UNASSIGNED: Acromelic dysplasia caused by FBN1 mutation includes acromicric dysplasia (AD), geleophysic dysplasia 2 (GD2), and Weill-Marchesani syndrome 2 (WMS2). All three diseases share severe short stature and brachydactyly. Besides phenotypic similarity, there is a molecular genetic overlap among them, as identical FBN1 gene mutations have been identified in patients with AD, GD2, and WMS2. However, no family with different acromelic dysplasia phenotypes due to the same variant has been described in English reports.
UNASSIGNED: The proband presented with typical facial features, severe short stature, short limbs, stubby hands and feet and radiological abnormalities. Her elder sister and mother had similar physical features. In addition, her elder sister was found to have aortic valve stenosis by echocardiography. Mutation analysis demonstrated a heterozygous missense mutation, c.5179C>T (p.Arg1727Trp) in exon 42 of the FBN1. The proband and her mother were diagnosed with AD, and her elder sister with GD2. The proband was treated with recombinant human growth hormone (rhGH) and had a body length gain of 0.72 SDS in half a year.
UNASSIGNED: These findings expand the phenotypic spectrum of FBN1 gene mutations and highlight that identical FBN1 genotypes can result in different phenotypes of acromelic dysplasia in a family. The efficacy of rhGH therapy in patients with acromelic dysplasia is controversial. More follow-up is needed on the long-term efficacy of rhGH therapy.

UNASSIGNED: Pulmonary alveolar microlithiasis (PAM) is a rare disease whose clinical and imaging manifestations are non-specific, characterized by the deposition of microliths, which primarily consist of calcium and phosphorus, within the alveoli. In the cases of PAM, patients combined with calcification of other organs such as gastric mucosal calcification are less common.
UNASSIGNED: A 59-year-old woman was admitted to our hospital due to cough producing white, foamy sputum, accompanied by dyspnea and fever for 20 days. The CT scan showed diffuse ground-glass opacities and calcification of the gastric mucosa. Lung tissue biopsy revealed the presence of calcification and granulomatous foreign bodies in the interstitium and alveolar cavity. In the later stages, she developed painful skin petechiae. For this patient, the diagnosis of PAM, gastric mucosal calcification, and purpura fulminans was made. However, the genetic test results hinted that the patient and her son had a heterozygous mutation in the FBN1 gene, but her daughter\'s genetic test results were normal. Although the patient received anti-infection treatment, steroids, and oxygen therapy, her condition did not improve.
UNASSIGNED: We reported a rare case of PAM combined with calcification of other organs and purpura fulminans. Treatment of steroids did not show any benefit. The causative mechanism and effective treatment of this disease remain unclear. More treatments need to be explored.

UNASSIGNED: Marfan syndrome (MFS) is an autosomal dominant genetic disorder caused by pathogenic variants of the fibrillin-1-encoding FBN1 gene that commonly affects the cardiovascular, skeletal, and ocular systems. This study aimed to evaluate the clinical features and genetic causes of the MFS phenotype in a large Iranian family.
UNASSIGNED: Seventeen affected family members were examined clinically by cardiologists and ophthalmologists. The proband, a 48-year-old woman with obvious signs of MFS, her DNA sample subjected to whole-exome sequencing (WES). The candidate variant was validated by bidirectional sequencing of proband and other available family members. In silico analysis and molecular modeling were conducted to determine the pathogenic effects of the candidate variants.
UNASSIGNED: The most frequent cardiac complications are mitral valve prolapse and regurgitation. Ophthalmic examination revealed iridodonesis and ectopic lentis. A heterozygous missense variant (c.2179T>C/p.C727R) in exon 19 of FBN1 gene was identified and found to cosegregate with affected family members. Its pathogenicity has been predicted using several in silico predictive algorithms. Molecular docking analysis indicated that the variant might affect the binding affinity between FBN1 and LTBP1 proteins by impairing disulfide bond formation.
UNASSIGNED: Our report expands the spectrum of the Marfan phenotype by providing details of its clinical manifestations and disease-associated molecular changes. It also highlights the value of WES in genetic diagnosis and contributes to genetic counseling in families with MFS.

Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder due to pathogenic variants in Fibrillin-1 (FBN1) affecting nearly one in every 10,000 individuals. We report a 16-month-old female with early-onset MFS heterozygous for an 11.2 kb de novo duplication within the FBN1 gene. Tandem location of the duplication was further confirmed by optical genome mapping in addition to genetic sequencing and chromosomal microarray. This is the third reported case of a large multi-exon duplication in FBN1, and the only one confirmed to be in tandem. As the vast majority of pathogenic variants associated with MFS are point mutations, this expands the landscape of known FBN1 pathogenic variants and supports consistent use of genetic testing strategies that can detect large, indel-type variants.

Optical genome mapping (OGM), which allows analysis of ultra-high molecular weight (UHMW) DNA molecules, represents a response to the restriction created by short-read next-generation-sequencing, even in cases where the causative variant is a neutral copy-number-variant insensitive to quantitative investigations. This study aimed to provide a molecular diagnosis to a boy with Marfan syndrome (MFS) and intellectual disability (ID) carrying a de novo translocation involving chromosomes 3, 4, and 13 and a 1.7 Mb deletion at the breakpoint of chromosome 3. No FBN1 alteration explaining his Marfan phenotype was highlighted. UHMW gDNA was isolated from both the patient and his parents and processed using OGM. Genome assembly was followed by variant calling and annotation. Multiple strategies confirmed the results. The 3p deletion, which disrupted ROBO2, (MIM*602431) included three copy-neutral insertions. Two came from chromosome 13; the third contained 15q21.1, including the FBN1 from intron-45 onwards, thus explaining the MFS phenotype. We could not attribute the ID to a specific gene variant nor to the reshuffling of topologically associating domains (TADs). Our patient did not have vesicular reflux-2, as reported by missense alterations of ROBO2 (VUR2, MIM#610878), implying that reduced expression of all or some isoforms has a different effect than some of the point mutations. Indeed, the ROBO2 expression pattern and its role as an axon-guide suggests that its partial deletion is responsible for the patient\'s neurological phenotype. Conclusion: OGM testing 1) highlights copy-neutral variants that could remain invisible if no loss of heterozygosity is observed and 2) is mandatory before other molecular studies in the presence of any chromosomal rearrangement for an accurate genotype-phenotype relationship.

UNASSIGNED: Marfan syndrome is a potentially fatal inherited autosomal dominant condition impacting the cardiovascular and the skeletal system with an estimated 25% cases caused by sporadic genetic variations. Given the genetic inheritance pattern, an autopsy of probands with Marfan syndrome-associated mortality is critical to establish the phenotypic expression and clinical implications of the particular genetic variant, especially for first-degree relatives. We present the findings of a Marfan syndrome proband decedent presenting with sudden onset abdominal pain and unexplained retroperitoneal abdominal hemorrhage.
UNASSIGNED: An autopsy was performed to inform the blood relatives of the phenotypic expression and penetrance of the potentially heritable condition. A clinical laboratory improvement amendment (CLIA)-certified clinical grade genetic sequencing was performed to identify pathogenic variants in genes associated with aortopathy.
UNASSIGNED: The autopsy showed intra-abdominal and retroperitoneal hemorrhage due to infarction of the right kidney caused by dissection of the right renal artery. Genetic testing identified a heterozygous pathogenic FBN1 gene variant. The specific variant is FBN1 NM_000138.4 c.2953G > A p.(Gly985Arg).
UNASSIGNED: We report a case of a previously undiagnosed Marfan syndrome death due to a de novo FBN1 variant, c.2953G > A.

