ABCA3 Gene Defect - Cause of Severe Respiratory Distress and Failure in Newborn

Surfactant metabolism disorders are rare cause of RDS in term neonates. A near term male neonate presented with respiratory distress syndrome (required Surfactant multiple times) with family history of one still birth and one neonatal death due to RDS in previous siblings. A homozygous missense variation in exon 7 of the ABCA3 gene that results in the amino acid substitution of leucine for proline at codon 186 was detected. He died of severe respiratory failure even after multiple doses of surfactant and ventilation. Surfactant deficiency with ABCA3 gene mutation needs to be suspected in term neonate who present with respiratory distress syndrome with family history or neonatal death with respiratory distress. Keywords: ABCA3 gene defect, Respiratory distress syndrome (RDS), neonates, neonatal death.

Mutated CCDC51 Coding for a Mitochondrial Protein, MITOK Is a Candidate Gene Defect for Autosomal Recessive Rod-Cone Dystrophy

The purpose of this work was to identify the gene defect underlying a relatively mild rod-cone dystrophy (RCD), lacking disease-causing variants in known genes implicated in inherited retinal disorders (IRD), and provide transcriptomic and immunolocalization data to highlight the best candidate. The DNA of the female patient originating from a consanguineous family revealed no large duplication or deletion, but several large homozygous regions. In one of these, a homozygous frameshift variant, c.244_246delins17 p.(Trp82Valfs*4); predicted to lead to a nonfunctional protein, was identified in CCDC51. CCDC51 encodes the mitochondrial coiled-coil domain containing 51 protein, also called MITOK. MITOK ablation causes mitochondrial dysfunction. Here we show for the first time that CCDC51/MITOK localizes in the retina and more specifically in the inner segments of the photoreceptors, well known to contain mitochondria. Mitochondrial proteins have previously been implicated in IRD, although usually in association with syndromic disease, unlike our present case. Together, our findings add another ultra-rare mutation implicated in non-syndromic IRD, whose pathogenic mechanism in the retina needs to be further elucidated.

Prediction of Treatment Efficacy in Relapsed Chronic Lymphocytic Leukemia

Background. The emergence of signaling pathway inhibitors (SPI) considerably improved the prognosis in relapsed chronic lymphocytic leukemia (R-CLL). Nevertheless, some patients cannot achieve optimal and sustained response. TP53 gene defects determine the refractoriness to immunochemotherapy (ICT) and lower rates of progression-free survival on SPI therapy. However, the prognostic value of complex karyotype (CK) in CLL has long been disputed. In recent years, greater attention has been placed on the prognostic impact of CK in the context of SPI therapy. Materials & Methods. The study included 180 patients who received the drug treatment for R-CLL (113 of them with ICT, 67 of them with SPI). Their age at the onset of second-line therapy, the response to first-line therapy, early (< 24 months) progression after first-line therapy, the number of therapy lines, and the presence of CK and TP53 gene defect were regarded as prognostic markers. Taking into account the clonal evolution in CLL, to assess the significance degree of the above predictors, Cox proportional hazards regression model with time-dependent variables was used. Results. The following independent factors proved to significantly reduce the risk of death: response achieved immediately after first-line therapy (hazard ratio [HR] 0.38; 95% confidence interval [95% CI] 0.20-0.72; p = 0.003) and the number of therapy lines (HR 0.56; 95% CI 0.37-0.86; p = 0.008). Treatment with only ICT in first and subsequent lines was associated with increasing risk of death (HR 2.25; 95% CI 1.09-4.63; p = 0.028). Genetic risks worsened the prognosis to a high degree of significance in the case of TP53 gene defect with excluded or unknown CK status (HR 10.54; 95% CI 4.25-26.17; p < 0.001) as well as in the case of CK (HR 14.08; 95% CI 5.77-34.35; p < 0.001). A significant predictor of poor outcome was reported to be the factor of unknown CK status without TP53 gene defect (HR 4.15; 95% CI 1.72-10.00; p = 0.002). Neither relapse time after first-line therapy nor the age > 65 years showed independent prognostic value. Conclusion. Standard karyotyping of peripheral lymphocytes with specific stimulation establishes a clearer disease prognosis and suggests the optimal choice of R-CLL treatment strategy.

