Search Results (11)

Background Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an autosomal dominant neurological disorder caused by mutations in the NOTCH3 gene. Disease-causing variants in NOTCH3 are primarily missense variants altering the number of cysteine residues in the translated NOTCH3 protein. The genetic screening of the NOTCH3 gene is currently considered the gold standard for CADASIL diagnosis. Methods The Genomics Research Centre has been performing diagnostic genetic testing for CADASIL since 1997. A total of 1281 patient samples suspected of having CADASIL were screened for NOTCH3 mutations from January 1, 1997, to October 1, 2025. Genomic sequencing was performed using Sanger sequencing of selected NOTCH3 exons or using next-generation sequencing to screen the entire NOTCH3 gene. Results In total, 12.1% of patients had a cysteine-altering NOTCH3 variant, including 49 variants in exons 2-24, and two variants in non-EGFr encoding exons. We also report the first CADASIL patient who is a compound heterozygote for two known pathogenic cysteine-altering NOTCH3 variants, who presented with a severe early onset of stroke, migraine, and white matter changes. Conclusions The compound heterozygosity identified in this patient appears to be associated with an early onset of CADASIL symptoms. Our study contributes to the elucidation of the spectrum of NOTCH3 variants associated with CADASIL. The majority of patients tested for CADASIL in this study did not contain a variant in NOTCH3, indicating that there are other genes or genetic variants contributing to disease in these patients. Full article

Background/Objectives: The most prevalent form of neurodegeneration with brain iron accumulation (NBIA) is pantothenate kinase-associated neurodegeneration (PKAN), caused by mutations in the PANK2 gene. The hallmark of PKAN is the “eye-of-the-tiger” sign, which is characterized by a bilateral region of central hyperintense signal surrounded by a hypointense signal in the medial globus pallidus on T2-weighted brain magnetic resonance imaging (MRI). Methods: Whole-exome sequencing (WES) was performed in four patients who presented with dystonia, cognitive impairment and abnormalities of the globus pallidus. All patients underwent comprehensive clinical and instrumental evaluations. Results: Molecular analysis using WES revealed PANK2 variants in all four cases. Two patients were homozygous for the known pathogenic variant c.1169A > T (p.N390I). The remaining two patients displayed compound heterozygotes, each carrying the novel splicing variant c.906-1G > A on one allele, combined with a different second variant on the other allele: the new missense variant c.617G > A (p.G206D) in one case and the known pathogenic variant c.1231G > A (p.G411R) in the other. In one case, brain imaging documented the transition from initial hyperintensity of the globus pallidus to the development of the “eye-of-the-tiger” sign. In two cases, MRI findings clearly demonstrated the characteristic “eye-of-the-tiger” appearance. Ultimately, in one case, the imaging likely captured a later disease stage, in which the “eye-of-the-tiger” sign was no longer visible, and only the residual hypointensity remained. Conclusions: This study describes two novel likely pathogenic variants and documents the full MRI progression of globus pallidus involvement in PKAN. The sequence starts with early T2 hyperintensity, followed by the emergence of the typical “eye-of-the-tiger” sign, and culminates in marked hypointensity in advanced stages. Since the initial clinical presentation may mimic mitochondrial disorders or other neurometabolic conditions, these imaging features are crucial for guiding differential diagnosis and enabling accurate disease identification. Full article

