High prevalence of multilocus pathogenic variation in neurodevelopmental disorders in the Turkish population.

Neurodevelopmental disorders (NDDs) are clinically and genetically heterogenous; many such disorders are secondary to perturbation in brain development and/or function. The prevalence of NDDs is > 3%, resulting in significant sociocultural and economic challenges to society. With recent advances in family-based genomics, rare-variant analyses, and further exploration of the Clan Genomics hypothesis, there has been a logarithmic explosion in neurogenetic "disease-associated genes" molecular etiology and biology of NDDs; however, the majority of NDDs remain molecularly undiagnosed. We applied genome-wide screening technologies, including exome sequencing (ES) and whole-genome sequencing (WGS), to identify the molecular etiology of 234 newly enrolled subjects and 20 previously unsolved Turkish NDD families. In 176 of the 234 studied families (75.2%), a plausible and genetically parsimonious molecular etiology was identified. Out of 176 solved families, deleterious variants were identified in 218 distinct genes, further documenting the enormous genetic heterogeneity and diverse perturbations in human biology underlying NDDs. We propose 86 candidate disease-trait-associated genes for an NDD phenotype. Importantly, on the basis of objective and internally established variant prioritization criteria, we identified 51 families (51/176 = 28.9%) with multilocus pathogenic variation (MPV), mostly driven by runs of homozygosity (ROHs) - reflecting genomic segments/haplotypes that are identical-by-descent. Furthermore, with the use of additional bioinformatic tools and expansion of ES to additional family members, we established a molecular diagnosis in 5 out of 20 families (25%) who remained undiagnosed in our previously studied NDD cohort emanating from Turkey.

Contribution of genotypes in Prothrombin and Factor V Leiden to COVID-19 and disease severity in patients at high risk for hereditary thrombophilia.

Thrombotic and microangiopathic effects have been reported in COVID-19 patients. This study examined the contribution of the hereditary thrombophilia factors Prothrombin (FII) and Factor V Leiden (FVL) genotypes to the severity of COVID-19 disease and the development of thrombosis. This study investigated FII and FVL alleles in a cohort of 9508 patients (2606 male and 6902 female) with thrombophilia. It was observed that 930 of these patients had been infected by SARS-CoV-2 causing COVID-19. The demographic characteristics of the patients and their COVID-19 medical history were recorded. Detailed clinical manifestations were analyzed in a group of cases (n = 4092). This subgroup was age and gender-matched. FII and FVL frequency data of healthy populations without thrombophilia risk were obtained from Bursa Uludag University Medical Genetic Department's Exome Databank. The ratio of males (31.08%; 27.01%) and the mean age (36.85 ± 15.20; 33.89 ± 14.14) were higher among COVID-19 patients compared to non-COVID-19 patients. The prevalence of FVL and computerized tomography (CT) positivity in COVID-19 patients was statistically significant in the thrombotic subgroup (p < 0.05). FVL prevalence, CT positivity rate, history of thrombosis, and pulmonary thromboembolism complication were found to be higher in deceased COVID-19 patients (p < 0.05). Disease severity was mainly affected by FVL and not related to genotypes at the Prothrombin mutations. Overall, disease severity and development of thrombosis in COVID-19 are mainly affected by the variation within the FVL gene. Possible FVL mutation should be investigated in COVID-19 patients and appropriate treatment should be started earlier in FVL-positive patients.

Customised targeted massively parallel sequencing enables more precise diagnosis of patients with epilepsy.

BACKGROUND: Advancement in genetic technology has led to the identification of an increasing number of genes in epilepsy. This will provide a lot of information in clinical practice and improve the diagnosis and treatment of epilepsy. AIM: To show the importance of genes in the next-generation sequencing (NGS) panel during the evaluation of epilepsy and to emphasise the importance of genetic studies in different populations for the evaluation of genes that cause disease. METHODS: This was a single-centre retrospective cohort study of 80 patients who underwent NGS testing with a customised epilepsy panel. RESULTS: In a total of 54 (67.5%) out of 80 patients, pathogenic or likely pathogenic variants and variants of uncertain significance (VOUS) were identified according to the American College of Medical Genetics and Genomics criteria. Pathogenic or likely pathogenic variants (n = 35) were identified in 29 (36.25%) out of 80 individuals. VOUS (n = 34) were identified in 28 (35%) out of 80 patients. Pathogenic, likely pathogenic and VOUS were most frequently identified in TSC2 (n = 11), SCN1A (n = 6) and TSC1 (n = 5) genes. Other common genes were KCNQ2 (n = 3), AMT (n = 3), CACNA1H (n = 3), CLCN2 (n = 3), MECP2 (n = 2), ASAH1 (n = 2) and SLC2A1 (n = 2). CONCLUSIONS: NGS-based testing panels contribute to the diagnosis of epilepsy and might change the clinical management by preventing unnecessary and potentially harmful diagnostic procedures and management in patients. Thus, our results highlight the benefit of genetic testing in children suffering with epilepsy.