Marfan syndrome (MFS) is a rare autosomal dominant connective tissue disorder affecting the cardiovascular, skeletal, and ophthalmic systems. This report aimed to describe a novel genetic background and treatment prognosis of MFS.
A proband was initially diagnosed with bilateral pathologic myopia and suspected MFS. We performed whole exome sequencing and found a pathogenic nonsense FBN1 mutation in the proband, which confirmed the diagnosis of MFS. Notably, we identified a second pathogenic nonsense mutation in SDHB, which increased the risk of tumours. In addition, the proband karyotype was X trisomy, which may cause X trisomy syndrome. At the 6-month follow-up after posterior scleral reinforcement surgery, the proband\'s visual acuity improved significantly; however, myopia was still progressing.
We report a rare case of MFS with a X trisomy genotype, a mutation in FBN1 and a mutation in SDHB for the first time, and our findings could be helpful for the clinical diagnosis and treatment of this disease.

Marfan syndrome (MFS) is a life-threatening autosomal dominant genetic disorder of connective tissue caused by the pathogenic mutation of FBN1. Whole exome sequencing and Sanger sequencing were performed to identify the pathogenic mutation. The transcriptional consequence of the splice-altering mutation was analyzed via minigene assays and reverse-transcription PCR. We identified a novel pathogenic mutation (c.8051+1G>C) in the splice site of exon 64 of the FBN1 gene in an MFS-pedigree. This mutation was confirmed to cause two different truncated transcripts (entire exon 64 skipping; partial exon 64 exclusion). We also systematically summarized previously reported transcriptional studies of pathogenic splice-altering mutations in the FBN1 gene to investigate the clinical and transcriptional consequences. In conclusion, we reported for the first time that a splice-altering mutation in the FBN1 gene leads to two abnormal transcripts simultaneously.

Marfan syndrome, an autosomal dominant disorder of connective tissue, is primarily caused by mutations in the fibrillin-1 (FBN1) gene, which encodes the protein fibrillin-1. The protein is composed of epidermal growth factor-like (EGF-like) domains, transforming growth factor beta-binding protein-like (TB) domains, and hybrid (Hyb) domains and is an important component of elastin-related microfibrils in elastic fiber tissue. In this study, we report a cysteine to tyrosine substitution in two different domains of fibrillin-1, both of which cause Marfan syndrome with ocular abnormalities, in two families. Using protease degradation and liquid chromatography-tandem mass spectrometry analyses, we explored the different effects of substitution of cysteine by tyrosine in an EGF-like and a calcium-binding (cb) EGF-like domain on protein stability. The results showed that cysteine mutations in the EGF domain are more likely to result in altered proteolytic sensitivity and thermostability than those in the cbEGF domain. Furthermore, cysteine mutations can lead to new enzymatic sites exposure or hidden canonical cleavage sites. These results indicate the differential clinical phenotypes and molecular pathogenesis of Marfan syndrome caused by cysteine mutations in different fibrillin-1 domains. These results strongly suggest that failure to form disulfide bonds and abnormal proteolysis of fibrillin-1 caused by cysteine mutations may be an important factor underlying the pathogenesis of diseases caused by fibrillin-1 mutations, such as Marfan syndrome.

UNASSIGNED: Marfan syndrome (MFS) is an autosomal dominant multisystem connective tissue disorder with increased risk of aortopathy with a high risk of subsequent life-threatening aortic dissection. Diagnosing this condition is reliant on recognizing clinical features and genetic testing for confirming diagnosis, using the revised Ghent criteria.
UNASSIGNED: We identified a 49-year-old patient who presented with dyspnoea, with Marfan syndrome (MFS) and a previously unreported variant in the fibrillin-1 gene (FBN1), designated c.7016G>C. Prior to identifying the new gene variant, this patient did not meet the revised Ghent criteria for MFS diagnosis. We present clinical and molecular evidence supporting the likely pathogenic nature of this variant, leading to earlier therapy and intervention.
UNASSIGNED: The discovery of a new pathogenic gene will expand the current aortopathy and MFS database and may lead to more informed clinical management decisions for the timing and nature of interventions.