Inherited defects in the genes of blood coagulation essentially express the severity of the clinical phenotype that is directly correlated to the number of mutated alleles of the candidate leader gene (e.g., heterozygote vs. homozygote) and of possible additional coinherited traits. The F5 gene, which codes for coagulation factor V (FV), plays a two-faced role in the coagulation cascade, exhibiting both procoagulant and anticoagulant functions. Thus, defects in this gene can be predisposed to either bleeding or thrombosis. A Sanger sequence analysis detected a premature stop-codon in exon 13 of the F5 gene (c.3481C>T; p.R1161Ter) in several members of a family characterised by low circulating FV levels and contrasting clinical phenotypes. The propositus, a 29 y.o. male affected by recurrent haemorrhages, was homozygous for the F5 stop-codon and for the F5 c.1691G>A (p.R506Q; FV-Leiden) inherited from the heterozygous parents, which is suggestive of combined cis-segregation. The homozygous condition of the stop-codon completely abolished the F5 gene expression in the propositus (FV:Ag < 1%; FV:C < 1%; assessed by ELISA and PT-based one-stage clotting assay respectively), removing, in turn, any chance for FV-Leiden to act as a prothrombotic molecule. His father (57 y.o.), characterised by severe recurrent venous thromboses, underwent a complete molecular thrombophilic screening, revealing a heterozygous F2 G20210A defect, while his mother (56 y.o.), who was negative for further common coagulation defects, reported fully asymptomatic anamnesis. To dissect these conflicting phenotypes, we performed the ProC^®Global (Siemens Helthineers) coagulation test aimed at assessing the global pro- and anticoagulant balance of each family member, investigating the responses to the activated protein C (APC) by means of an APC-sensitivity ratio (APC-sr). The propositus had an unexpectedly poor response to APC (APC-sr: 1.09; n.v. > 2.25), and his father and mother had an APC-sr of 1.5 and 2.0, respectively. Although ProC^®Global prevalently detects the anticoagulant side of FV, the exceptionally low APC-sr of the propositus and his discordant severe–moderate haemorrhagic phenotype could suggest a residual expression of mutated FV p.506QQ through a natural readthrough or possible alternative splicing mechanisms. The coagulation pathway may be physiologically rebalanced through natural and induced strategies, and the described insights might be able to track the design of novel treatment approaches and rebalancing molecules. Full article

3beta-hydroxysteroid dehydrogenase type II deficiency (HSD3B2 deficiency), a rare form of congenital adrenal hyperplasia (CAH), is characterized by varying degrees of salt loss and incomplete masculinization in males and mild virilization or normal external genitalia in females. We report the case of a patient (46XY) showing salt loss and incomplete masculinization, markedly elevated levels of 17OHP (17 hydroxyprogesterone), ACTH (Adreno Cortico Tropic Hormone), testosterone and delta4androstenedione (delta4A), low levels of cortisol and absence of bone skeletal alterations that frequently characterize POR (Cytochrome P450 oxidoreductase) deficiency. Mutation analysis by Sanger sequencing of the HSD3B2 gene showed that the patient presented with a compound heterozygote for two novel variants c.370A>G p.Ser124Gly and c.308-6 G>A. The two HSD3B2 gene variants were also present in the patient’s older brother showing only incomplete masculinization. The in silico analysis revealed a probable damaging effect of c.370A>G p.Ser124Gly: residue p.Ser124 is highly conserved among species and seems to be located in the catalytic site of the enzyme, playing a pivotal role in NAD(H) binding to its substrate. Intronic c.308-6G>A variant is predicted to be likely pathogenic; the substitution seems to cause a change in the splice acceptor site located 6bp downstream of the variant. The two siblings seem to be affected by 3β-HSD2 deficiency; nevertheless, the two novel variants are likely to cause variable expressivity of the disease. Full article

The myosin molecular motor interacts with actin filaments in an ATP-dependent manner to yield muscle contraction. Myosin heavy chain residue R369 is located within loop 4 at the actin-tropomyosin interface of myosin’s upper 50 kDa subdomain. To probe the importance of R369, we introduced a histidine mutation of that residue into Drosophila myosin and implemented an integrative approach to determine effects at the biochemical, cellular, and whole organism levels. Substituting the similarly charged but bulkier histidine residue reduces maximal actin binding in vitro without affecting myosin ATPase activity. R369H mutants exhibit impaired flight ability that is dominant in heterozygotes and progressive with age in homozygotes. Indirect flight muscle ultrastructure is normal in mutant homozygotes, suggesting that assembly defects or structural deterioration of myofibrils are not causative of reduced flight. Jump ability is also reduced in homozygotes. In contrast to these skeletal muscle defects, R369H mutants show normal heart ultrastructure and function, suggesting that this residue is differentially sensitive to perturbation in different myosin isoforms or muscle types. Overall, our findings indicate that R369 is an actin binding residue that is critical for myosin function in skeletal muscles, and suggest that more severe perturbations at this residue may cause human myopathies through a similar mechanism. Full article

