ABOUT THE GRANT

New York’s newborn screening program for Krabbe Disease (KD) tested nearly 2 million infants between 2006 and 2014,
finding five cases of the disease. They also identified babies with lower levels of a key enzyme (GALC) and genetic mutations
that could potentially cause KD, referring these infants for further testing. Of the 348 babies tested, about half had certain genetic
changes term variant of uncertain significance or VUS that are commonly seen in KD: p.T112A, p.Y319C, p.M117V, and p.L634S.
Since KD was recently added to the national screening list, this type of screening will likely expand across the country, meaning
more babies with these and new GALC VUS may be identified in the future. Even though many of these babies with mutations
don’t show any symptoms right away, it’s still unclear what the long-term effects might be, as there’s limited data on how
these genetic changes impact health.

We think that measuring GALC enzyme activity and levels of a toxic substance called psychosine in cells can help
determine whether certain genetic changes cause the disease. To make sure the results are accurate, we plan to set
up a standardized testing system where we can carefully control all the variables. Our research will focus on two main goals:

1. Developing a Standardized Testing System: We want to create a system to accurately measure GALC enzyme activity,
psychosine levels, and other factors in cells. While we’ve already set up some tests, we still need to fine-tune others, like
looking at how GALC is controlled in the cells at RNA level when certain types of mutations are present. This will help
us better understand the disease and test whether certain genetic changes are likely to cause it.

2. Testing 20 Most Common GALC VUS in KD: Using the standardized system, we’ll look at how the 20 most
common genetic changes, which found in New York’s newborn screening program and in probable cases
referred to the Mayo Clinic Clinical Laboratory, affect GALC function and disease development. This will
help us understand whether these GALC VUS will contribute to KD and how soon the carriers will develop disease.

Chris Lee, PhD, is a neuroscientist and molecular biologist whose research focuses on the molecular mechanisms and experimental therapeutics of neurodegenerative diseases. While on faculty as an Assistant Professor at the Mayo Clinic, Dr. Lee initiated his research program on Krabbe Disease (KD). He led studies uncovering how specific genetic mutations in the

GALC gene lead to dysfunction of the galactosylceramidase (GALC) enzyme. His pioneering work has shown that GALC deficiency is mutation-dependent and can result from mechanisms such as nonsense-mediated mRNA decay, protein misfolding, or impaired trafficking.

Since joining the Biomedical Research Institute of New Jersey (BRInj) and Atlantic Health System, as a faculty scientist and a lead researcher, respectively, in 2017, Dr. Lee has expanded his research program with critical support from the Rosenau Family Research Foundation. This funding enabled his team to develop a novel GALC immunoassay, which can detect endogenous GALC protein in human samples. Using this tool, Dr. Lee has demonstrated that GALC protein levels may differentiate infantile- from later-onset KD – a finding published in Neurobiology of Disease.

Dr. Lee’s lab also generated a GALC knockout cell model to functionally evaluate disease- associated GALC mutations. In a recent study, his team characterized 36 missense mutation variants and found a strong correlation between residual GALC activity and clinical disease severity, providing a promising prognostic indicator for KD. This work was recently published in the Journal of Biological Chemistry.

Dr. Lee is now leading a new initiative to assess the pathogenicity of GALC variants of uncertain significance (VUS) – a growing challenge as Krabbe disease has been added to the Recommended Uniform Screening Panel (RUSP) for newborn screening in the U.S. Leveraging his lab’s tools and expertise, this project aims to provide much-needed functional insight to improve prognostication for at-risk infants.