Cardiofaciocutaneous syndrome - a longitudinal study of a case over 33 years: case report and review of the literature

Exploring the clinical complexity of cardio-facio-cutaneous syndrome: insights from a pediatric case series

Background

Cardio-Facio-Cutaneous syndrome (CFCS) is a rare autosomal dominant genetic disorder primarily caused by BRAF gene mutations, posing diagnostic challenges due to its multifaceted clinical presentation.

Objective

To elucidate the clinical characteristics of pediatric CFCS patients, expanding the phenotypic spectrum to enhance early diagnostic capabilities, while also presenting the relationship between genotye and corresponding phenotype severity.

Methods

From January 2015 to March 2022, four children diagnosed with CFCS in Children's Hospital of Chongqing Medical University were included for analysis. Whole exome sequencing (WES) was conducted to identify the types and locations of possible gene mutations. Neurological development was assessed using electroencephalography (EEG), magnetic resonance imaging (MRI) and Gesell developmental evaluation.

Results

All four CFCS patients exhibited de novo BRAF gene mutations, manifesting with cardiac malformations, distinctive facial features, skin and hair changes, and neurological abnormalities. WES revealed that the specific BRAF mutations were closely linked to their clinical severity. Three patients displayed milder symptoms (case 1-3, genotype I or II), demonstrating stability or slight improvement, whereas one patient (case 4, genotype III) suffered from a severe phenotype characterized by profound neurological and digestive system impairments, leading to a significantly reduced quality of life and a grim prognosis.

Conclusion

In CFCS patients, severe developmental delay and seizures are predominant neurological features, possibly accompanied by continuous spike-and-wave during sleep (CSWS) and severe sleep disturbances. CFCS generally carries a poor prognosis, underscoring the importance of disease awareness and early genetic testing.

The Cardiofaciocutaneous Syndrome: From Genetics to Prognostic-Therapeutic Implications

Cardiofaciocutaneous (CFC) syndrome is one of the rarest RASopathies characterized by multiple congenital ectodermal, cardiac and craniofacial abnormalities with a mild to severe ocular, gastrointestinal and neurological involvement. It is an autosomal dominant syndrome, with complete penetrance, caused by heterozygous pathogenic variants in the genes BRAF, MAP2K1/MEK1, MAP2K2/MEK2, KRAS or, rarely, YWHAZ, all part of the RAS-MAPK pathway. This pathway is a signal transduction cascade that plays a crucial role in normal cellular processes such as cell growth, proliferation, differentiation, survival, metabolism and migration. CFC syndrome overlaps with Noonan syndrome, Costello syndrome, neurofibromatosis type 1 and Legius syndrome, therefore making the diagnosis challenging. Neurological involvement in CFC is more severe than in other RASopathies. Phenotypic variability in CFC patients is related to the specific gene affected, without a recognized genotype-phenotype correlation for distinct pathogenic variants. Currently, there is no specific treatment for CFC syndrome. Encouraging zebrafish model system studies suggested that, in the future, MEK inhibitors could be a suitable treatment of progressive phenotypes of CFC in children. A multidisciplinary care is necessary for appropriate medical management.

A Case Report of Cardiofaciocutaneous Syndrome with MAP2K1 Pathogenic Variant

Craniofacial dysmorphism, cardiac abnormalities, ectodermal abnormalities, psychomotor delay, intellectual disability, and short stature are all hallmarks of the extremely rare disorder known as cardiofaciocutaneous syndrome (CFCS). Although CFCS is considered rare, approximately 300 cases have been documented in the literature. In this report, we discuss a patient diagnosed with CFCS without the typical heart malformations but with craniofacial features, skin abnormalities, intellectual disability, and short stature. Genetic testing revealed the presence of three potentially harmful variants: one in the MAP2K1 gene and two in the ATP2B3 and CDC42BPB genes, the significance of which is currently not yet found. Our findings in this case report suggest that the clinical symptoms of CFCS may be atypical, thereby expanding our understanding of the symptom spectrum of the disease. Simultaneously, the link between the clinical symptoms of the patient and the two unknown pathogenic variants has not been established. This case report supplements existing clinical reference material by providing valuable insights into the specific scenario.

Exome sequencing in a child with neurodevelopmental disorder and epilepsy: Variant analysis of the AHNAK2 gene

Background

The AHNAK2 gene encodes a large nucleoprotein expressed in several tissues, including brain, squamous epithelia, smooth muscle, and neuropil. Its role in calcium signaling has been suggested and to date, clear evidence about its involvement in the pathogenesis of clinical disorders is still lacking.

Methods

Here, we report a female 24‐year‐old patient diagnosed with a cardio‐facio‐cutaneous‐like phenotype (CFC‐like), characterized by epilepsy, psychomotor development delay, atopic dermatitis, congenital heart disease, hypotonia, and facial dysmorphism, who is compound heterozygote for two missense mutations in the AHNAK2 gene detected by exome sequencing.

Results

This patient had no detectable variant in any of the genes known to be associated with the cardio‐facio‐cutaneous syndrome. Moreover, the mode of inheritance does not appear to be autosomal dominant, as it is in typical CFC syndrome. We have performed in silico assessment of mutation severity separately for each missense mutation, but this analysis excludes a severe effect on protein function. Protein structure predictions indicate the mutations are located in flexible regions possibly involved in molecular interactions.

Conclusion

We discuss an alternative interpretation on the potential involvement of the two missense mutations in the AHNAK2 gene on the expression of CFC‐like phenotype in this patient based on inter‐allelic complementation.