Marginal acrokeratoderma: a case series

<p>Marginal acrokeratoderma (MAK) are complex disorders characterized by distribution of cornified papules/plaques along the dorso-plantar and dorso-palmar junction of the feet and hands. They belong to the family of punctate palmoplantar keratoderma. No associated gene defect has been detected. There are two clinically identical types of hereditary/familial MAK; namely acrokeratoelastoidosis (AKE) and focal acral hyperkeratosis (FAH); differentiated by the presence of elastorrehexis in AKE. The aim of this article is to report MPK lesions that are not included in the familiar groupings of punctate and polygonal papules. We described thirteen cases and reviewed the literature. Average age at presentation was 24 years, age ranged from 5 to 79 years. Majority of our cases had lesions on only their feet, that of FAH had lesions on only their hands and AKE had lesions on both hands and feet. Although most lesions reported in literature with FAH and AKE were characterized as 2-5mm flesh-colored to yellowish flat-topped/polygonal, keratotic/punctate papules, coalescing into plaques, we also reported lesions that were keratotic with cracks, desquamating and cobble-stone in appearance. This case series calls for more studies on variations in clinical presentation of MAK lesions and an opportunity to revisit the genetic basis and investigate triggers of this rare disorder.</p>

Spectrum of Genetic Defects and Phenotype-Genotype Correlation in Dyserythropoietic Anemias: Bench to Bedside Approach in the Indian Scenario

Introduction Congenital dyserythropoietic anemias (CDA) are rare inherited red cell disorders characterized by ineffective erythropoiesis and inappropriate reticulocytopenia. CDAs are usually difficult to diagnose due to variable phenotypes and overlapping bone marrow (BM) morphology with other disorders. Numerous implicated causal genes make Sanger sequencing a less likely approach and hence, the use of targeted resequencing can expedite molecular diagnosis. This study aimed at determining the genetic spectrum of CDAs and translating the results into patient care. Methods Twenty nine patients with clinical and laboratory evidence suggestive of CDA and 1 patient suggestive of CDA with thrombocytopenia by BM morphology were studied. Various biochemical and molecular tests were done to exclude common hemolytic anemias. Common SEC23B: p.Tyr462Cys variant in our patients with CDA was screened by Sanger sequencing. DNA libraries were prepared using TruSight One Sequencing Panel and TruSeq Custom Amplicon Panel and sequenced on Illumina platform. After data analysis variants were classified and the most likely disease-causing variants were validated by Sanger sequencing followed by pedigree analysis. Results Out of 27 patients of suspected CDA, SEC23B: p.Tyr462Cys variant was found in 10 patients. Rest of the remaining 17 patients were subjected to targeted resequencing. Data analysis revealed novel potentially pathogenic variants in compound heterozygosity in SEC23B in 4 patients and 1 patient had a heterozygous variant in SEC23B. There could be the possibility of intronic or large indel in her. The variants were distributed throughout the SEC23B gene. Notably, in 7 patients with suspected CDA, the final molecular diagnosis were hemolytic anemias. Of them, 4 showed likely pathogenic variants in PKLR gene and 1 each had probably causal variant in MTRR, SPTB and PIEZO1 genes. In the patient's with pyruvate kinase deficiency, screening by enzyme assays were normal. Except for the patient with MTRR gene defect all 6 had transfusion dependent anemia and BM showed dyserythropoiesis. One patient each of GATA1 gene variant (novel) and a known pathogenic variant p.Glu325Lys in KLF1 gene (CDA type IV) was detected. Of 17 cases subjected to targeted resequencing the diagnosis was achieved in ~76% (13/17) of cases. The phenotypes correlated with the genetic defects found in the SEC23B gene. The homozygous and compound heterozygous defects in this gene cause CDA type II. As anticipated GATA1 gene defect (p.Val205Leu) was found in a patient of X-linked thrombocytopenia with dyserythropoietic anemia. Patient with KLF1 had high levels of fetal hemoglobin along with features of dyserythropoiesis in BM compatible with the phenotype of variant p.Glu325Lys causing CDA type IV. Phenotype-genotype correlation was discrepant in 7 cases of CDA. In 4 cases pyruvate kinase deficiency (PKLR) was found and each case of hereditary xerocytosis (PIEZO1), membrane defect (SPTB) and MTRR defect was found. Conclusion(s) CDA showed a highly varied etiology. Our experience demonstrates a high diagnostic yield (~76%) of targeted resequencing for molecular diagnosis of suspected CDAs. Discrepancy was noted in 41% (7/17) cases with suspected CDA which were diagnosed as hemolytic anemia after molecular analysis. Establishing the correct diagnosis of pyruvate kinase deficiency led to an evidence-based decision of splenectomy that eliminated transfusion dependence. In the patient with MTRR defect change in therapy was suggested. Prenatal diagnosis was done for 2 families, where in 1 of the family both the SEC23B variants were novel and in compound heterozygosity. This study highlights the importance of genetic testing in patients under frequent blood transfusions and suspected CDAs, to provide accurate diagnosis and therapeutic interventions. Disclosures No relevant conflicts of interest to declare.