Allogeneic hematopoietic stem cell transplantation in two brothers with DNA ligase IV deficiency: a case report and review of the literature

Allogeneic hematopoietic stem cell transplantation corrects ligase IV deficiency

BACKGROUND

Mutations in the DNA ligase IV (LIG4) gene cause a rare autosomal recessive disorder called LIG4 deficiency syndrome. The LIG4 deficiency is featured by severe disorders, including combined immunodeficiency disease, special face ("bird-head-like" face), developmental delays, pancytopenia, and radiosensitivity. Currently there are no curative treatment options except potentially by performing a hematopoietic stem cell transplantation (HSCT).

CASE PRESENTATION

Here we reported the clinical course of a 4 and 1/2-year-old Chinese female with LIG4-deficiency featured with pancytopenia, severe growth retardation (weight of 13.5 kg, < 3rd percentile), length of 100 cm (<2d percentile), head circumference of 46 cm (<3rd percentile), and mild microcephaly. Despite regular IVIG administrations (5 g, once a month), the patient's thrombocytopenia had progressed. Eventually, the patient received HSCT that successfully normalized the LIG4 syndrome associated pancytopenia and corrected the LIG4 mutation. Despite progress the patient succumbed to thrombotic microangiopathy more than 3 months after HSCT.

CONCLUSIONS

This case reports an example of partially successful HSCT as a treatment option for LIG4 syndrome. It is possible that individual factors influence the therapeutic effect of HSCT in LIG4 deficiency.

Autoimmunity and immunodeficiency associated with monoallelic LIG4 mutations via haploinsufficiency

BACKGROUND

Biallelic mutations in LIG4 encoding DNA-ligase 4 cause a rare immunodeficiency syndrome manifesting as infant-onset life-threatening and/or opportunistic infections, skeletal malformations, radiosensitivity and neoplasia. LIG4 is pivotal during DNA repair and during V(D)J recombination as it performs the final DNA-break sealing step.

OBJECTIVES

This study explored whether monoallelic LIG4 missense mutations may underlie immunodeficiency and autoimmunity with autosomal dominant inheritance.

METHODS

Extensive flow-cytometric immune-phenotyping was performed. Rare variants of immune system genes were analyzed by whole exome sequencing. DNA repair functionality and T-cell-intrinsic DNA damage tolerance was tested with an ensemble of in vitro and in silico tools. Antigen-receptor diversity and autoimmune features were characterized by high-throughput sequencing and autoantibody arrays. Reconstitution of wild-type versus mutant LIG4 were performed in LIG4 knockout Jurkat T cells, and DNA damage tolerance was subsequently assessed.

RESULTS

A novel heterozygous LIG4 loss-of-function mutation (p.R580Q), associated with a dominantly inherited familial immune-dysregulation consisting of autoimmune cytopenias, and in the index patient with lymphoproliferation, agammaglobulinemia, and adaptive immune cell infiltration into nonlymphoid organs. Immunophenotyping revealed reduced naive CD4+ T cells and low TCR-Vα7.2+ T cells, while T-/B-cell receptor repertoires showed only mild alterations. Cohort screening identified 2 other nonrelated patients with the monoallelic LIG4 mutation p.A842D recapitulating clinical and immune-phenotypic dysregulations observed in the index family and displaying T-cell-intrinsic DNA damage intolerance. Reconstitution experiments and molecular dynamics simulations categorize both missense mutations as loss-of-function and haploinsufficient.

CONCLUSIONS

This study provides evidence that certain monoallelic LIG4 mutations may cause human immune dysregulation via haploinsufficiency.