A Pilot Study of Identification Genetic Background of Craniosynostosis Cases.

ABSTRACT: The early fusion of the cranial sutures was described as a craniosynostosis. The early diagnosis and management of craniosynostosis is very important. Environmental factors and genetic abnormalities plays a key role during the development of craniosynostosis. Syndromic craniosynostosis cases are related with autosomal dominant disorders but nearly half of the affected cases carry a new mutation. In this study, in order to identify the genetic etiology of craniosynostosis the authors analyzed 20 craniosynostosis patients by using conventional karyotype, aCGH, sanger sequencing, next generation sequencing (NGS) and Multiplex ligation-dependent probe amplification (MLPA) techniques. The authors identified mutations on FGFR2 and FGFR3 genes which were associated with Muenke syndrome, Crouzon syndrome and skeletal dysplasia syndromes. NGS applied all of the cases and 7 clinical variations in 5 different gene were detected in %20 of cases. In addition to these abnormalities; del(11)(q14.1q22.2), del(17)(q21.31), dup(22)(q13.31) and t(2;16)(q37;p13) have been identified in our cohort which are not previously detected in craniosynostosis cases. Our study demonstrates the importance of detailed genetic analysis for the diagnosis, progression and management of the craniosynostosis.

The Phenotypic Spectrum of Desanto-Shinawi Syndrome: A Comparative Report of the First Reported Case in Turkey.

DeSanto-Shinawi syndrome (DESSH, OMIM #616708) is a rare genetic disorder caused by pathogenic variants in the WAC gene. This syndrome is characterized by a wide range of physical and neurological symptoms including dysmorphic features, developmental delay, intellectual disability, and behavioral abnormalities. DESSH was described by DeSanto in 2015, and since then, only a few dozen cases have been reported worldwide. Recent research has focused on identifying the underlying genetic cause of the syndrome as well as exploring potential treatments. In this report, we describe a female case who had dysmorphic features including long palpebral fissures, depressed nasal root, mild bulbous nasal tip, thin upper lip, hypertrichosis, short fingers, and intellectual disability, speech delay, and motor retardation. In addition, she had behavioral abnormalities such as agitation, anxiety, and attention deficit hyperactivity disorder (ADHD). Clinical exome sequencing showed a pathogenic heterozygous nonsense variant in exon 13 of the WAC gene c.1837C>T, p.(Arg613Ter) with de novo inheritance. To the best of our knowledge, this is the first case of DESSH reported from Turkey. We aimed to report this rare syndrome and compare the clinical findings of our case with previously reported cases in the literature.

Functional analysis of MMR gene VUS from potential Lynch syndrome patients.

Lynch syndrome is caused by inactivating variants in DNA mismatch repair genes, namely MLH1, MSH2, MSH6 and PMS2. We have investigated five MLH1 and one MSH2 variants that we have identified in Turkish and Tunisian colorectal cancer patients. These variants comprised two small deletions causing frameshifts resulting in premature stops which could be classified pathogenic (MLH1 p.(His727Profs*57) and MSH2 p.(Thr788Asnfs*11)), but also two missense variants (MLH1 p.(Asn338Ser) and p.(Gly181Ser)) and two small, in-frame deletion variants (p.(Val647-Leu650del) and p.(Lys678_Cys680del)). For such small coding genetic variants, it is unclear if they are inactivating or not. We here provide clinical description of the variant carriers and their families, and we performed biochemical laboratory testing on the variant proteins to test if their stability or their MMR activity are compromised. Subsequently, we compared the results to in-silico predictions on structure and conservation. We demonstrate that neither missense alteration affected function, while both deletion variants caused a dramatic instability of the MLH1 protein, resulting in MMR deficiency. These results were consistent with the structural analyses that were performed. The study shows that knowledge of protein function may provide molecular explanations of results obtained with functional biochemical testing and can thereby, in conjunction with clinical information, elevate the evidential value and facilitate clinical management in affected families.

