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.

BACKGROUND: Marfan syndrome (MFS) is a rare autosomal dominant connective tissue disorder. Diagnosing MFS can be challenging as the disease\'s severity and clinical manifestations differ between pathogenic variants, and because a lack of published information currently exists on phenotype-genotype correlations. This report aims to underline the clinical manifestations associated with fibrillin-1 (FBN1) gene mutations by assessing MFS in 6 families from China.
METHODS: We diagnosed 6 patients and their relatives with MFS by combining a clinical examination (based on the 2010 revised Ghent nosology criteria) with a targeted next-generation sequencing analysis. The functional analysis of the causal mutations and clinical details of the affected patients were then assessed.
RESULTS: We identified 6 pathogenic mutations in FBN1, including 1 novel frameshift, 1 nonsense, and 4 missense mutations. Most uniquely, mitral valve prolapses (MVP) and ectopia lentis (EL) were found in the cysteine-related mutations. Typically, facial symptoms of MFS are observed in frameshift or nonsense mutants, not in cysteine-related ones. Furthermore, the patients with premature terminal codons had a more serious skin condition than patients with missense mutations, partly indicating the important effect FBN1 has on skin.
CONCLUSIONS: This study expands the mutation spectrum of MFS and highlights possible genotype-phenotype correlations, thereby improving the early diagnosis and symptomatic treatment of the disease.

BACKGROUND: Marfan syndrome (MFS) has been defined as a genetic disorder that affects various systems such as the musculoskeletal, orbital, and cardiovascular systems. Neonatal MFS is considered rare and the most severe form of MFS is characterized by rapidly progressive atrioventricular valve dysfunction, often leading to death during early childhood due to congestive heart failure.
METHODS: A newborn with neonatal MFS and severe cardiac involvement. He presented various severe clinical features such as arachnodactyly, camptodactyly, elbow and knee joint contracture, senile facial appearance, and deep settling with down-slanting palpebral fissure, hypoplastic ear cartilage, sagging mouth, brachycephaly, and ectopia lentis.
METHODS: Genetic analysis revealed a novel mutation at nucleotide 3964 (c.3964 + 1 G > T) in intron 32 of the fibrillin-1 gene. This mutation is identified to be in the so-called neonatal region of fibrillin-1 exon 24 to 32, as reported previously.
METHODS: The patient was managed medically for improving the low cardiac output according to severe mitral regurgitation and aortic regurgitation. Afterload reduction, full sedation, and use of diuretic were attempted to improve the oliguria and heart failure.
RESULTS: Despite the medical management, aortic regurgitation, mitral regurgitation, pulmonary hypertension, and cardiac contractility got worse. Surgical treatment is essential to prolong the patient\'s life, however, considerations for the grave progression of the disease make families decide to continue palliative care instead of surgical treatment. A few months after birth, he presented with rapidly progressive aortic regurgitation, mitral regurgitation, and congestive heart failure leading to death.
CONCLUSIONS: This review demonstrated the prominent characteristics of neonatal MFS mutations, it would be helpful for the recognition of novel neonatal MFS variants and valuable for the understanding of the genotype-phenotype correlations and using the plans for managements and counseling in neonatal MFS.

Marfan Syndrome (MFS) is an autosomal dominant connective tissue disorder with a wide range of severities. Ninety-five percent of MFS probands have a mutation in the fibrillin-1 gene (FBN1); however, there are a high number of unique mutations complicating attempts at establishing any phenotype-genotype correlations for this disease (Tiecke et al., European Journal of Human Genetics, 2001, 9, 13-21). One of the few extant genotype-phenotype correlations is in exon 24-32 which have been associated with a severe pediatric presentation of neonatal MFS with predominately cardiovascular symptoms. We present a 24-year-old male patient with a heterozygous de novo variant NM_000138.4: c.3037G>A (p.G1013R) located in exon 25 of the FBN1 gene. The patient was found to have dysplastic mitral and tricuspid valves with dilated aortic root at 9 months of age. This is a notable case in that the location of this patient\'s mutation and his age of symptom onset would indicate a guarded prognosis. Further, this mutation, FBN1 G1013R, has been reported in the literature in four other unrelated patients all of whom presented at a young age with cardiac involvement and all of whom had relative longevity when compared to other patients with mutations in this exon 24-32 hot spot. These findings may represent a more specific genotype-phenotype correlation within this mutational hot spot.

BACKGROUND: FBN1 (15q21.1) encodes fibrillin-1, a large glycoprotein which is a major component of microfibrils that are widely distributed in structural elements of elastic and non-elastic tissues. FBN1 variants are responsible for the related connective tissue disorders, grouped under the generic term of type-1 fibrillinopathies, which include Marfan syndrome (MFS), MASS syndrome (Mitral valve prolapse, Aortic enlargement, Skin and Skeletal findings, Acromicric dysplasia, Familial ectopia lentis, Geleophysic dysplasia 2, Stiff skin syndrome, and dominant Weill-Marchesani syndrome.
METHODS: Two siblings presented with isolated skeletal manifestations of MFS, including severe pectus excavatum, elongated face, scoliosis in one case, and absence of other clinical features according to Ghent criteria diagnosis, were screened for detection of variants in whole FBN1 gene (65 exons). Both individuals were heterozygous for the R2726W variant. This variant has been previously reported in association with some skeletal features of Marfan syndrome in the absence of both tall stature and non-skeletal features. These features are consistent with the presentation of the siblings reported here.
CONCLUSIONS: The presented cases confirm that the R2726W FBN1 variant is associated with skeletal features of MFS in the absence of cardiac or ocular findings. These findings confirm that FBN1 variants are associated with a broad phenotypic spectrum and the value of sequencing in atypical cases.

