Severe Variant of X-Linked Dyskeratosis Congenita (Hoyeraal-Hreidarsson Syndrome) Causes Significant Enterocolitis in Early Infancy

Hoyeraal-Hreidarsson syndrome (HHS) was identified as a severe variant of X-linked dyskeratosis congenita, primarily caused by mutations in the DKC1 gene. This study reported two cases of HHS in infants, highlighting significant gastrointestinal complications, including severe enterocolitis and intractable diarrhea, which often required surgical interventions like ileostomy. The study found that gastrointestinal symptoms, such as oral ulcerations and esophageal dysmotility, were common and often preceded hematological and immunological issues. Despite attempts with various treatments, including high-dose corticosteroids, the gastrointestinal symptoms were challenging to manage, and stem cell transplantation showed no significant improvement. The study emphasized the need to consider HHS in young children presenting with severe gastrointestinal symptoms.