Orthotopic Liver Transplantation in a Patient With GALT p.Ser135Leu/Null

We report the case of a now 12-year-old male compound heterozygous for a novel GALT null variant and the p.Ser135Leu variant, associated with clinical variant galactosemia. This patient presented with fulminant liver failure at age 2 months requiring liver transplant. Despite initial detection by newborn screening, a misinterpretation of results led to delayed diagnosis and treatment. While the p.Ser135Leu GALT variant is often associated with a milder long-term phenotype, this case highlights that newborns compound heterozygous for p.Ser135Leu and a null variant are at risk of end-stage liver disease if not immediately switched to a low-galactose diet. Surprisingly, despite the transplant with an ostensibly normal liver and continued dietary galactose restriction, this patient continues to show mildly elevated RBC Gal-1-P and urine galactitol.