A Systematic Review of Mendelian Pyoderma Gangrenosum: Clinical and Genetic Characteristics in 120 Published Patients

Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis characterised by sterile, recurrent ulcers with a predominantly multifactorial aetiology. However, in a small subset of patients carrying highly penetrant Mendelian mutations in single genes, PG presents as a part of a genetic syndrome. This study aimed to systematically review Mendelian susceptibilities to PG and summarise the clinical and genetic characteristics of patients. Search criteria encompassed case reports, case series and other original articles focusing on causal sequence variants associated with PG pathogenicity. We screened 1577 articles and selected 79 studies, encompassing 120 PG patients and 19 distinct genes, for quantitative analysis. The most prevalent mode of inheritance was autosomal dominant, and the mean age of onset was 23.39 ± 19.76 years. Seventeen of 19 genes are categorised under the Inborn Errors of Immunity (IEI) compiled by the International Union of Immunological Societies (IUIS). According to this, the most reported genes (37%) belong to 'Autoinflammatory Disorders.' All 19 genes were linked to cutaneous ulcers, with PSTPIP1 and MEFV being the only genes associated with all three lesion types (cutaneous, anogenital, mucosal). PSTPIP1 was the most frequently reported PG-related gene, followed by MEFV, ITGB2, NOD2, NFKB1, RAG1, JAK2, and NCSTN. Pseudomonas aeruginosa was the most frequently identified infectious agent in PG skin lesions. This study identifies at least 19 genes associated with PG susceptibility, emphasising the crucial role of genetic factors in disease pathogenesis. Gaining insight into the genetic basis and molecular mechanisms involved may facilitate the development of more targeted therapeutic strategies for PG.

A novel ITGB2 variant in a patient with severe recurrent pyoderma gangrenosum-like lesions and underlying leukocyte adhesion deficiency type I: case report and literature review

Leukocyte adhesion deficiency (LAD) is a group of inborn errors of immunity caused by mutations of integrin subunit b2 gene (ITGB2). Pyoderma gangrenosum (PG) is an uncommon neutrophilic dermatosis characterized by recurrent, sterile, and enlarging necrotic ulcers which may manifest as a single or multiple new lesions simultaneously. Here we report a 43-year-old woman from a consanguine marriage who was diagnosed with LAD-I in childhood, recurrent severe PG-like lesion, and atypical manifestations including celiac disease and low CD19 B-cell subsets. A targeted genetic panel revealed a novel homozygous missense variant c.988T>C (Tyr330His) in ITGB2 gene. While the treatment with prednisolone, cyclosporine, and antibiotics led to partial improvement, the patient unfortunately discontinued the therapy and later died from septicemia. Early hematopoietic cell transplantation (HCT) shortly after birth can be highly effective in managing patients with LAD and preventing life-threatening infections. However, evidence suggests that HCT does not prevent autoinflammatory and autoimmune disorders such as PG. Therefore, it is important to monitor LAD patients for the potential development of PG, even after HCT.

Human Inborn Errors of Immunity in Pyoderma Gangrenosum: A Systematic Review

BACKGROUND AND OBJECTIVE

Pyoderma gangrenosum (PG) is a rare ulcerative neutrophilic dermatosis that can be associated with primary immunodeficiency. The pathogenesis of PG has not yet been elucidated, although contributions from dysregulation of the immune system in patients with apparent genetic predispositions have been postulated. We conducted a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-guided systematic review with the objective of identifying inborn errors of immunity in the presence of PG as well as their clinical characteristics of severity including number of PG lesions and anatomic areas affected, and treatment outcomes.

METHODS

A literature search was performed using PubMed/MEDLINE, Embase, Cochrane Library, and Web of Science through August 24, 2023, for studies published in English using the search terms: "pyoderma gangrenosum," "inborn error of immunity," "immune defect*," and a list of genetic mutations potentially associated with PG.

RESULTS

Seventy-four cases of PG associated with inborn errors of immunity were identified. The results demonstrate an association of PG with a variety of inborn errors of immunity, including genetic mutations not classically associated with the condition. Genetic mutations such as BTK, IL1RN, ITGB2, LPIN2, MEFV, NFkB1, NLRP3, NLRP12, NOD2, PSMB8, PLCG2, PSTPIP1, RAG1, TTC37, and WDR1, as well as complement component 2/complement component 4 (C2/C4) and complement component 7 (C7) deficiencies were identified in the presence of either idiopathic or syndromic PG. Of note, mutations in genes such as PSMB8, NLRP3, and IL1RN were found to be associated with a more severe and atypical course of PG, whereas mutations in RAG1 as well as those causing a C2/C4 deficiency were associated with the mildest clinical presentations of PG. Mutations in NFkB1, ITGB2, and PSTPIP1 were associated with the most heterogeneous clinical presentations.