Investigation of the Genetic Etiology in Idiopathic Generalized Epileptic Disorders by Targeted Next-generation Sequencing Technique

Background: Idiopathic generalized epilepsy is the most common group of epilepsy disorders in children and adolescents. Various types of genetic abnormality were identified among the hereditary factors that explain epilepsy. Aims: To determine the variations in the etiopathogenesis, treatment protocol planning, and prognosis of idiopathic generalized epilepsy using the next-generation sequencing method. Study Design: A cross-sectional study. Methods: This study included 32 patients with idiopathic generalized epilepsy. Genomic DNA was obtained from peripheral venous blood samples taken from the patients. A total of 18 genes encoding ion channel subunits that are involved in monogenic disorders and are associated with idiopathic generalized epilepsy were included. The targeted custom next-generation sequencing panel was designed to cover all coding exons and all exon/intron splice site regions of 18 genes. Results: We detected 9 (28%) variations, including 1 likely pathogenic (a variant in the SCN1A gene) and 8 of unknown clinical significance (2 in the CLCN2 genes, GABBR2, SCN1B, SLC2A1, SLC4A10 genes, and 2 in the TBC1D24 gene). Conclusion: Study results should be supported by functional advanced studies, with increased existing knowledge in the relevant variations.

The Frequency of SMN1, SMN2 Copy Numbers in 246 Turkish Cases Analyzed with MLPA Method.

This study aimed to define the copy numbers of SMN1 and SMN2 genes and the diagnosis rate and carrier frequency of spinal muscular atrophy (SMA) in the Thrace region of Turkey. In this study, the frequency of deletions in exons 7 and 8 in the SMN1 gene and SMN2 copy numbers were investigated. A total of 133 cases with the preliminary diagnosis of SMA and 113 cases with the suspicion of being an SMA carrier from independent families were analyzed by multiplex ligation-dependent probe amplification method for SMN1 and SMN2 gene copy numbers. SMN1 homozygous deletions were detected in 34 patients (25.5%) of 133 cases with the suspicion of SMA. Cases diagnosed with SMA type I was 41.17% (14/34), 29.4% (10/34) with type II, 26.4% (9/34) with type III, and 2.94% (1/34) with type IV. The SMA carrier rate was 46.01% in 113 cases. In 34 SMA cases, SMN2 copy numbers were: two copies - 28 cases (82.3%), three copies - 6 cases (17.6%). SMN2 homozygous deletions were detected in 15% (17/113) of carrier analysis cases. The consanguinity rate of the parents was 23.5% in SMA diagnosed cases. In this study, we had a 25.5% of SMA diagnosis rate and 46% SMA carrier frequency. The current study also showed the relatively low consanguinity rate of the Thrace region, with 23.5% according to the east of Turkey.

Diagnostic Value of Microarray Method in Autism Spectrum Disorder, Intellectual Disability, and Multiple Congenital Anomalies and Some Candidate Genes for Autism: Experience of Two Centers.

Objective: This study aimed to demonstrate the diagnostic value of microarray testing in autism spectrum disorder, intellectual disability, and multiple congenital anomalies of unknown etiology, as well as to report some potential candidate genes for autism. Methods: Microarray analysis records between January 2016 and December 2017 from two Genetic Diagnostic Centers in Turkey, Kanuni Sultan Suleyman and Adana Numune Training and Research Hospital, were compiled. Detected copy number variations (CNVs) were classified as benign, likely benign, variants of uncertain significance (VUS), likely pathogenic, and pathogenic according to American College of Medical Genetics and Genomics guidelines. The clinical findings of the some patients and the literature data were compared. Results: In 109 (24.5%) of 445 patients, a total of 163 CNVs with reporting criterion feature were detected. Sixty-nine (42%) and 8 (5%) of these were evaluated as pathogenic and likely pathogenic, respectively. Fifteen (9%) CNVs were also evaluated as VUS. Pathogenic or likely pathogenic CNVs were detected in 61 (13.6%) of 445 patients. Conclusions: We found that the probability of elucidating the etiology of microarray method in autism spectrum disorder, intellectual disability, and multiple congenital anomalies is 13.6% with a percentage similar to the literature. We suggest that the MYT1L, PXDN, TPO, and AUTS2 genes are all strong candidate genes for autism spectrum disorders. We detailed the clinical findings of the cases and reported that some CNV regions in the genome may be associated with autism.

