Amyotrophic lateral sclerosis (ALS) is a presently incurable neurodegenerative disease. Some genes have a causal relationship to ALS, others act as susceptibility and/or risk factors. We aimed to elucidate the role of 14 ALS-related genes in the Hungarian ALS population of 183 patients. Mutation screening of major ALS genes was performed. SMN1 and SMN2 genes were examined by multiplex ligation-dependent probe-amplification assay; intermediate repeat expansions in the ATXN1 and ATXN2 genes were analyzed by fragment analysis. Additional variants in putative ALS genes were screened from previously acquired next generation sequencing data. We confirmed the repeat expansion of the C9orf72, ATXN1 and ATXN2 genes as ALS risk factors in this Hungarian cohort. Additionally, we identified a pathogenic SOD1 mutation and suggested its founder effect. A likely pathogenic variant in the MFSD8 gene was detected, and variants of interest were uncovered in the ANXA11 and GLT8D1 genes. We provide valuable data as part of the growing body of work on population-specific aspects of the genetic background of ALS.

Fibrillin-1 and fibrillin-2, encoded by FBN1 and FBN2, respectively, play significant roles in elastic fiber assembly, with pathogenic variants causing a diverse group of connective tissue disorders such as Marfan syndrome (MFS) and congenital contractural arachnodactyly (CCD). Different genomic variations may lead to heterogeneous phenotypic features and functional consequences. Recent high-throughput sequencing modalities have allowed detection of novel variants that may guide the care for patients and inform the genetic counseling for their families. We performed clinical phenotyping for two newborn infants with complex congenital heart defects. For genetic investigations, we employed next-generation sequencing strategies including whole-genome Single-Nucleotide Polymorphism (SNP) microarray for infant A with valvular insufficiency, aortic sinus dilatation, hydronephrosis, and dysmorphic features, and Trio whole-exome sequencing (WES) for infant B with dextro-transposition of the great arteries (D-TGA) and both parents. Infant A is a term male with neonatal marfanoid features, left-sided hydronephrosis, and complex congenital heart defects including tricuspid regurgitation, aortic sinus dilatation, patent foramen ovale, patent ductus arteriosus, mitral regurgitation, tricuspid regurgitation, aortic regurgitation, and pulmonary sinus dilatation. He developed severe persistent pulmonary hypertension and worsening acute hypercapnic hypoxemic respiratory failure, and subsequently expired on day of life (DOL) 10 after compassionate extubation. Cytogenomic whole-genome SNP microarray analysis revealed a deletion within the FBN1 gene spanning exons 7–30, which overlapped with the exon deletion hotspot region associated with neonatal Marfan syndrome. Infant B is a term male prenatally diagnosed with isolated D-TGA. He required balloon atrial septostomy on DOL 0 and subsequent atrial switch operation, atrial septal defect repair, and patent ductus arteriosus ligation on DOL 5. Trio-WES revealed compound heterozygous c.518C>T and c.8230T>G variants in the FBN2 gene. Zygosity analysis confirmed each of the variants was inherited from one of the parents who were healthy heterozygous carriers. Since his cardiac repair at birth, he has been growing and developing well without any further hospitalization. Our study highlights novel FBN1/FBN2 variants and signifies the phenotype–genotype association in two infants affected with complex congenital heart defects with and without dysmorphic features. These findings speak to the importance of next-generation high-throughput genomics for novel variant detection and the phenotypic variability associated with FBN1/FBN2 variants, particularly in the neonatal period, which may significantly impact clinical care and family counseling.

Congenital heart defects (CHD) are the most common developmental abnormalities, affecting approximately 0.9% of livebirths. Genetic factors, including copy number variations (CNVs), play an important role in their development. The most common CNVs are found on chromosome 22q11.2. The genomic instability of this region, caused by the eight low copy repeats (LCR A-H), may result in several recurrent and/or rare microdeletions and duplications, including the most common, ∼3 Mb large LCR A-D deletion (classical 22q.11.2 deletion syndrome). We aimed to screen 22q11.2 CNVs in a large Hungarian pediatric and adult CHD cohort, regardless of the type of their CHDs. All the enrolled participants were cardiologically diagnosed with non-syndromic CHDs. A combination of multiplex ligation-dependent probe amplification (MLPA), chromosomal microarray analysis and droplet digital PCR methods were used to comprehensively assess the detected 22q11.2 CNVs in 212 CHD-patients. Additionally, capillary sequencing was performed to detect variants in the TBX1 gene, a cardinal gene located in 22q11.2. Pathogenic CNVs were detected in 5.2% (11/212), VUS in 0.9% and benign CNVs in 1.8% of the overall CHD cohort. In patients with tetralogy of Fallot the rate of pathogenic CNVs was 17% (5/30). Fifty-four percent of all CNVs were typical proximal deletions (LCR A-D). However, nested (LCR A-B) and central deletions (LCR C-D), proximal (LCR A-D) and distal duplications (LCR D-E, LCR D-H, LCR E-H, LCR F-H) and rare combinations of deletions and duplications were also identified. Segregation analysis detected familial occurrence in 18% (2/11) of the pathogenic variants. Based on in-depth clinical information, a detailed phenotype–genotype comparison was performed. No pathogenic variant was identified in the TBX1 gene. Our findings confirmed the previously described large phenotypic diversity in the 22q11.2 CNVs. MLPA proved to be a highly efficient genetic screening method for our CHD-cohort. Our results highlight the necessity for large-scale genetic screening of CHD-patients and the importance of early genetic diagnosis in their clinical management.