Mismatched Unrelated Donor Hematopoietic Stem Cell Transplantation Rescues Marrow Failure From Acute Leukemia Therapy in a Patient With Previously Undiagnosed Ligase IV Syndrome

Patients with DNA double-strand breakage repair disorders are at increased risk of malignancy which is often difficult to treat given underlying sensitivity to chemotherapy and radiotherapy, lending an important role to hematopoietic stem cell transplantation. The choice of conditioning regimen used must balance reducing risk of rejection with minimizing excessive toxicity from myeloablative chemotherapy or ionizing radiation. We describe successful engraftment following a nonmyeloablative hematopoietic stem cell transplantation in a patient with Ligase IV syndrome and numerous pretransplant complications including malignancy, cardiac failure, and secondary hemophagocytic lymphohistiocytosis. Congruent with prior reports, a reduced intensity regimen appears efficacious in Ligase IV syndrome patients.

DNA ligase IV dificiency with elevated serum IgG levels suspected to have myelodysplastic syndrome: a case report

BACKGROUND

Ligase IV (LIG4) dificiency is a very rare clinical syndrome with around 50 cases reported to date. This syndrome is caused by biallelic pathogenic variants in the LIG4 gene, which cause DNA damage repair disorders, mainly manifesting as severe immunodeficiency.

CASE PRESENTATION

We report the case of a 15-month-old male child with pancytopenia, growth retardation, microcephaly, history of vaccine-related rubella, elevated immunoglobulin G, and decreased T- and B lymphocytes. Next-generation sequencing revealed LIG4 pathogenic genes and compound heterozygous mutations, namely the missense mutation c.833G > T (p.Arg278Leu) and deletion mutation c.1271_1275del (p.Lys424Argfs*20).

CONCLUSION

This case suggests that LIG4 dificiency can manifest not only as immunodeficiency but also with increased serum IgG levels and pancytopenia, which constitutes an additional clinical phenotype. Furthermore, this case suggests that LIG4 deficiency should be considered upon differential diagnosis of myelodysplastic syndrome in children.

Case Report: Wide Spectrum of Manifestations of Ligase IV Deficiency: Report of 3 Cases

DNA ligase IV deficiency is a rare autosomal recessive disorder associated with impaired DNA repair mechanisms. Most patients with DNA repair defects present with neurologic deficits, combined immunodeficiency, bone marrow failure, and/or hematologic neoplasia. We present 3 unrelated cases of ligase IV deficiency with different clinical presentations. Patient 1 presented at the age of 5 with bone marrow failure, dysmorphic features, and T and B lymphopenia. A compound heterozygous variant L19W/K635fs in the LIG4 gene was identified. Patient 2 presented at the age of 16 with recurrent infections. He had agammaglobulinemia and absent B cells. A homozygous R278H in the LIG4 gene was identified. Patient 3 was referred for vitiligo and B-cell lymphopenia (low class-switched B cells) and hypogammaglobulinemia. Homozygous R278H in LIG4 was also identified. In the last few years, the spectrum of clinical manifestations caused by ligase IV deficiency has widened, making it very difficult to establish an accurate clinical diagnosis. The use of NGS allows a proper diagnosis and provides a better prognosis and adequate family counseling.

Characterization of a Cohort of Patients With LIG4 Deficiency Reveals the Founder Effect of p.R278L, Unique to the Chinese Population

DNA ligase IV (LIG4) deficiency is an extremely rare autosomal recessive primary immunodeficiency disease caused by mutations in LIG4. Patients suffer from a broad spectrum of clinical problems, including microcephaly, growth retardation, developmental delay, dysmorphic facial features, combined immunodeficiency, and a predisposition to autoimmune diseases and malignancy. In this study, the clinical, molecular, and immunological characteristics of 15 Chinese patients with LIG4 deficiency are summarized in detail. p.R278L (c.833G>T) is a unique mutation site present in the majority of Chinese cases. We conducted pedigree and haplotype analyses to examine the founder effect of this mutation site in China. This suggests that implementation of protocols for genetic diagnosis and for genetic counseling of affected pedigrees is essential. Also, the search might help determine the migration pathways of populations with Asian ancestry.

Correction to: Allogeneic hematopoietic stem cell transplantation in two brothers with DNA ligase IV deficiency: a case report and review of the literature

After publication of the original article (1), it was brought to our attention that references 24 and 31 are inappropriately cited in the article.