OBJECTIVE: To explore the genetic basis for a patient with Dilated cardiomyopathy. METHODS: A patient admitted to Beijing Anzhen Hospital Affiliated to Capital Medical University in April 2022 was selected as the study subject. Clinical data and family history of the patient was collected. Targeted exome sequencing was carried out. Candidate variant was verified by Sanger sequencing and bioinformatic analysis based on guidelines of the American College of Medical Genetics and Genomics (ACMG). RESULTS: DNA sequencing revealed that the patient has harbored a heterozygous c.5044dupG frameshift variant of the FLNC gene. Based on the ACMG guidelines, the variant was predicted to be likely pathogenic (PVS1+PM2_Supporting+PP4). CONCLUSION The heterozygous c.5044dupG variant of the FLNC gene probably underlay the pathogenesis in this patient, which has provided a basis for the genetic counseling for his family.
Humans ; Cardiomyopathy, Dilated/genetics* ; Genetic Testing ; Genetic Counseling ; Computational Biology ; Frameshift Mutation ; Mutation ; Filamins

Adult ; Filamins ; genetics ; Humans ; Male ; Middle Aged ; Muscular Diseases ; genetics ; pathology ; Mutation

OBJECTIVE: To explore the genetic bases of 3 patients with periventricular nodular heterotopia and epileptic seizure. METHODS: The clinical data of three patients presenting with periventricular nodular ectopic with epileptic seizure were analyzed. Whole exome sequencing (WES) was performed on the patients, and Sanger sequencing was used to validate the suspected variants. RESULTS: In three female patients, head MRI showed nodular gray matter ectopic in the bilateral ventricle. WES identified the heterozygous c.2720del T(p.Leu907Argfs*39) variant of FLNA gene in case 1 and her mother (case 2), and heterozygous c.1387_1390del GTGC(p.Val463Profs*34) of FLNA gene in case 3. According to the American College of Medical Genetics and Genomics standards and guidelines, the c.2720delT(p.Leu907Argfs*39) and c.1387_1390del GTGC (p.Val463Profs*34) variants of FLNA gene were predicted to be pathogenic (PVS1+PM2+PP1) and likely pathogenic(PVS1+PM2), respectively. CONCLUSION The c.2720delT(p.Leu907Argfs*39) and c.1387_1390del GTGC(p.Val463Profs*34) variants of FLNA gene may be the genetic cause of the three patients.
Epilepsy/genetics* ; Female ; Filamins/genetics* ; Heterozygote ; Humans ; Magnetic Resonance Imaging ; Mutation ; Periventricular Nodular Heterotopia/genetics* ; Seizures

OBJECTIVE: To explore the clinical and genetic characteristics of a child with frontometaphyseal dysplasia 1 (FMD1) due to variant of FLNA gene. METHODS: Clinical phenotype of the patient was analyzed. Whole exome sequencing (WES) was carried out to detect pathogenic genetic variants. Sanger sequencing was used to verify the result in his parents. RESULTS: The 2-year-and-9-month-old boy presented with facial dysmorphism (supraorbital hyperostosis, down-slanting palpebral fissure and ocular hypertelorism), skeletal deformities (bowed lower limbs, right genu valgum, left genu varus, slight deformity of index and middle fingers, and flexion contracture of little fingers). He also had limited left elbow movement. High-throughput sequencing revealed that he has carried a de novo heterogeneous c.3527G>A (p.Gly1176Glu) missense variant of the FLNA gene. The same variant was found in neither parent. CONCLUSION The clinical manifestations of FMD1 such as joint contracture and bone dysplasia can occur in infancy and deteriorate with age, and require long-term follow-up and treatment. Above finding has expanded the spectrum of FLNA gene variants.
Child ; Filamins/genetics* ; Forehead/abnormalities* ; Humans ; Infant ; Male ; Osteochondrodysplasias/genetics* ; Phenotype ; Whole Exome Sequencing

Adult ; Asian Continental Ancestry Group ; Female ; Filamins ; genetics ; Humans ; Mutation ; genetics ; Periventricular Nodular Heterotopia ; genetics ; pathology

