Lipoid proteinosis: Novel ECM1 pathogenic variants and intrafamilial variability in four unrelated Arab families

BACKGROUND/OBJECTIVES

Lipoid proteinosis (LP) is a rare autosomal recessive multisystem disorder that is caused by loss-of-function pathogenic variants in the extracellular matrix protein-1 (ECM1) gene. The typical clinical manifestations of LP include hoarseness of voice, beaded papules on the eyelids, infiltration and scarring of the skin and mucosa, as well as neuropsychological abnormalities. Currently, more than 70 pathogenic variants have been reported, including nonsense, missense, splice site, deletion and insertion pathogenic variants, and more than half of them occurred in exons 6 and 7.

METHODS

Clinical evaluation and Sanger sequencing were performed on eight patients from four unrelated Arab families.

RESULTS

We identified two novel ECM1 variants, one nonsense pathogenic variant in exon 6 (c.579G>A, p.Trp193*) and a deletion of three nucleotides (c.1390_1392del, p.Glu464del) in exon 9, and two previously reported frameshift variants; c.692_693delAG, in exon 6 and c.11dupC in exon 1.

CONCLUSIONS

Although all patients had characteristic manifestations of lipoid proteinosis, we observed intrafamilial phenotypic variability. Our data expand the pathogenic variant spectrum of ECM1 and also supports the fact that exon 6 is one of the most common hot spots of pathological variants in ECM1.

Physicians' knowledge and practice concerning diagnosis and management of anaphylaxis: The situation in Egypt

Introduction

Early recognition of an anaphylaxis event is crucial for instituting lifesaving management. We sought to explore knowledge and practice towards anaphylaxis in a sample of physicians from ten Egyptian governorates.

Methods

An eighteen question-based questionnaire was developed by expert allergists to evaluate the knowledge and practice towards anaphylaxis, based on the World Allergy Organization guidelines for the assessment and management of anaphylaxis. The questionnaires were distributed, and the answered forms collected via emails, and data were tabulated, and analysed.

Results

In this cross-sectional study, a total of 242 physicians completed the survey (183 (75.6%) paediatricians, 32 (13.2%) internists, 22 (9.1%) intensivists and five (2.1%) anaesthetists). Only 91 participants (37.6%) identified all the four proposed anaphylaxis clinical scenarios while 70, 45 and 36 identified three, two and one scenario, respectively. Loss of consciousness and abdominal symptoms were not recognised as possible presentations of anaphylaxis by 64.5% and 80.2% of the participants, respectively. Epinephrine was considered the first line treatment by 98 (40.5%), corticosteroids by 77 (31.8%) and antihistamines by 25 (10.3%). 75 (31%) responders identified the right dose of epinephrine while 119 (49.2%) identified the proper route. Concerning practice, 83 physicians (39.2%) used epinephrine for all cases of anaphylaxis, 88 (41.5%) used it for refractory cases only whereas 41 (19.3%) did not use epinephrine at all.

Discussion

Our survey shows that the knowledge of Egyptian physicians and their practice towards anaphylaxis are still inadequate. The current situation reinforces the need to disseminate and encourage the adoption of the international guidelines for anaphylaxis diagnosis and treatment.

Clinical Phenotypes and Immunological Characteristics of 18 Egyptian LRBA Deficiency Patients

LPS-responsive beige-like anchor (LRBA) deficiency is an autosomal recessive primary immunodeficiency disorder, OMIM (#614700). LRBA deficiency patients suffer from variable manifestations including recurrent infections, immune dysregulation, autoimmunity, cytopenias, and enteropathy. This study describes different clinical phenotypes and immunological characteristics of 18 LRBA deficiency patients diagnosed from Egypt. T and B lymphocyte subpopulations, LRBA, and cytotoxic T lymphocyte-associated protein 4 (CTLA4) expression were evaluated in resting and stimulated T cells using flow cytometry. Next-generation sequencing was used to identify mutations in the LRBA gene. LRBA deficiency patients had significantly lower B cells and increased percentage of memory T cells. CTLA4 levels were lower in LRBA-deficient T regulatory cells in comparison to healthy donors at resting conditions and significantly increased upon stimulation of T cells. We identified 11 novel mutations in LRBA gene ranging from large deletions to point mutations. Finally, we were able to differentiate LRBA-deficient patients from healthy control and common variable immunodeficiency patients using a simple flow cytometry test performed on whole blood and without need to prior stimulation. LRBA deficiency has heterogeneous phenotypes with poor phenotype-genotype correlation since the same mutation may manifest differently even within the same family. Low LRBA expression, low numbers of B cells, increased numbers of memory T cells, and defective CTLA4 expression (which increase to normal level upon T cell stimulation) are useful laboratory tests to establish the diagnosis of LRBA deficiency. Screening of the siblings of affected patients is very important as patients may be asymptomatic at the beginning of the disease course.

Clinical utility of NGS diagnosis and disease stratification in a multiethnic primary ciliary dyskinesia cohort

BACKGROUND

Primary ciliary dyskinesia (PCD), a genetically heterogeneous condition enriched in some consanguineous populations, results from recessive mutations affecting cilia biogenesis and motility. Currently, diagnosis requires multiple expert tests.

METHODS

The diagnostic utility of multigene panel next-generation sequencing (NGS) was evaluated in 161 unrelated families from multiple population ancestries.

RESULTS

Most (82%) families had affected individuals with biallelic or hemizygous (75%) or single (7%) pathogenic causal alleles in known PCD genes. Loss-of-function alleles dominate (73% frameshift, stop-gain, splice site), most (58%) being homozygous, even in non-consanguineous families. Although 57% (88) of the total 155 diagnostic disease variants were novel, recurrent mutations and mutated genes were detected. These differed markedly between white European (52% of families carry DNAH5 or DNAH11 mutations), Arab (42% of families carry CCDC39 or CCDC40 mutations) and South Asian (single LRRC6 or CCDC103 mutations carried in 36% of families) patients, revealing a striking genetic stratification according to population of origin in PCD. Genetics facilitated successful diagnosis of 81% of families with normal or inconclusive ultrastructure and 67% missing prior ultrastructure results.

CONCLUSIONS

This study shows the added value of high-throughput targeted NGS in expediting PCD diagnosis. Therefore, there is potential significant patient benefit in wider and/or earlier implementation of genetic screening.