Congenital Nystagmus (CN)

Congenital nystagmus is a heterogeneous condition with a prevalence ranging from 14 to 6.1 per 10,000 live births. Protheragen is at the forefront of congenital nystagmus research, offering comprehensive diagnostics and therapeutics development services.

Overview of Congenital Nystagmus (CN)

Congenital nystagmus (CN) alludes to a complex ocular disorder associated with an involuntary, rhythmic oscillation movement of the eyes. Generally noticed in the first couple months of life, CN has the potential to disrupt visual acuity and quality of life significantly. The condition is often subdivided into two broad categories; sensory nystagmus which forms part of the visual pathway abnormalities, and motor nystagmus which results from the dysfunction of the ocular motor system. The causes of CN are multi-dimensional, ranging from genetic to visual pathway and ocular motor pathway disruptions. It is important to understand these mechanisms for the purposes of developing effective diagnostic and therapeutic approaches.

Fig.1 Classification of the different forms of childhood nystagmus. (Hussain N., 2016)

Diagnostics Development for Congenital Nystagmus

Therapeutics Development for Congenital Nystagmus

Congenital nystagmus drugs administered aim at relieving the symptoms, increasing the vision capability of the patient, and diminshing the nystagmus oscillations. Human trials have been conducted with memantine and gabapentin with some success in blunting the nystagmus oscillations. Memantine, an NMDA antagonist, has been shown to decrease the frequency of nystagmus motion and improve vision for some cases. An anticonvulsant gabapentin is another medication that has been implemented which has shown an improvement in nystagmus’s intensity but does so with mixed results.

Our Services

Protheragen is focused on the research and development of therapeutics for congenital nystagmus (CN). We combine molecular diagnostics, preclinical research and therapeutic development, using cutting-edge technologies and a multidisciplinary approach to provide innovative solutions for this complex and challenging disease.

CN Target Identification and Validation Services

Protheragen provides comprehensive target identification and validation services to help clients identify novel molecular targets for CN therapy, leveraging advances in genetic sequencing, transcriptomics, and proteomics. Our services include in silico analysis of CN-associated genetic variants, using proprietary databases and bioinformatics tools to prioritize candidate genes and pathways involved in CN pathogenesis. We conduct in vitro validation studies using primary ocular cells, including retinal neurons, oculomotor neurons, and glial cells, to assess the functional role of candidate targets in regulating ocular motility and visual function. For example, we can evaluate the expression and activity of target proteins in cells derived from CN animal models or human induced pluripotent stem cells (iPSCs), providing critical insights into their potential as therapeutic targets.

Additionally, Protheragen offers in vivo target validation using our panel of CN animal models. We assess the impact of target modulation—via gene silencing, overexpression, or pharmacological inhibition—on nystagmus severity, visual acuity, and ocular motor function. Outcome measures include high-speed video recording of eye movements, Teller Acuity Testing (TAT) for visual acuity assessment, and measurement of the Expanded Nystagmus Acuity Function (NAfx), which provides an objective assessment of best potential visual acuity based on foveation duration and accuracy. These studies enable clients to confirm the relevance of candidate targets and prioritize those with the greatest therapeutic potential.

CN Preclinical Efficacy Testing Services

Protheragen delivers rigorous preclinical efficacy testing services to evaluate the therapeutic potential of candidate drugs and therapies for CN. Our efficacy studies are designed to assess the ability of test compounds to reduce nystagmus amplitude and frequency, improve gaze stability, and enhance visual function in validated CN animal models. We utilize a range of state-of-the-art techniques to quantify treatment effects, including infrared reflection and high-speed video recording for precise measurement of eye movements, electroretinography (ERG) to assess retinal function, and behavioral tests to evaluate visual performance.

For small molecule therapies, we conduct dose-response studies to determine the optimal therapeutic dose, onset of action, and duration of effect, using routes of administration relevant to CN therapy (e.g., topical, intravitreal, or systemic). For gene therapies, we evaluate the efficiency of gene delivery to target tissues (e.g., retina, oculomotor nuclei), transgene expression levels, and long-term therapeutic effects on nystagmus and visual function—building on findings from preclinical studies that have demonstrated significant reductions in CN severity following successful gene therapy in RPE65-deficient canines. We also assess combination therapies, evaluating the synergistic effects of multiple compounds or approaches to maximize therapeutic benefit.

CN Preclinical Safety and Toxicology Testing Services

Safety and toxicology testing is a critical component of CN preclinical development, and Protheragen offers comprehensive services to evaluate the safety profile of candidate therapies. Our services include GLP-compliant toxicology studies, assessing both ocular and systemic toxicity following administration of test compounds. Ocular toxicity evaluations include slit-lamp biomicroscopy, fundus photography, and histopathological analysis of ocular tissues (e.g., cornea, retina, optic nerve) to detect signs of irritation, inflammation, or tissue damage. Systemic toxicity assessments include clinical observations, body weight monitoring, hematological and biochemical analysis, and histopathological evaluation of major organs.