OBJECTIVE: To explore the clinical and genetic characteristics of a fetus with Melnick-Needles syndrome (MNS). METHODS: A fetus with MNS diagnosed at Ningbo Women and Children's Hospital in November 2020 was selected as the study subject. Clinical data was collected. Pathogenic variant was screened by using trio-whole exome sequencing (trio-WES). Candidate variant was verified by Sanger sequencing. RESULTS: Prenatal ultrasonography of the fetus had shown multiple anomalies including intrauterine growth retardation, bilateral femur curvature, omphalocele, single umbilical artery, and oligohydramnios. Trio-WES revealed that the fetus has harbored hemizygous c.3562G>A (p.A1188T) missense variant of the FLNA gene. Sanger sequencing confirmed that the variant was maternally derived, whilst its father was of a wild type. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was predicted to be likely pathogenic (PS4+PM2_Supporting+PP3+PP4). CONCLUSION The hemizygous c.3562G>A (p.A1188T) variant of the FLNA gene probably underlay the structural abnormalities in this fetus. Genetic testing can facilitate accurate diagnosis of MNS and provide a basis for genetic counseling for this family.
Child ; Female ; Humans ; Pregnancy ; Abnormalities, Multiple/genetics* ; Fetal Growth Retardation ; Fetus ; Filamins/genetics* ; Genetic Counseling ; Mutation ; Osteochondrodysplasias

BACKGROUND: Atelosteogenesis type I (AO-I) is a rare lethal skeletal dysplastic disorder characterized by severe short-limbed dwarfism and dislocated hips, knees, and elbows. AO-I is caused by mutations in the filamin B (FLNB) gene; however, several other genes can cause AO-like lethal skeletal dysplasias. METHODS: In order to screen all possible genes associated with AO-like lethal skeletal dysplasias simultaneously, we performed whole-exome sequencing in a female newborn having clinical features of AO-I. RESULTS: Exome sequencing identified a novel missense variant (c.517G>A; p.Ala173Thr) in exon 2 of the FLNB gene in the patient. Sanger sequencing validated this variant, and genetic analysis of the patient's parents suggested a de novo occurrence of the variant. CONCLUSIONS: This study shows that exome sequencing can be a useful tool for the identification of causative mutations in lethal skeletal dysplasia patients.
Exome ; Female ; Filamins/chemistry/*genetics ; Gene Frequency ; Heterozygote ; Humans ; Infant, Newborn ; Mutation, Missense ; Osteochondrodysplasias/*genetics/pathology/radiography ; Polymorphism, Single Nucleotide ; Sequence Analysis, DNA

In resting platelets, the 17 ^th domain of filamin a (FLNa17) constitutively binds to the platelet membrane glycoprotein Ibα (GPIbα) at its cytoplasmic tail (GPIbα-CT) and inhibits the downstream signal activation, while the binding of ligand and blood shear force can activate platelets. To imitate the pull force transmitted from the extracellular ligand of GPIbα and the lateral tension from platelet cytoskeleton deformation, two pulling modes were applied on the GPIbα-CT/FLNa17 complex, and the molecular dynamics simulation method was used to explore the mechanical regulation on the affinity and mechanical stability of the complex. In this study, at first, nine pairs of key hydrogen bonds on the interface between GPIbα-CT and FLNa17 were identified, which was the basis for maintaining the complex structural stability. Secondly, it was found that these hydrogen bonding networks would be broken down and lead to the dissociation of FLNa17 from GPIbα-CT only under the axial pull force; but, under the lateral tension, the secondary structures at both terminals of FLNa17 would unfold to protect the interface of the GPIbα-CT/FLNa17 complex from mechanical damage. In the range of 0~40 pN, the increase of pull force promoted outward-rotation of the nitrogen atom of the 563 ^rd phenylalanine (PHE ⁵⁶³-N) at GPIbα-CT and the dissociation of the complex. This study for the first time revealed that the extracellular ligand-transmitted axial force could more effectively relieve the inhibition of FLNa17 on the downstream signal of GPIbα than pure mechanical tension at the atomic level, and would be useful for further understanding the platelet intracellular force-regulated signal pathway.
Filamins/metabolism* ; Platelet Glycoprotein GPIb-IX Complex/metabolism* ; Molecular Dynamics Simulation ; Ligands ; Protein Binding ; Blood Platelets/metabolism* ; von Willebrand Factor/metabolism*

