# Massively-parallel functional interrogation of genetic variation in CMD-associated alpha-dystroglycan glycosylating enzymes

> **NIH NIH R01** · WASHINGTON UNIVERSITY · 2024 · $349,249

## Abstract

PROJECT SUMMARY
Mutations in genes that glycosylate alpha-dystroglycan (α-DG) are frequent causes of a spectrum of muscle
disease ranging from congenital muscular dystrophy (CMD) to childhood and adult onset limb-girdle muscular
dystrophy (LGMD). These devasting myopathies are deemed dystroglycanopathies and cause muscle wasting,
progressive weakness, and degeneration of skeletal muscle leading to loss of ambulation, difficulties in
breathing and premature death. The α-DG glycosyltransferase genes include, among others, FKTN, FKRP,
POMT1, POMT2, and POMGNT1 and together account for >50% of genetically diagnosed CMD/LGMD.
Accurately diagnosing patients with CMD or LGMD before symptom onset or early in the course of the disease
has the potential to enable the use of preventative gene therapy or other therapeutics and in most cases can
only be done through genetic testing in pre-symptomatic individuals or prenatally. When a new DNA variant in
one of these genes is observed in a patient, however, there is often insufficient evidence to classify it as
pathogenic. Within this study, we will use a new approach to express and characterize every possible
missense variant in the assessed genes to advance our understanding of dystroglycan biology, improve the
interpretation of genetic variation in dystroglycanopathy genes, and advance CMD/LGMD care and treatments.
We will employ deep mutational scanning, a method for measuring the effects of massive numbers of
missense variants of a protein simultaneously. Further, as only a subset of CMD and LGMD patients have
potentially pathogenic variants in known muscular dystrophy genes, we will perform CRISPR screens in
different cellular contexts to identify genes contributing to abnormal alpha-dystroglycan function. Our two aims
are: 1) Quantifying the effect of nearly every possible missense variant in FKTN, FKRP, POMT1, POMT2, and
POMGNT1 on protein stability, alpha-dystroglycan glycosylation and cellular adhesion and 2) Perform in-depth
analysis of dystroglycanopathy patient variants integrating multiple in vitro assays, clinical information and
patient specimen biochemical analysis to validate our DMS approach and disseminate pathogenicity
predictions. The functional data we generate, the analyses we propose, and tools we build will transform the
characterization of dystroglycanopathy gene variants. They will also serve as a resource to better understand
muscle biology, improve the clinical translation of dystroglycanopathies and CMD/LGMD using genetic
information, and inform new treatments.

## Key facts

- **NIH application ID:** 10936537
- **Project number:** 5R01AR081901-02
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** Gabriel E Haller
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $349,249
- **Award type:** 5
- **Project period:** 2023-09-26 → 2028-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10936537

## Citation

> US National Institutes of Health, RePORTER application 10936537, Massively-parallel functional interrogation of genetic variation in CMD-associated alpha-dystroglycan glycosylating enzymes (5R01AR081901-02). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10936537. Licensed CC0.

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