Chest pain is the second most common reason for referral to a pediatric cardiologist, because cardiovascular-related disorders are a major concern for children and their families when seeking medical attention. On the rare occasions when pediatric chest pain is a result of severe heart disease, it is usually associated with well-known cardiovascular risk factors such as fibrillinopathies. Type 1 fibrillinopathies are heritable disorders caused by mutations in the fibrillin genes that lead to a broad spectrum of connective tissue phenotypes ranging from Marfan syndrome, at the most severe end, to patients displaying mild marfanoid features, or milder Marfan (MM). We report the case of an adolescent patient with MM and suspected acute coronary syndrome, with chest pain and electrocardiographic changes suggestive of myocardial ischemia. Despite the low risk of coronary or aortic dissection/aneurysm in MM, these possibilities should be tested. Once they are ruled out, mitral valve prolapse should be considered as the main cause of chest pain with ischemic-like changes in the inferior electrocardiogram leads. We emphasize that clinical and echocardiographic follow-up over years is warranted in the pediatric population to ensure that the aortic root does not show progressive dilatation or a tendency to dissect. Finally, genotyping is clinically indicated for early and complete diagnosis in patients with MM as well as de novo Marfan syndrome to take advantage of educational and clinical programs for young carriers of the mutation.

Congenital contractural arachnodactyly (CCA) is a connective tissue disease caused by mutations of the FBN2, which encodes fibrillin-2. CCA patients have a marfanoid habitus; however, aortic dilatation and/or dissection as observed in Marfan syndrome have been rarely documented. Here, we report on a Japanese familial case of CCA resulting from a FBN2 splicing mutation (IVS32+5g→a), which leads to exon 32 being skipped, and the patients developed aortic dilatation and type A dissection. Although CCA patients have been believed to have favorable prognoses, repetitive aortic imaging studies must be performed in some patients to detect possible aortic disease early, and genetic testing of FBN2 might be useful to identify such high-risk patients.

A 39-year-old man was admitted to our hospital because of left frontal subcortical hemorrhage.When he was 22, he underwent an operation for aortic dilatation and aortic valve regurgitation, and he had been taking warfarin since then. At that hospital, he was diagnosed with Marfan syndrome (MFS) on the basis of his clinical features, but the diagnosis was not confirmed genetically. Head radiological imaging did not reveal the abnormal blood vessels causing subcortical hemorrhage, but T2* magnetic resonance imaging showed many micro-bleeds in the subcortical areas and basal ganglia. Moreover, cerebral angiography showed marked tortuous carotid and vertebral both arteries in his neck; these findings suggested the possibility of Loeys-Dietz syndrome. Genetic analysis revealed a single-base substitution (c.3713-3C>G) at the -3 position in the 29th intron of the FBN1 gene, encoding the fibrillin-1 protein. This mutation was not observed in his parents but was detected in his two sons who manifested the physical features of MFS. Therefore, this mutation was considered to be a de novo mutation exhibiting a new pathogenic mechanism involving abnormal splicing. The presented case is unique in that the patient with MFS showed subcortical hemorrhage and had a novel de novo mutation in the FBN1 gene.

Marfan syndrome (MFS) is caused by mutations in the FBN1 (fibrillin-1) gene, but approximately 10% of MFS cases remain genetically unsolved. Here, we report a new FBN1 mutation in an MFS family that had remained negative after extensive molecular genomic DNA FBN1 testing, including denaturing high-performance liquid chromatography, Sanger sequencing, and multiplex ligation-dependent probe amplification. Linkage analysis in the family and cDNA sequencing of the proband revealed a deep intronic point mutation in intron 56 generating a new splice donor site. This mutation results in the integration of a 90-bp pseudo-exon between exons 56 and 57 containing a stop codon, causing nonsense-mediated mRNA decay. Although more than 90% of FBN1 mutations can be identified with regular molecular testing at the genomic level, deep intronic mutations will be missed and require cDNA sequencing or whole-genome sequencing.

Colobomata are etiologically heterogeneous and may occur as an isolated defect or as a feature of a variety of single-gene disorders, chromosomal syndromes, or malformation syndromes. Although not classically associated with Marfan syndrome, colobomata have been described in several reports of Marfan syndrome, typically involving the lens and rarely involving other ocular structures. While colobomata of the lens have been described in Marfan syndrome, there are very few reports of coloboma involving other ocular structures. We report a newborn boy presenting with coloboma of the iris, lens, retina, and optic disk who was subsequently diagnosed with Marfan syndrome. Marfan syndrome is a disorder of increased TGFβ signaling, and recent work in the mouse model suggests a role for TGFβ signaling in eye development and coloboma formation, suggesting a causal association between Marfan syndrome and coloboma.