A 37-kb Deletion in Region 16p13.3 in an Infant with Osteopetrosis and Congenital Diarrhea Including the CLCN7 and PERCC1 Genes

Abstract Introduction: Congenital diarrhea presents a diagnostic challenge in cases where standard assessments are inconclusive. Case Presentation: We report a female infant with thrombocytopenia, increased bone density, and pale optic disc symptoms, suggestive of osteopetrosis. However, she also exhibited noninfectious, blood- and mucus-free diarrhea, not accounted for by osteopetrosis. Genetic testing, including clinical exome sequencing and chromosomal microarray analysis, revealed a homozygous 39-kb deletion on chromosome 16p13.3. This deletion spanned the CLCN7 gene associated with osteopetrosis and the PERCC1 gene implicated in congenital diarrhea. Conclusion: This case illustrates the importance of considering 16p13.3 deletions when confronted with the dual presentation of congenital diarrhea and osteopetrosis, expanding the diagnostic considerations for similar clinical presentations. Established FactsHomozygous truncating variants in the CLCN7 gene cause autosomal recessive osteopetrosis.The newly identified PERCC1 gene, which is associated with autosomal recessive congenital diarrhea, is located in the 16p13.3 region in close proximity to the CLCN7.