Clinical Implications of Chromosome 16 Copy Number Variation.

Chromosome 16 is one of the gene-rich chromosomes; however, approximately 10% of the chromosome 16 sequence is composed of segmental copies, which renders this chromosome instable and predisposes it to rearrangements via frequent nonallelic homologous recombination. Microarray technologies have enabled the analysis of copy number variations (CNV), which may be associated with the risk of developing complex diseases. Through comparative genomic hybridisation in 1,298 patients, we detected 18 cases with chromosome 16 CNV. We identified 2recurrent CNV regions, including 1 at 16p13.11 in 4 patients and another at 16p11.2 in 7 patients. We also detected atypical chromosome 16 rearrangements in 7 patients. Furthermore, we noted an increased frequency of co-occurring genomic changes, supporting the two-hit hypothesis to explain the phenotypic variability in the clinical presentation of CNV syndromes. Our findings can contribute to the creation of a chromosome 16 disease map based on regions that may be associated with disease development.

Investigating the Genetic Etiology of Pediatric Patients with Peripheral Hypotonia Using the Next-Generation Sequencing Method.

Background Hypotonia occurs as a result of neurological dysfunction in the brain, brainstem, spinal cord, motor neurons, anterior horn cells, peripheral nerves, and muscles. Although the genotype-phenotype correlation can be established in 15 to 30% of patients, it is difficult to obtain a correlation in most cases. Aims This study was aimed to investigate the genetic etiology in cases of peripheral hypotonia that could not be diagnosed using conventional methods. Methods A total of 18 pediatric patients with peripheral hypotonia were included. They were referred to our genetic disorders diagnosis center from the Pediatric Neurology Department with a prediagnosis of hypotonia. A custom designed multigene panel, including ACTA1 , CCDC78 , DYNC1H1 , GARS , RYR1 , COL6A1 , COL6A2 , COL6A3 , FKRP , FKTN , IGHMBP2 , LMNA , LAMA2 , LARGE1 , MTM1 , NEM , POMGnT1 , POMT1 , POMT2 , and SEPN1 , was used for genetic analysis using next-generation sequencing (NGS). Results In our study, we found 13 variants including pathogenic (two variants in LAMA2) and likely pathogenic variants (three variants in RYR1 and POMGnT1) and variants of uncertain clinical significance (eight variants in RYR1, COL6A3, COL6A2, POMGnT1 and POMT1) in 11 (61%) out of 18 patients. In one of our patients, a homozygous, likely pathogenic c.1649G > A, p.(Ser550Asn) variant was defined in the POMGnT1 gene which was associated with a muscle-eye-brain disease phenotype. Conclusion The contribution of an in-house designed gene panel in the etiology of peripheral hypotonia with a clinical diagnosis was 5.5%. An important contribution with the clinical diagnosis can be made using the targeted multigene panels in larger samples.

Prenatal diagnosis and molecular cytogenetic characterization of partial dup (18p)/del (18q) due to a maternal pericentric inversion 18 in a foetus with multiple anomalies.

OBJECTIVE: The 18q terminal deletion with inverted duplication is an extremely rare abnormality, with only three confirmed cases in Europe to date. Here, we report, for the first time, a case of de novo 18q inv-dup-del in a Turkish pregnant woman. CASE REPORT: A 30-year-old pregnant woman was referred for genetic analysis at her 25th gestational week due to foetal diaphragmatic hernia and rocker bottom feet. Cytogenetic analysis of the parents revealed a karyotype of 46,XX,inv(18) (p11.3q21.3) of the mother and a normal karyotype of the father. The foetal karyotype was defined as 46,XX,rec(18)del(18q)inv(18) (p11.3q21.3)mat. CONCLUSION: To our knowledge, this is the first report of a prenatal diagnosis. Genetic counselling issues for this family, particularly affected individuals, include an increased likelihood of reduced fertility and a risk of recurrence of parental inversion equal to 1/2 in surviving offspring.

First Report of Jacobsen Syndrome with Dextrocardia Diagnosed with del(11)(q24q25).

Jacobsen syndrome is a rare congenital disorder that is caused by the deletion of several genes in chromosome 11. A 10-year-old female with congenital heart disease, dextrocardia, and coarse facial appearance was examined in our medical genetics clinic. Chromosome analysis and array-CGH showed a copy number loss of 9 Mb in the 11q24.2q25 region. Herein, we report her clinical findings. This is the first case of Jacobsen syndrome with dextrocardia.

