Successful management of delayed-onset adenosine deaminase deficiency with novel mutation.

A 4-year-old boy presented with acute-onset autoimmune cytopenia with severe, persistent lymphopenia, autoimmune thyroiditis, elevated IgE and glucose 6-phosphate dehydrogenase enzyme deficiency. In immunologic evaluation, lower T, B and natural killer cells and higher levels of adenosine deaminase (ADA) metabolites were observed. The compound heterozygous novel ADA gene mutations causing ADA deficiency were detected. Successful immunologic and metabolic cure was achieved with enzyme replacement therapy, followed by reduced intensity conditioning hematopoietic stem cell transplantation from a matched unrelated donor. An interesting aspect of this patient is the detection of novel compound heterozygous mutations without consanguinity and a secondary outcome is the recovery of glucose 6-phosphate dehydrogenase deficiency after hematopoietic stem cell transplantation.

The importance of skin prick test in differentiating cat sensitivities and allergies in children.

BACKGROUND: The incidence of cat allergies in children has increased over the years. Children with cat allergies have mostly reported respiratory symptoms. The skin prick test (SPT) is the most preferred method to demonstrate sensitization to allergens. However, not all children who develop cat sensitization due to environmental exposure become allergic to cats. In our study, we aimed to determine the frequency of sensitization to cat and cat allergy, cat-related symptoms, and the cut-off value for the SPT that may indicate cat allergy. METHODS: Patients aged 2-18 years, who applied to the Health Sciences University Izmir Dr Behçet Uz Pediatrics and Surgery Training and Research Hospital and Balikesir University Application and Research Hospital Pediatric Allergy outpatient clinics between January 01, 2019 and December 31, 2020, were included in the study. Patients who underwent SPT and found to be sensitized to cat allergen, were evaluated retrospectively. Clinical and laboratory findings of the patients were recorded. Receiver operating characteristics (ROC) analysis was performed to determine the cut-off value for the SPT. RESULTS: Sensitization to cat was detected in 140 (4%) out of 3499 patients who underwent SPT. The median age of the patients was 12 years (min-max: 5-18) and 67.1% were male. Eighty-eight (62.9%) patients were symptomatic upon contact with cats, predominantly with nasal symptoms. These patients had significantly larger cat SPT wheal size than asymptomatic patients. The cut-off value was determined as 5.5 mm with a sensitivity of 72.7% and a specificity of 61.5% (95% CI, 60.5%-78.4%). Symptoms resolved in about half of our patients by reducing contact with cats. DISCUSSION: The present study is the first to report the frequency and clinical findings of cat sensitizations and allergies in Turkish children. For effective treatment, cat allergy must be diagnosed. In this regard, the use of a practical, readily accessible 5.5 mm cut-off point on the SPT may be helpful.

A novel mutation in DNMT3B gene causing ICF1 syndrome in an infant with refractory thrombocytopenia.

BACKGROUND: ICF syndrome is a rare autosomal recessive condition characterized by immunodeficiency, centromeric instability, and facial abnormalities. It is a clinical condition that depends on the mutation of a few particular genes and is caused by methylation disruption in chromosomes 1, 9, and 16 to varying degrees. CASE PRESENTATION: The 9-months old, female patient was admitted to our clinic for treatment-resistant thrombocytopenia, chronic diarrhea and sepsis. Immunological investigations revealed agammaglobulinemia. In the genetic analysis by NGS of the patient, who had dysmorphic facial findings as well as a history of parental consanguinity, it was determined that she had a novel mutation in the DNMT3B gene, which is one of the responsible genes of ICF, as homozygous. The patient, who was started on regular immunoglobulin replacement therapy and antibiotic therapy, was referred to a center with a stem cell transplant unit to continue her follow-up. CONCLUSIONS: Although autoimmunity has not been commonly reported in previous studies in ICF syndrome, which has a varied clinical presentation, a homozygous mutation in the DNMT3B gene was discovered in a 9-month-old patient with refractory thrombocytopenia and agammaglobulinemia. Examining the literature reveals that this mutation is a novel mutation.