OBJECTIVE: To summarize the clinical features and management of two brothers affected with X-linked inhibitor of apoptosis protein (XIAP) deficiency. METHODS: This study retrospectively analyzed the clinical presentations, treatment, and follow-up of two brothers with XIAP deficiency diagnosed at Shanghai Children's Hospital in 2020, and summarized similar cases recorded in databases such as PubMed, Wanfang, Chinese Medical Association Journals, and WIP from January 2006 to November 2024. This study was approved by the Medical Ethics Committee of our hospital (Ethics No.: 2025R128-E01). RESULTS: Patient 1 was the younger brother, who presented at 8 years of age with growth retardation, folliculitis, erythema nodosum, and perineal abscess. Sequencing revealed that he has carried a hemizygous c.566T>C (p.Leu189Pro) variant of the XIAP gene, which was inherited from his mother. He was allergic to infliximab treatment and underwent allogeneic stem cell transplantation (HSCT) in January 2021. During a follow-up of 3 years and 10 months post-transplantation, he showed no gastrointestinal symptoms and had a good outcome. Patient 2 was the elder brother, who presented at 10 years and 6 months of age with growth retardation, rash, and anal fistula. Genetic testing revealed the same variant. He was treated with oral azathioprine but did not have regular follow-ups. At 14-years-and-6-months of age, he had developed severe gastrointestinal infection and hemophagocytic lymphohistiocytosis, which was alleviated after treatment with antibiotics, glucocorticoids, immunoglobulin, and rituximab. He is currently being prepared for HSCT. A total of 13 publications were retrieved, which involved 64 patients from 23 families, with 23 different variants identified. The main clinical manifestations included splenomegaly (34 cases, 53.1%), hemophagocytic lymphohistiocytosis (27 cases, 42.2%), and inflammatory bowel disease or colitis (20 cases, 31.8%). There were significant phenotypic differences among patients from the same family. Thirteen patients (20.3%) underwent HSCT, with a survival rate of 61.5%. CONCLUSION For male children with early onset, poor treatment response, especially those with unexplained splenomegaly and IBD-like symptoms, early genetic testing is recommended. HSCT is a safe and effective treatment for XIAP deficiency. For patients with developmental delay, early onset, and severe IBD phenotype, early transplantation is recommended.
Humans ; Male ; X-Linked Inhibitor of Apoptosis Protein/deficiency* ; Child ; Genetic Diseases, X-Linked/therapy* ; Phenotype ; Siblings ; Retrospective Studies ; Hematopoietic Stem Cell Transplantation

BACKGROUND/AIMS: The aim of this study was to identify the profile of rare variants associated with Crohn's disease (CD) using whole exome sequencing (WES) analysis of Korean children with CD and to evaluate whether genetic profiles could provide information during medical decision making. METHODS: DNA samples from 18 control individuals and 22 patients with infantile, very-early and early onset CD of severe phenotype were used for WES. Genes were filtered using panels of inflammatory bowel disease (IBD)-associated genes and genes of primary immunodeficiency (PID) and monogenic IBD. RESULTS: Eighty-one IBD-associated variants and 35 variants in PID genes were revealed by WES. The most frequently occurring variants were carried by nine (41%) and four (18.2%) CD probands and were ATG16L2 (rs11235604) and IL17REL (rs142430606), respectively. Twenty-four IBD-associated variants and 10 PID variants were predicted to be deleterious and were identified in the heterozygous state. However, their functions were unknown with the exception of a novel p.Q111X variant in XIAP (X chromosome) of a male proband. CONCLUSIONS: The presence of many rare variants of unknown significance limits the clinical applicability of WES for individual CD patients. However, WES in children may be beneficial for distinguishing CD secondary to PID.
Asian Continental Ancestry Group/genetics ; Carrier Proteins/genetics ; Child ; Child, Preschool ; Crohn Disease/*genetics ; *Exome ; Female ; Genetic Predisposition to Disease ; *Genetic Variation ; Humans ; Immunologic Deficiency Syndromes/genetics ; Infant ; Male ; Phenotype ; Receptors, Interleukin-17/genetics ; Republic of Korea ; Sequence Analysis, DNA/*methods ; X-Linked Inhibitor of Apoptosis Protein/genetics

Amino Acid Sequence ; Base Sequence ; Child ; Flow Cytometry ; methods ; Genes, X-Linked ; Hematopoietic Stem Cell Transplantation ; Humans ; Lymphocytes ; metabolism ; Lymphohistiocytosis, Hemophagocytic ; diagnosis ; genetics ; therapy ; Lymphoproliferative Disorders ; diagnosis ; genetics ; therapy ; Mutation ; Transplantation, Homologous ; X-Linked Inhibitor of Apoptosis Protein ; deficiency ; genetics ; metabolism