Grains number is one of the most important agronomic traits in the determination of rice productivity. To explore the underlying genetic basis of grain number in rice, quantitative trait locus (QTL) analysis was performed using three recombinant inbred line populations derived from indica rice crosses of Teqing/IRBB lines, Zhenshan 97/Milyang 46, and Xieqingzao/Milyang 46, respectively. A total of 58 QTLs distributed on all 12 rice chromosomes were identified, including 22 for number of grains per panicle (NGP), 17 for number of spikelets per panicle, and 19 for spikelet fertility. The individual QTL counted for 1.5 to 22.1% of phenotypic variation. Among them, 15 QTLs shared by two or three populations and eight QTLs showed large effects with R² larger than 10%. Furthermore, three QTLs with minor effects for NGP, qNGP5.5, qNGP9.1, and qNGP12.1, were detected and validated by eliminating the segregation of major-effect QTL using four residual heterozygote-derived populations. These results not only enrich our understanding of the mechanism of grain number, but also provide a foundation for cloning and selecting candidate for marker-assisted selection breeding in rice. Full article

To clarify the genetic mechanism underlying grain protein content (GPC) and to improve rice grain qualities, the mapping and cloning of quantitative trait loci (QTLs) controlling the natural variation of GPC are very important. Based on genotyping-by-resequencing, a total of 14 QTLs were detected with the Huanghuazhan/Jizi1560 (HHZ/JZ1560) recombinant inbred line (RIL) population in 2016 and 2017. Seven of the fourteen QTLs were repeatedly identified across two years. Using three residual heterozygote-derived populations, a stably inherited QTL named as qGPC1-1 was validated and delimited to a ~862 kb marker interval JD1006–JD1075 on the short arm of chromosome 1. Comparing the GPC values of the RIL population determined by near infrared reflectance spectroscopy (NIRS) and Kjeldahl nitrogen determination (KND) methods, high correlation coefficients (0.966 and 0.983) were observed in 2016 and 2017. Furthermore, 12 of the 14 QTLs were identically identified with the GPC measured by the two methods. These results indicated that instead of the traditional KND method, the rapid and easy-to-operate NIRS was suitable for analyzing a massive number of samples in mapping and cloning QTLs for GPC. Using the gel-based low-density map consisted of 208 simple sequence repeat (SSR) and insert/deletion (InDel) markers, the same number of QTLs (fourteen) were identified in the same HHZ/JZ1560 RIL population, and three QTLs were repeatedly detected across two years. More stably expressed QTLs were identified based on the genome resequencing, which might be attributed to the high-density map, increasing the detection power of minor QTLs. Our results are helpful in dissecting the genetic basis of GPC and improving rice grain qualities through molecular assisted selection. Full article

Sweden has 10.2 million inhabitants and more than 2.4 million have a foreign background. A substantial number of immigrants come from countries where glucose-6-phosphate dehydrogenase deficiency (G6PDD) is frequent. The total birth rate annually in Sweden is approximately 117,000 and newborn screening is centralized to one laboratory. We determined glucose-6-phosphate dehydrogenase (G6PD) activity in 10,098 dried blood spot samples (DBS) from the whole country with a fluorometric assay (LabSystems Diagnostics Oy, Finland). The first 5451 samples were anonymised and run as singletons, whilst the following 4647 samples were coded. Enzyme activity ≤40% of the mean of the day was found in 58 samples (1/170) and among these, 29 had activities ≤10% (1/350). Twenty-nine samples with residual activities between 2–39% in the coded cohort were subjected to Sanger sequencing. Disease-causing variants were identified in 26 out of 29 infants, of which six were girls. In three patients, we did not find any disease-causing variants, although two patients were hemizygous for the known polymorphisms c.1311T>C and c.1365-13C>T. The most common disease-causing variant found in 15 of the 29 samples (12 hemizygotes, two heterozygotes, one homozygote) was the Mediterranean mutation, c.563C>T (p.(Ser188Phe)) in exon 6. G6PDD is thus a surprisingly prevalent disorder in Sweden. Full article