CONCLUSIONS

Human inborn errors of immunity may be implicated in the genetic predisposition to PG and may influence the clinical presentation. Due to the rarity of these diseases, further work must be done to describe the association between inborn errors of immunity and PG. Identifying inborn errors of immunity that may contribute to the development of PG may assist in further elucidating the mechanism of PG, guiding targeted treatment, and improving clinical outcomes for these patients.

Analysis of Clinical, Immunological and Molecular Features of Leukocyte Adhesion Deficiency Type I in Egyptian Children

PURPOSE

Leukocyte adhesion deficiency (LAD) represents a rare group of inherited inborn errors of immunity (IEI) characterized by bacterial infections, delayed umbilical stump separation, and autoimmunity. This single-center study aimed at describing the clinical, immunological, and molecular characterizations of 34 LAD-I Egyptian pediatric patients.

METHODS

Details of 34 patients' personal medical history, clinical and laboratory findings were recorded; Genetic material from 28 patients was studied. Mutational analysis was done by Sanger sequencing.

RESULTS

Omphalitis, skin and soft tissue infections with poorly healing ulcers, delayed falling of the umbilical stump, and recurrent or un-resolving pneumonia were the most common presentations, followed by chronic otitis media, enteropathy, periodontitis; and recurrent oral thrush. Persistent leukocytosis and neutrophilia were reported in all patients, as well as CD18 and CD11b deficiency. CD18 expression was < 2% in around 90% of patients. Sixteen different pathological gene variants were detected in 28 patients who underwent ITGß2 gene sequencing, of those, ten were novel and six were previously reported. Three families received a prenatal diagnosis. Patients were on antimicrobials according to culture's results whenever available, and on prophylactic Trimethoprim-Sulfamethoxazole 5 mg/kg once daily, with regular clinical follow up. Hematopoietic stem cell transplantation (HSCT) was offered for 4 patients. However due to severity of the disease and delay in diagnosis, 58% of the patients passed away in the first 2 years of life.

CONCLUSION

This study highlights the importance of early diagnosis and distribution of ITGß2 gene mutation in Egyptian children. Further molecular studies, however, remain a challenging necessity for better disease characterization in the region.

A novel mutation of the ITGB2 gene in a Chinese Zhuang minority patient with leukocyte adhesion deficiency type 1 and glucose-6-phosphate dehydrogenase deficiency

OBJECTIVES

To explore the clinical and molecular characteristics of a Chinese Zhuang minority patient with leukocyte adhesion deficiency type-1 (LAD-1) and glucose-6-phosphate dehydrogenase deficiency (G6PDD).

METHODS

Routine clinical and physical examinations were performed, and patient data was collected and analyzed. Protein expression levels of Itgb2 and glucose-6-phosphate dehydrogenase (G6pd) proteins were assessed by flow cytometry and the glucose-6-phosphate (G6P) substrate method, respectively. Whole exome sequencing was performed to investigate genetic variations of the patient and his parents.

RESULTS

The patient had fester disease and delayed separation of the umbilical cord at birth. Staphylococcus was detected in the fluid secretion of the auditory meatus of the patient. He exhibited a recurrent cheek scab, swollen hand, and swollen gum. Hematological examination indicated dramatic elevation of leukocytes including lymphocytes, monocytes, neutrophils and eosinophils. A novel homozygous mutation was detected in the ITGB2 gene of the patient, which was determined to be a two nucleotide deletion at the site of c.1537-1538 (c.1537-1538delGT), causing a frameshift of 24 amino acids from p.513 and inducing a stop codon (p.V513Lfs*24). A base substitution mutation was identified at c.1466 (c.1466G>T) of G6PD on chromosome X of the patient, which resulted in an amino acid change from arginine to leucine at p.489 (p.R489L). The patient also showed deficient lymphocyte expression of CD18 (2.99%) and significant downregulation of the G6pd protein.

CONCLUSIONS

The patient was diagnosed with G6PDD and moderate LAD-1. The combination of LAD-1 and G6PDD in this case may have been due to the high incidence of genetic disease in this minority ethnic population. Analyzing existing LAD-1 and G6PDD cases from different populations can facilitate disease diagnosis and treatment. Particularly, reporting pathogenic mutations of LAD-1 and G6PDD will be crucial for genetic testing and prenatal diagnosis in an effort to decrease the incidence of these diseases.