Filamin A is an actin-binding protein and, in humans, is encoded by FLNA gene in the long arm of X chromosome. Filamin A plays a role in the formation of cytoskeleton by crosslinking actin filaments in cytoplasm. FLNA mutations affect cytoskeletal regulatory processes and cellular migrating abnormalities that result in periventricular heterotopia. A 5-month-old girl was hospitalized because of breathing difficulty and was diagnosed as having periventricular heterotopia with laryngomalacia, cricopharyngeal incoordination, pulmonary hypertension, and chronic lung disease. A genetic test was performed to find the cause of periventricular heterotopia, and FLNA gene mutation (c.5998+1G>A) was confirmed for the first time in Korea. After discharge, she developed respiratory failure due to a viral infection at 8 months of her age. In spite of management with mechanical ventilation, she died of pneumothorax and pulmonary hemorrhage. Herein, we report a case of FLNA gene mutation who presented with periventricular nodular heterotopia with respiratory insufficiency.
Actin Cytoskeleton ; Arm ; Ataxia ; Cytoplasm ; Cytoskeleton ; Female ; Filamins ; Hemorrhage ; Humans ; Hypertension, Pulmonary ; Infant ; Korea ; Laryngomalacia ; Lung Diseases ; Periventricular Nodular Heterotopia ; Pneumothorax ; Respiration ; Respiration, Artificial ; Respiratory Insufficiency ; X Chromosome

Objective: To investigate the effect of adenovirus-mediated shRNA down-regulating phosphatase and tensin homolog deleted on chromosome 10 (PTEN) expression on vinculin, filamin A, and cortactin in activated hepatic stellate cells (HSCs). Methods: Activated rats hepatic stellate cell line (HSC-T6) was cultured in vitro. Recombinant adenovirus Ad-shRNA/PTEN carrying PTEN targeted RNA interference sequence [short hairpin RNA (shRNA)] and empty control virus Ad-GFP were transfected into HSCs. The PTEN mRNA and protein expression of HSCs in each group were detected by real-time fluorescence quantitative PCR and Western blot. The expressional change of vinculin, filamin A and cortactin in HSCs of each group were detected by confocal laser scanning immunofluorescence microscope. Image-pro plus 6.0 software was used for image analysis and processing. The integrated optical density (IOD) of the fluorescence protein expression was measured. The experiment was divided into three groups: control group (DMEM instead of adenovirus solution in the adenovirus transfection step), Ad-GFP group (transfected with empty virus Ad-GFP only expressing green fluorescent protein), and Ad-shRNA/PTEN group (recombinant adenovirus Ad-shRNA/PTEN carrying shRNA targeting PTEN and expressing green fluorescent protein). One-way analysis of variance was used for comparison of mean value among the three groups, and LSD-test was used for comparison between the groups. Results: shRNA targeted PTEN was successfully transfected and the expression of PTEN mRNA and protein in HSC (P < 0.05) was significantly down-regulated. HSCs vinculin was mainly expressed in the cytoplasm. HSCs vinculin fluorescence IOD in the Ad-shRNA/PTEN group (19 758.83 ± 1 520.60) was higher than control (7 737.16 ± 279.93) and Ad-GFP group (7 725.50 ± 373.03) (P < 0.05), but there was no statistically significant difference between control group and Ad-GFP group (P > 0.05). There was no statistically significant difference in the fluorescence IOD of Filamin A among the three groups (P > 0.05), but the subcellular distribution of Filamin A among the three groups were changed. Filamin A in the Ad-shrNA /PTEN HSC group was mainly distributed in the cytoplasm. Filamin A HSC was mainly located in the nucleus.The filamin A HSC in the control group and Ad-GFP group was mainly located in the nucleus. The nucleocytoplasmic ratio of Filamin A in the AD-shrNA /PTEN group (0.60 ± 0.15) was significantly lower than control group (1.20 ± 0.15) and Ad-GFP group (1.08 ± 0.23), P < 0.05. but there was no statistically significant difference in filamin A nucleocytoplasmic ratio of HSC between the control group and the Ad-GFP group (P > 0.05). Cortactin HSCs in the three groups was mainly distributed in the cytoplasm. The cortactin fluorescence IOD of HSCs in the Ad-shRNA/PTEN group was significantly higher than control group (22 959.94 ± 1 710.42) and the Ad-GFP group (22 547.11 ± 1 588.72 ) (P < 0.05), while there was no statistically significant difference in the IOD of cortactin fluorescence in HSCs between the control group and the Ad-GFP group (P > 0.05). Conclusion: The down-regulation of PTEN expression raises the expression of microfilament-binding protein vinculin and cortactin, and changes the subcellular distribution of another microfilament binding protein filamin A, that is, translocation from nucleus to the cytoplasm in activated HSC in vitro.
Adenoviridae/metabolism* ; Animals ; Carrier Proteins ; Cell Proliferation ; Cortactin ; Filamins/genetics* ; Hepatic Stellate Cells/metabolism* ; PTEN Phosphohydrolase/metabolism* ; RNA, Small Interfering/genetics* ; Rats ; Vinculin/genetics*