Novel CARMIL2 (RLTPR) Mutation Presenting with Hyper-IgE and Eosinophilia: A Case Report

BACKGROUND

Inborn errors of immunity are a growing group of disorders with a wide spectrum of genotypic and phenotypic profiles. CARMIL2 (previously named RLTPR) deficiency is a recently described cause of immune dysregulation, mainly presenting with allergy, mucocutaneous infections, and inflammatory bowel disease. CARMIL2 deficiency is categorized under diseases of immune dysregulation with susceptibility to lymphoproliferative conditions.

CASE PRESENTATION

Here we describe a 29-years-old male from a consanguineous family, with food and sting allergy, allergic rhinitis, facial molluscum contagiosum (viral infection of the skin in the form of umbilicated papules), eosinophilia and highly elevated serum IgE level. Whole exome sequencing revealed numerous homozygous variants, including a CARMIL2 nonsense mutation, a gene regulating actin polymerization, and promoting cell protrusion formation.

CONCLUSION

The selective role of CARMIL2 in T cell activation and maturation through cyto-skeletal organization is proposed to be the cause of immune dysregulation in individuals with CARMIL2 deficiency. CARMIL2 has an important role in immune pathways regulation, through cell maturation and differentiation, giving rise to a balance between Th1, Th2, and Th17 immune response. This case can improve the understanding of the different impacts of CARMIL2 mutations on immune pathways and further guide the diagnosis of patients with similar phenotypes.

Case Report: Refractory Cytopenia With a Switch From a Transient Monosomy 7 to a Disease-Ameliorating del(20q) in a NHEJ1-Deficient Long-term Survivor

We report the case of a male Pakistani patient with a pathogenic homozygous loss of function variant in the non-homologous end-joining factor 1 (NHEJ1) gene. The growth retarded and microcephalic boy with clinodactyly of both hands and hyperpigmentation of the skin suffered from recurrent respiratory infections. He was five and a half years old when he came to our attention with refractory cytopenia and monosomy 7. Hematopoietic stem cell transplantation was considered but not feasible because there was no suitable donor available. Monosomy 7 was not detected anymore in subsequent bone marrow biopsies that were repeated in yearly intervals. Instead, seven and a half years later, a novel clone with a del(20q) appeared and steadily increased thereafter. In parallel, the patient’s blood count, which had remained stable for over 20 years without necessitating any specific therapeutic interventions, improved gradually and the erythropoiesis-associated dysplasia resolved.

BCGitis as the primary manifestation of chronic granulomatous disease

Patients with primary immunodeficiency disease (PID) are not only vulnerable to mycobacterial disease, but are also more likely to develop adverse events following BCG vaccination. These events can range from regional disease (BCGitis) to disseminated disease (BCGosis). Chronic granulomatous disease (CGD), which is characterized by impaired leukocyte phagocytic function, is one of the many inherited PIDs that increase the body's susceptibility to recurrent bacterial and fungal infections. Here, we report a 6-year-old boy with no significant past medical history who presented with progressive lymphadenopathy six years after BCG vaccination. He was later diagnosed with CGD on further evaluation.

Targeted mutation screening of 292 candidate genes in 38 children with inborn haematological cytopenias efficiently identifies novel disease-causing mutations

Establishing a precise diagnosis is essential in inborn haematological cytopenias to enable appropriate treatment decisions and avoid secondary organ damage. However, both diversity and phenotypic overlap of distinct disease entities may make the identification of underlying genetic aetiologies by classical Sanger sequencing challenging. Instead of exome sequencing, we established a systematic next generation sequencing‐based panel targeting 292 candidate genes and screened 38 consecutive patients for disease‐associated mutations. Efficient identification of the underlying genetic cause in 17 patients (44·7%), including 13 novel mutations, demonstrates that this approach is time‐ and cost‐efficient, enabling optimal management and genetic counselling.