targeted genome modification is the guide RNA molecule, which plays a critical role in directing editing enzymes to the correct genomic location. A commonly used guide format is the single guide molecule (sGuide Molecule), which can sometimes be confused with the dual-guide configuration, so let’s briefly explain the distinction.
In natural bacterial defense systems, the targeting mechanism involves two separate RNA molecules: one serves as the recognition sequence (~20 nucleotides) that matches the target DNA region, while the other acts as a structural scaffold to facilitate the binding of the complex to the editing enzyme.
The sGuide Molecule is a streamlined, engineered format in which these two RNA components are fused into a single chimeric strand. This single-guide format has become widely adopted in modern gene editing due to its simplicity and ease of customization. While guide molecules can be synthesized in vitro or expressed via plasmid or viral vectors, chemically synthesized single-guide formats typically offer superior editing performance and consistency.
Familial Dysautonomia: ELP1 Intronic Point Mutation
Familial dysautonomia (FD) is a rare inherited condition affecting your nervous system. It
impacts breathing, salivating, forming tears and regulating body temperature and blood pressure. Providers
diagnose FD with specific tests and genetic testing. Treatments include medications, therapy and surgery.
People with FD have shorter life expectancies.
Genetic changes (mutations) cause familial dysautonomia. Both of your parents must carry a
mutation in a gene called ELP1. The ELP1 gene makes a protein that helps your nervous system develop. If
this gene has a mutation, problems occur with parts of your nervous system.
Facioscapulohumeral Muscular Dystrophy: Abnormal DUX4 Expression
Advances in the molecular understanding of facioscapulohumeral muscular dystrophy (FSHD) have
revealed that FSHD results from epigenetic de-repression of the DUX4 gene in skeletal muscle, which encodes
a transcription factor that is active in early embryonic development but is normally silenced in almost all
somatic tissues. These advances also led to the identification of targets for disease-altering therapies for
FSHD, as well as an improved understanding of the molecular mechanism of the disease and factors that
influence its progression. Together, these developments led the FSHD research community to shift its focus
towards the development of disease-modifying treatments for FSHD. This Review presents advances in the
molecular and clinical understanding of FSHD, discusses the potential targeted therapies that are currently
being explored, some of which are already in clinical trials, and describes progress in the development of
FSHD-specific outcome measures and assessment tools for use in future clinical trials.
DUX4, a gene encoding a transcription factor involved in early embryogenesis, is located within the D4Z4
subtelomeric repeat on chromosome 4q35. In most healthy somatic tissues, DUX4 is heavily repressed by
multiple genetic and epigenetic mechanisms, and its aberrant expression is linked to facioscapulohumeral
muscular dystrophy (FSHD) where it has been extensively studied. Recently, DUX4 expression has been
implicated in oncogenesis, although this is much less explored. In this review, we discuss multiple levels
of control of DUX4 expression, including enhancer–promoter interactions, DNA methylation, histone
modifications, noncoding RNAs, and telomere positioning effect. We also connect disparate data on
intrachromosomal contacts involving DUX4 and emphasize the feedback loops in DUX4 regulation. Finally, we
bridge data on DUX4 in FSHD and cancer and discuss prospective approaches for future FSHD therapies and the
potential outcomes of DUX4 inhibition in cancer.
References
[1] Carmel I , Tal S , Vig I ,et al.Comparative analysis detects dependencies among the 5′ splice-site positions[J].RNA, 2004, 10(5):828-840.DOI:10.1261/rna.5196404.
[2] Anderson S L , Coli R , Daly I W ,et al.Familial Dysautonomia Is Caused by Mutations of the IKAP Gene[J].The American Journal of Human Genetics, 2001, 68(3):753-758.DOI:10.1086/318808.
ABOUT THE AUTHOR
Rebecca Roberts, Ph.D.
Rebecca Roberts is a molecular biologist and science writer. She loves demystifying science to the general public and has too many hobbies to be really good at any of them. When she’s not working, you can usually find her in a forest somewhere, drinking coffee, or listening to death metal.