In molecular breeding of super rice, it is essential to isolate the best quantitative trait loci (QTLs) and genes of leaf shape and explore yield potential using large germplasm collections and genetic populations. In this study, a recombinant inbred line (RIL) population was used, which was derived from a cross between the following parental lines: hybrid rice Chunyou84, that is, japonica maintainer line Chunjiang16B (CJ16); and indica restorer line Chunhui 84 (C84) with remarkable leaf morphological differences. QTLs mapping of leaf shape traits was analyzed at the heading stage under different environmental conditions in Hainan (HN) and Hangzhou (HZ). A major QTL qLL9 for leaf length was detected and its function was studied using a population derived from a single residual heterozygote (RH), which was identified in the original population. qLL9 was delimitated to a 16.17 kb region flanked by molecular markers C-1640 and C-1642, which contained three open reading frames (ORFs). We found that the candidate gene for qLL9 is allelic to DEP1 using quantitative real-time polymerase chain reaction (qRT-PCR), sequence comparison, and the clustered regularly interspaced short palindromic repeat-associated Cas9 nuclease (CRISPR/Cas9) genome editing techniques. To identify the effect of qLL9 on yield, leaf shape and grain traits were measured in near isogenic lines (NILs) NIL-qLL9^CJ16 and NIL-qLL9^C84, as well as a chromosome segment substitution line (CSSL) CSSL-qLL9^KASA with a Kasalath introgressed segment covering qLL9 in the Wuyunjing (WYJ) 7 backgrounds. Our results showed that the flag leaf lengths of NIL-qLL9^C84 and CSSL-qLL9^KASA were significantly different from those of NIL-qLL9^CJ16 and WYJ 7, respectively. Compared with NIL-qLL9^CJ16, the spike length, grain size, and thousand-grain weight of NIL-qLL9^C84 were significantly higher, resulting in a significant increase in yield of 15.08%. Exploring and pyramiding beneficial genes resembling qLL9^C84 for super rice breeding could increase both the source (e.g., leaf length and leaf area) and the sink (e.g., yield traits). This study provides a foundation for future investigation of the molecular mechanisms underlying the source–sink balance and high-yield potential of rice, benefiting high-yield molecular design breeding for global food security. Full article

KIF5A encodes the heavy chain A of kinesin; A motor protein involved in motility functions within neuron. Mutations in the KIF5A N-terminal motor domain are known to cause SPG10; An autosomal dominant hereditary spastic paraplegia (HSP), as well as rare Charcot-Marie-Tooth disease 2 (CMT2) cases. Recently C-terminal cargo-binding tail domain mutations have been associated with an amyotrophic lateral sclerosis (ALS) phenotype. Here we describe a subject presenting with an atypical slowly progressive motor syndrome evolving over a period of 4 years; Characterized by walking difficulties; Muscle hypotrophy mainly involving upper limbs and pyramidal signs confined to the lower limbs. Electromyography demonstrated chronic neurogenic damage and active denervation while electroneurography showed slowly worsening axonal damage. We identified the novel heterozygote variant c.2341A>G in the exon 21 of the KIF5A gene resulting in the amino acid change p.Lys781Glu. The residue Lys781 is located within the terminal region of the stalk domain and is highly evolutionary conserved. Our findings confirm that mutations in KIF5A cause ALS-like phenotypes. However, the stalk domain mutation described here appears to result in an “intermediate” slowly progressive phenotype having aspects resembling ALS as well as HSP and axonal neuropathy. We suggest that KIF5A gene should be considered as a candidate gene in all atypical progressive motor syndromes. Full article

Sickle cell disease (SCD) is an inherited, lifelong condition. The sickle mutation consists a single nucleotide change (GAT->GTT) in the sixth codon of exon 1 of the β-globin gene coding for the β-globin polypeptide of hemoglobin (Hb) (a₂β₂). This change results in replacement of the wild type glutamic acid residue by a valine residue in β-globin chain and the formation of the sickle Hb (HbS) in homozygotes for this mutation. Heterozygotes live a normal life. In SCD patients, sickle erythrocytes are rigid with decreased deformability and reduced life span resulting in hemolysis, vaso-occlusive disease, vasculopathy and subsequent inflammation and end organ damage. Sickle cell disease affects millions of people worldwide. Today, with proper health care, many SCD patients have a good quality of life (QoL) and are in fairly good health most of the time. These people can live up to their forties or fifties, or longer. Despite the ‘common’ underlying genetic basis and a similar pathophysiology, patients with SCD present a highly variable clinical phenotype due to Single Nucleotide Polymorphisms (SNPs) variability throughout the genome. Patients with SCD are at high risk for developing multisystem acute and chronic complications associated with significant morbidity and mortality. Full article