Novel DNMT3B Mutation in a Patient with Immunodeficiency, Centromeric Instability, and Facial Anomalies (ICF) Syndrome and a Bronchopulmonary Collateral Artery

Bridging the gap: neurodevelopmental disorder risks in inborn errors of immunity

PURPOSE OF REVIEW

The aim of this review is to examine published reports of neurodevelopmental phenotypes in patients with inborn errors of immunity (IEI). We briefly discuss potential interactions between the immune and the central nervous system and the implications of this crosstalk for current clinical management guidelines.

RECENT FINDINGS

An increasing number of reports have described neurodevelopmental disorders (NDDs) comorbid with immune-mediated signs. However, the prevalence of this association in IEIs remains unknown.

SUMMARY

IEIs comprise a group of clinically heterogeneous disorders associated with a number of nonimmune comorbidities. Although certain neurological conditions such as microcephaly are recognized as associated features of some IEIs, NDDs are less well described. We reviewed published clinical descriptions of IEIs and found a number of comorbid NDDs in these patients, including autism spectrum disorder (ASD), behavioral deficits, and intellectual disability. Given the lack of uniform assessments for NDDs, we suspect they may be underdiagnosed in IEIs. As NDDs manifest early and can result in life-long cognitive and emotional deficits, which diminish quality of life and increase healthcare utilization, we hope to elucidate relevant pathomechanisms and raise clinician awareness of these comorbidities so appropriate and timely interventions are sought.

DNMT1 Y495C mutation interferes with maintenance methylation of imprinting control regions

Hereditary Sensory and Autonomic Neuropathy Type 1E (HSAN1E) is a rare autosomal dominant neurological disorder due to missense mutations in DNA methyltransferase 1 (DNMT1). To investigate the nature of the dominant effect, we compared methylomes of transgenic R1wtDnmt1 and R1Dnmt1Y495C mouse embryonic stem cells (mESCs) overexpressing WT and the mutant mouse proteins respectively, with the R1 (wild-type) cells. In case of R1Dnmt1Y495C, 15 out of the 20 imprinting control regions were hypomethylated with transcript level dysregulation of multiple imprinted genes in ESCs and neurons. Non-imprinted regions, minor satellites, major satellites, LINE1 and IAP repeats were unaffected. These data mirror the specific imprinting defects associated with transient removal of DNMT1 in mESCs, deletion of the maternal-effect DNMT1o variant in preimplantation mouse embryos, and in part, reprogramming to naïve human iPSCs. This is the first DNMT1 mutation demonstrated to specifically affect Imprinting Control Regions (ICRs), and reinforces the differences in maintenance methylation of ICRs over non-imprinted regions. Consistent with nervous system abnormalities in the HSAN1E disorder and involvement of imprinted genes in normal development and neurogenesis, R1Dnmt1Y495C cells showed dysregulated pluripotency and neuron marker genes, and yielded more slender, shorter, and extensively branched neurons. We speculate that R1Dnmt1Y495C cells produce predominantly dimers containing mutant proteins, leading to a gradual and specific loss of ICR methylation during early human development.

Thymus as Incontrovertible Target of Future Immune Modulatory Therapeutics

Thymus plays a crucial role in cellular immunity by acting as a warehouse for proliferating and differentiating lymphocytes. Thymic stromal cells educate T-cells to differentiate self from non-self antigens while nurse cells and thymoproteasome play a major role in the maturation and differentiation of T-cells. The thymic conditions dictate T-cells to cope with the risk of cancer development. A study was designed to demonstrate potential mechanisms behind the failure to eliminate tumors and impaired immune surveillance as well as the impact of delay in thymus regression on cancer and autoimmune disorders. Scientific literature from Pubmed; Scopus; WOS; JSTOR; National Library of Medicine Bethesda, Maryland; The New York Academy of Medicine; Library of Speech Rehabilitation, NY; St. Thomas' Hospital Library; The Wills Library of Guys Hospital; Repository of Kings College London; and Oxford Academic repository was explored for pathological, physiological, immunological and toxicological studies of thymus. Studies have shown that systemic chemotherapy may lead to micro inflammatory environment within thymus where conventionally and dynamically metastasized dormant cells seek refuge. The malfunctioning of the thymus and defective T and Treg cells, bypassing negative selection, contributes to autoimmune disorders, while AIRE and Fezf2 play significant roles in thymic epithelial cell solidity. Different vitamins, TCM, and live cell therapy are effective therapeutics. Vitamin A, C, D, and E, selenium and zinc, cinobufagin and dietary polysaccharides, and glandular extracts and live cell injections have strong potential to restore immune system function and thymus health. Moreover, the relationship between different ages/ stages of thymus and their corresponding T-cell mediated anti-tumor immune response needs further exploration.