One out of every hundred live births present with congenital heart abnormalities caused by the aberrant development of the embryonic cardiovascular system. The conserved zinc finger transcription factor proteins, which include GATA binding protein 5 (GATA5) and GATA binding protein (GATA6) play important roles in embryonic development and their inactivation may result in congenital heart defects (CHDs). In this study, we performed genotypic–phenotypic analyses in two families affected by right-sided CHD diagnosed by echocardiography imaging. Proband A presented with pulmonary valve stenosis, and proband B presented with complex CHD involving the right heart structures. For variant detection, we employed whole-genome single-nucleotide polymorphism (SNP) microarray and family-based whole-exome sequencing (WES) studies. Proband A is a full-term infant who was admitted to the neonatal intensive care unit (NICU) at five days of life for pulmonary valve stenosis (PVS). Genomic studies revealed a normal SNP microarray; however, quad WES analysis identified a novel heterozygous [Chr20:g.61041597C>G (p.Arg237Pro)] variant in the GATA5 gene. Further analysis confirmed that the novel variant was inherited from the mother but was absent in the father and the maternal uncle with a history of heart murmur. Proband B was born prematurely at 35 weeks gestation with a prenatally diagnosed complex CHD. A postnatal evaluation revealed right-sided heart defects including pulmonary atresia with intact ventricular septum (PA/IVS), right ventricular hypoplasia, tricuspid valve hypoplasia, hypoplastic main and bilateral branch pulmonary arteries, and possible coronary sinusoids. Cardiac catheterization yielded anatomy and hemodynamics unfavorable to repair. Hence, heart transplantation was indicated. Upon genomic testing, a normal SNP microarray was observed, while trio WES analysis identified a novel heterozygous [Chr18:c.1757C>T (p.Pro586Leu)] variant in the GATA6 gene. This variant was inherited from the father, who carries a clinical diagnosis of tetralogy of Fallot. These findings provide new insights into novel GATA5/6 variants, elaborate on the genotypic and phenotypic association, and highlight the critical role of GATA5 and GATA6 transcription factors in a wide spectrum of right-sided CHDs.

Rare diseases are thought to affect a smaller number of people, but together they become a major health concern. Due to advancements in molecular techniques, early diagnosis is essential to the genetic cause of these diseases. This may improve medical care and the survival of affected individuals. Copy number variations or pathogenic single gene mutations are the cause of most of these disorders. Two main rare disease categories were in the focus of our research: congenital heart defects and non-syndromic intellectual disability. Genetic factors, including copy number variations (CNVs), play an important role in the development of CHDs. The most common CNVs are found on chromosome 22q11.2. The genomic instability of this region, caused by the eight low copy repeats (LCR A-H), may result in several recurrent and/or rare microdeletions and duplications, including the most common, ~3Mb large LCR A-D deletion (classical 22q.11.2 deletion syndrome, known as DiGeorge syndrome). Many patients with 22q11.2 CNVs, especially in the adult population may remain undiagnosed due to the high phenotypical variability of these CNVs. Therefore, we aimed to perform a systemic molecular genetic screening for 22q11.2 CNVs in the paediatric and adult patients of the Southern-Hungarian CHD Registry, regardless of the type of their CHDs. All the enrolled participants were cardiologically diagnosed with non-syndromic CHDs. A combination of multiplex ligation-dependent probe amplification, chromosomal microarray analysis and droplet digital PCR methods were used to comprehensively assess the detected 22q11.2 CNVs in overall 212 CHD-patients. Additionally, capillary sequencing was performed to detect variants in the TBX1 gene, a cardinal gene located in 22q11.2. Pathogenic CNVs were detected in 5.2% (11/212), VUS in 0.9% and benign CNVs in 1.8% of the overall CHD cohort. In patients with tetralogy of Fallot the rate of pathogenic CNVs was 17% (5/30). Sixty-four percent of all CNVs were typical proximal deletions (LCR A-D). However, nested (LCR A-B) and central deletions (LCR C-D), proximal (LCR A-D) and distal duplications (LCR D-E, LCR D-H, LCR E-H, LCR F-H) and rare combinations of deletions and duplications were also identified. Segregation analysis detected familial occurrence in 18% (2/11) of the pathogenic variants. Based on in-depth clinical information, a detailed phenotype–genotype comparison was performed. No pathogenic variant was identified in the TBX1 gene, which may question the ethiopathogenetic role of TBX1 mutations alone in the development of CHDs and DiGeorge syndrome. Our findings confirmed the previously described large phenotypic diversity in the 22q11.2 CNVs. MLPA proved to be a highly efficient and cost-effective genetic screening method for our CHD-cohort. Our results highlight the necessity for large-scale genetic screening of CHD-patients and the importance of early genetic diagnosis in their adequate clinical management. In the frame of genetic examinations in X-linked non-syndromic intellectual disabilities we identified a novel mutation in PAK3 gene in a 14-years-old boy. PAK3 is a p21-activated serine/threonine kinase, an essential downstream effector in the Rho-GTPase signaling. It has been reported to play an important role in dendritic spine morphogenesis, synaptic network dynamics and neuronal plasticity. PAK3 gene mutations has been described to cause non-syndromic X-linked intellectual disability with neuropsychiatric disorders and dysmorphic but not distinctive features in the affected individuals. Our patient presented with cognitive impairment, autistic features, temper tantrums, episodic aggression, prior episodes of convulsions, spina bifida occulta, mildly dysmorphic facial features and microcephaly without structural brain abnormalities. Exome sequencing identified a novel hemizygous missense variant in the kinase domain of PAK3 gene (c.976G>C; p.V326L) which is interspecies highly conserved. In silico variant predictions, in silico functional modeling and segregation analysis in the family supported the ethiopathogenicity of the variant. Our detailed clinical findings together with the data from the few reported families allowed further insight in the phenotype of the disease, to expand the mutation spectrum of PAK3 gene and support the importance of PAK3 in neural synaptic function.