Investigation of Genetic Alterations in Congenital Heart Diseases in Prenatal Period.

The prenatal diagnosis of congenital heart disease (CHD) is important because of mortality risk. The onset of CHD varies, and depending on the malformation type, the risk of aneuploidy is changed. To identify possible genetic alterations in CHD, G-banding, chromosomal microarray or if needed DNA mutation analysis and direct sequence analysis should be planned. In present study, to identify genetic alterations, cell culture, karyotype analysis, and single nucleotide polymorphism, array analyses were conducted on a total 950 samples. Interventional prenatal genetic examination was performed on 23 (2, 4%, 23/950) fetal CHD cases. Chromosomal abnormalities were detected in 5 out of 23 cases (21, 7%). Detected chromosomal abnormalities were 10q23.2 deletion, trisomy 18, 8p22.3-p23.2 deletion, 8q21.3-q24.3 duplication, 11q24.2q24.5 (9 Mb) deletion, and 8p22p12 (16.8 Mb) deletion. Our study highlights the importance of genetic testing in CHD.

Clinical Features of Aberrations Chromosome 22q: A Pilot Study.

Objective A significant number of genetic variations have been identified in chromosome 22, using molecular genetic techniques. Various genomic disorders on chromosome 22, including cat's eye syndrome caused by extra copies of the proximal region of the 22q chromosome, are now well-defined. Our aim in the study was to show phenotypic variability associated with rearrangements of the 22q chromosomal region. Methods We focused our study on clinical aspects of these disorders, including genetic testing, genotype-phenotype correlation, and potential treatments. A total of 998 patients were referred for genetic analysis (Karyotyping, MLPA, array-CGH) during January 2015 to February 2020 because of intellectual deficiency, behavior issues, and/or multiple congenital abnormalities in several genetics departments. Informed consent was obtained from all the patients and/or their parents. Results 22q11.21 or 22q13.33 microdeletions and 22q11.22-q11.23 microduplication were identified in 31 patients out of referrals. The 22q aberrations were detected in 31/998 patients, giving a prevalence of 3.1%. In this study, 18 patients with 22q11.2 (LCR22A-H) deletion, three patients with 22q13.31 deletion, 9 patients with 22q11.2 duplication and one patient with 22q13.31 duplication were identified. We report on the clinical and molecular characterization of 31 individuals with distal deletions and duplications of chromosome 22q. Conclusions The current study demonstrated in the largest postnatal case series reporting the whole spectrum of atypical phenotypic and genotypic variations at 22q. We believe that when all the phenotypic differences are taken into account, various anomalies including developmental delay and intellectual disability might be considered as an indication to search for aberrations of 22q along with congenital heart diseases.

Investigation on the Effects of Modifying Genes on the Spinal Muscular Atrophy Phenotype.

Introduction Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by the degeneration of motor neurons, muscle weakness, and atrophy that leads to infant's death. The duplication of exon 7/8 in the SMN2 gene reduces the clinical severity of disease, and it is defined as modifying effect. In this study, we aim to investigate the expression of modifying genes related to the prognosis of SMA like PLS3 , PFN2 , ZPR1 , CORO1C , GTF2H2 , NRN1 , SERF1A , NCALD , NAIP , and TIA1. Methods Seventeen patients, who came to Trakya University, Faculty of Medicine, Medical Genetics Department, with a preliminary diagnosis of SMA disease, and eight healthy controls were included in this study after multiplex ligation-dependent probe amplification analysis. Gene expression levels were determined by real-time reverse transcription polymerase chain reaction and delta-delta CT method by the isolation of RNA from peripheral blood of patients and controls. Results SERF1A and NAIP genes compared between A group and B + C + D groups, and A group of healthy controls, showed statistically significant differences ( p = 0.037, p = 0.001). Discussion PLS3, NAIP , and NRN1 gene expressions related to SMA disease have been reported before in the literature. In our study, the expression levels of SERF1A , GTF2H2 , NCALD , ZPR1 , TIA1 , PFN2 , and CORO1C genes have been studied for the first time in SMA patients.

Comprehensive Genetic Analysis of RASopathy in the Era of Next-Generation Sequencing and Definition of a Novel Likely Pathogenic >KRAS Variation.

