Hypomyelinating Leukodystrophy-10 Presenting with an Additional Atypical Feature of Increased Body Hair and Mongolian Spots

This case study describes a 3.5-year-old male with hypomyelinating leukodystrophy-10 (HLD10), presenting with global developmental delay, neuroregression, and atypical features such as increased body hair and Mongolian spots. His female sibling showed similar symptoms, excluding hypertrichosis, but had additional brain abnormalities. MRI scans revealed white matter hyperintensities and other brain structure anomalies. Whole-exome sequencing identified a pathogenic variant in the PYCR2 gene, confirming HLD10. This study underscores the importance of exome sequencing in diagnosing rare HLD subtypes with atypical presentations.