We also conduct safety pharmacology studies to evaluate the effects of candidate therapies on cardiovascular, respiratory, and central nervous system function—critical considerations for CN therapies, which may target neural pathways involved in multiple physiological processes. Additionally, we assess immunogenicity for biologic and gene therapies, evaluating the host immune response to therapeutic agents to identify potential adverse reactions. Our safety testing services are tailored to the specific characteristics of each candidate therapy, ensuring that clients receive comprehensive data to support regulatory submissions and clinical trial design.

CN Pharmacokinetic (PK) and Pharmacodynamic (PD) Testing Services

Protheragen provides detailed pharmacokinetic and pharmacodynamic testing services to characterize the absorption, distribution, metabolism, and excretion (ADME) of candidate CN therapies, as well as their pharmacological effects on target pathways and physiological endpoints. Our PK studies utilize sensitive analytical techniques, including liquid chromatography-tandem mass spectrometry (LC-MS/MS) and enzyme-linked immunosorbent assay (ELISA), to quantify drug concentrations in plasma, ocular tissues (e.g., retina, vitreous humor, cornea), and other relevant biological matrices.

We evaluate key PK parameters, including bioavailability, half-life, clearance, and tissue distribution, to optimize drug formulation and dosing regimens. For PD studies, we correlate drug exposure with therapeutic effects (e.g., reduction in nystagmus amplitude, improvement in visual acuity) and biomarker expression, providing critical insights into the relationship between drug concentration and efficacy. These studies enable clients to refine their therapeutic candidates, ensuring optimal pharmacokinetic properties and maximizing therapeutic efficacy while minimizing potential toxicity.

CN Animal Model Development and Characterization Services

Protheragen offers customized CN animal model development and characterization services to support clients with unique research needs. While we maintain a panel of validated CN models (e.g., RPE65-deficient canines, zebrafish bel mutants), we can also develop novel models tailored to specific CN subtypes or genetic mutations. Our model development services include genetic engineering (e.g., CRISPR/Cas9-mediated gene editing) to generate rodent models carrying human CN-associated mutations, as well as phenotypic characterization to confirm the presence of CN-like symptoms.

Characterization studies include detailed analysis of eye movements using high-speed video recording and infrared tracking, visual acuity assessment via TAT or optokinetic response (OKR) testing, and molecular characterization of target genes and pathways. We also validate model reproducibility and responsiveness to known therapeutic interventions, ensuring that the models are suitable for preclinical efficacy and safety testing. By developing and characterizing robust CN animal models, Protheragen enables clients to advance their research with confidence, knowing that their preclinical data is relevant to human disease.

Diagnostics Development

• Karyotype Analysis Service
• Omics Analysis Service
• Biomarker Development Service
• Artificial Intelligence Service
• Customized Diagnostics Development

Therapeutic Development

• Small Molecule Drug
• Cell Therapy
• Gene Therapy
• Therapeutic Antibody
• Therapeutic Peptide
• Therapeutic Protein
• Customized Therapy Development

Preclinical Research

• Pharmacodynamics Study Services
• Pharmacokinetics Study Services
• Drug Safety Evaluation Services

Disease Models of Congenital Nystagmus

• In Vitro Models and Cell-Based Assays
  In Protheragen's preclinical research services, we provide a wide variety of in vitro models and cell-based assays for studying the molecular mechanisms of congenital nystagmus. Our modern facilities incorporate retinal cell cultures combined with organoid tissues which enables us to perform studies on gene action, protein binding, and cellular signaling. These models enable us to evaluate the effects of pharmacological agents and gene therapy in a controlled system to gain invaluable information for future in vivo experimentation.
• In Vivo Models and Animal Studies
  Our preclinical studies also incorporate techniques such as mouse models for congenital nystagmus to assess therapeutic interventions in vivo. These models permit evaluation of efficacy, safety, and pharmacokinetics. Protheragen's extensive experience in animal studies guarantees accurate experimental setup and analysis, which is critical for translating therapies into human trials.

  -Albino Mouse Models
  -Nyxnob Mouse Models

  -Congenital Stationary Night Blindness (CSNB) Mouse Models

  -Achiasmatic Belgian Sheepdog Models

Protheragen offers customized therapy development services tailored to the unique needs of congenital nystagmus research. If you are interested in our services, please feel free to contact us.

Reference

• Hussain, Nahin. "Diagnosis, assessment, and management of nystagmus in childhood." Paediatrics and Child Health 26.1 (2016): 31-36.