Introduction: Germline pathogenic variations of the genes encoding the components of the Ras-MAPK pathway are found to be responsible for RASopathies, a clinically and genetically heterogeneous group of diseases. In this study, we aimed to present the results of patients genetically investigated for RASopathy-related mutations in our Genetic Diagnosis Center. Methods: The results of 51 unrelated probands with RASopathy and 4 affected relatives (31 male, 24 female; mean age: 9.327 ± 8.214) were included in this study. Mutation screening was performed on DNA samples from peripheral blood of the patients either by Sanger sequencing of PTPN11 hotspot regions (10/51 probands), or by a targeted amplicon next-generation sequencing panel (41/51 probands) covering the exonic regions of BRAF, CBL, HRAS, KRAS, LZTR1, MAP2K1, MAP2K2, NF1, NRAS, PTPN11, RAF1, RASA2, RIT1, SHOC2, SOS1, SOS2, SPRED1, and KAT6B genes. Results: Pathogenic/likely pathogenic variations found in 22 out of 51 probands (43.13%) and their 4 affected family members were located in PTPN11, BRAF, KRAS, NF1, RAF1, SOS1, and SHOC2 genes. The c.148A>C (p.Thr50Pro) variation in the KRAS gene was a novel variant detected in a sibling in our patient cohort. We found supportive evidence for the pathogenicity of the NF1 gene c.5606G>T (p.Gly1869Val) variation which we defined in an affected boy who inherited the mutation from his affected father. Conclusion: Although PTPN11 is the most frequently mutated gene in our patient cohort, as in most previous reports, different mutation distribution among the other genes studied motivates the use of a next-generation sequencing gene panel including the possible responsible genes.

Novel c.1505_1509dupCTGCC pathogenic variation in a male case with Christianson syndrome.

Pathogenic variations in the SLC9A6 gene are associated with an X-linked disorder Christianson syndrome characterized by developmental delay, microcephaly, intellectual disability, autistic-like behavior and epilepsy. We identified a novel pathogenic variation in the SLC9A6 gene in a boy with developmental delay and microcephaly. Herein we report the clinical findings of the case diagnosed as Christianson syndrome; his mother was found to carry the same variant.

Wiedemann-Steiner Syndrome as a Differential Diagnosis of Cornelia de Lange Syndrome Using Targeted Next-Generation Sequencing: A Case Report.

Wiedemann-Steiner syndrome (WDSTS) is a rare autosomal dominant disorder with a variable clinical phenotype including synophrys, hypertelorism, thick eyebrows, long eyelashes, wide nasal bridge, long philtrum, hypertrichosis, growth retardation, and intellectual disability. Cornelia de Lange syndrome (CdLS) is a rare disease characterized by synophrys, long eyelashes, limb abnormalities, generalized hirsutism, growth retardation, and intellectual disability. In both WDSTS and CdLS, the malformations are due to transcriptome disturbance caused by defects in the genes encoding the components of chromatin regulation and transcription process. The overlapping features in these two syndromes may complicate the original diagnosis of a patient. Here, we report on a Wiedemann-Steiner patient found to have a de novo pathogenic KMT2A variation who had been clinically suspected as CdLS. We suggest that targeted next-generation sequencing is a feasible tool for the precise diagnosis of patients who have phenotypically and clinically overlapping features of CdLS and WDSTS.

Targeted massively parallel sequencing in the management of cytogenetically normal lymphoid malignancies.

The variations in clinical and biological background of lymphoid malignancies trigger researchers to try to find out novel therapeutic targets. A typical treatment includes multiagent chemotherapy and/or targeted therapy in the light of driver mutations. Next generation sequencing (NGS) plays a pivotal role during the identification of genetic alterations in lymphoid malignancies. A total of 52 patients [30 men (58%) and 22 women (42%)] having normal cytogenetic and FISH results were enrolled in this study. Usage of NGS based targeted sequencing could confirm or support a particularly preferred diagnosis (41/52, 78%) or make a differential diagnosis in cases of interference. Notably, in 11 out of these 52 cases (21%), the initial suspect diagnosis was not supported by the NGS result and thereby had to be reconsidered. In this study, we highlight the importance of targeted NGS panel testing for diagnosis, prognosis and treatment decision in highly selected instances of lymphoid malignancies and lymphoproliferative disorders in which histopathology and more conventional molecular analyses remain inconclusive.