Autosomal Recessive Infantile Hyaline Fibromatosis Identified Using Artificial Intelligence-Assisted Rapid Whole Genome Sequencing: A Rare, Multisystemic, Hereditary Disorder.

Infantile hyaline fibromatosis syndrome (HFS) is an ultra-rare genetic condition characterized by the deposition of hyaline material in the skin, muscle, and viscera. Potential complications include debilitating joint contractures, coarse facial features, recurrent infections, failure to thrive, and death. Here, we present the case of a six-month-old infant with a history of painful extremity contractures, global developmental delay, neck hemangioma, and feeding intolerance presenting to our institution with abdominal distension. The multi-systemic, rapidly progressing, severe nature of her symptoms prompted consultation with inpatient pediatric genetics. Per their recommendation, rapid whole-genome sequencing (rWGS) was done with Fabric GEM®-assisted artificial intelligence (Fabric Genomics, Oakland, California, United States) at Rady Children's Hospital Institute for Genomic Medicine (San Diego, California, United States), revealing homozygous pathogenic variant c.652T>C; P.Cys218Arg in the ANTXR2 gene consistent with HFS. This case was significant not only for its rarity, but also its early manifestation of symptoms, wide range of affected body systems, and severity of symptoms, which together present a fascinating diagnostic dilemma for future clinicians that should be taken into consideration. It also highlights the increasing utility of AI-assisted rWGS as a diagnostic tool for medically complex patients with unknown multisystemic hereditary conditions.

Beyond Skin Deep: A Case Report of Infantile Systemic Hyalinosis in a Six-Month-Old Infant.

A rare autosomal recessive condition called infantile systemic hyalinosis (ISH) is characterized by early-onset skin lesions that progress to the formation of numerous contractures. The underlying disease is the progressive accumulation of hyaline substances in many tissues. We are presenting the case of a male infant who was referred for evaluation and management at the age of six months. The infant had a history of recurrent episodes of diarrhea and showed limited movement in all four limbs. Upon physical examination, hyperpigmented papulonodular lesions on bony prominences and perianal regions were found, coupled with contractures in the elbow and knee joints. Hyaline deposition in the mid-dermal region was confirmed by histopathological analysis of a skin biopsy sample. The baby also had acute otitis media, which needed to be treated with antibiotics. Parents were counseled regarding the disease's diagnosis, complications, prognosis, and inheritance pattern. This case highlights the clinical presentation, diagnostic process, and management strategies employed in the care of ISH, emphasizing the importance of early recognition and multidisciplinary management in mitigating its devastating effects.

Hyaline fibromatosis syndrome: a rare, yet recognizable syndrome.

BACKGROUND: Hyaline fibromatosis syndrome is a rare autosomal recessive disorder caused by ANTXR2 pathogenic variants. The disorder is characterized by the deposition of amorphous hyaline material in connective tissues. The hallmarks of the disease are joint contractures, generalized skin stiffness, hyperpigmented papules over extensor surfaces of joints, fleshy perianal masses, severe diarrhea, and gingival hypertrophy. The severity of the disease varies and prognosis is poor. No specific treatment is yet available. Most patients with the severe form of the condition pass away before the second year of age. In this study, we describe the clinical and molecular findings of a cohort of seven hyaline fibromatosis syndrome patients who were diagnosed and followed up at a single tertiary reference center in Turkey. METHODS: Genomic DNA was extracted by standard salting out method from peripheric blood samples of three patients. In one patient DNA extraction was performed on pathology slides since peripheric blood DNA was not available. All coding exons of the ANTXR2 were amplified and sequenced on ABI Prism 3500 Genetic Analyser. RESULTS: Sanger sequencing was performed in 3 patients and homozygous c.945T>G p.(Cys315Trp), c.1073dup p.(Ala359CysfsTer13), and c.1074del p.(Ala359HisfsTer50) variants were identified in ANTXR2. All patients passed away before the age of five years. CONCLUSIONS: HFS is a rare, progressive disorder with a broad phenotypic spectrum. HFS can be recognized easily with distinctive clinical features. Nevertheless, it has poor prognosis with increased mortality due to severe clinical decompensation.

Investigating the Influence of ANTXR2 Gene Mutations on Protective Antigen Binding for Heightened Anthrax Resistance.

Bacillus anthracis is the bacterium responsible for causing the zoonotic disease called anthrax. The disease presents itself in different forms like gastrointestinal, inhalation, and cutaneous. Bacterial spores are tremendously adaptable, can persist for extended periods and occasionally endanger human health. The Anthrax Toxin Receptor-2 (ANTXR2) gene acts as membrane receptor and facilitates the entry of the anthrax toxin into host cells. Additionally, mutations in the ANTXR2 gene have been linked to various autoimmune diseases, including Hyaline Fibromatosis Syndrome (HFS), Ankylosing Spondylitis (AS), Juvenile Hyaline Fibromatosis (JHF), and Infantile Systemic Hyalinosis (ISH). This study delves into the genetic landscape of ANTXR2, aiming to comprehend its associations with diverse disorders, elucidate the impacts of its mutations, and pinpoint minimal non-pathogenic mutations capable of reducing the binding affinity of the ANTXR2 gene with the protective antigen. Recognizing the pivotal role of single-nucleotide polymorphisms (SNPs) in shaping genetic diversity, we conducted computational analyses to discern highly deleterious and tolerated non-synonymous SNPs (nsSNPs) in the ANTXR2 gene. The Mutpred2 server determined that the Arg465Trp alteration in the ANTXR2 gene leads to altered DNA binding (p = 0.22) with a probability of a deleterious mutation of 0.808; notably, among the identified deleterious SNPs, rs368288611 (Arg465Trp) stands out due to its significant impact on altering the DNA-binding ability of ANTXR2. We propose these SNPs as potential candidates for hypertension linked to the ANTXR2 gene, which is implicated in blood pressure regulation. Noteworthy among the tolerated substitutions is rs200536829 (Ala33Ser), recognized as less pathogenic; this highlights its potential as a valuable biomarker, potentially reducing side effects on the host while also reducing binding with the protective antigen protein. Investigating these SNPs holds the potential to correlate with several autoimmune disorders and mitigate the impact of anthrax disease in humans.

Hyaline Fibromatosis Syndrome Diagnosed by Whole Genome Sequencing.

Hyaline fibromatosis syndrome is an extremely rare autosomal recessive condition caused by biallelic pathogenic variants in the ANTXR2 gene that leads to abnormal growth of hyalinized fibrous tissue. Severity ranges from life-threatening intractable diarrhea, recurrent infection, and acute pain to milder disease resulting in skin lesions and less severe contractures. Here, we report the case of a 3-month-old female who presented with joint contractures and severe pain followed by failure to thrive. Diagnosis via ultra-rapid whole genome sequencing allowed our team to provide appropriate care and anticipatory guidance for this patient and family.

Infantile Systemic Hyalinosis: A Case Report and Literature Review.

Infantile systemic hyalinosis (ISH) is a very rare disorder belonging to the heterozygous group of genetic fibromatosis. There is a diffuse deposition of hyaline material in the skin, gastrointestinal tract, muscle, lymph node, spleen, thyroid, and adrenal gland due to which it presents clinically with multiple subcutaneous skin nodules, gingival hypertrophy, osteopenia, joint contractures, failure to thrive, and diarrhea with protein-losing enteropathy, and is associated with recurrent infections. The disease is caused by mutations in ANTXR2 also known as the CMG2 gene, which encodes the transmembrane-extracellular matrix assembly. In this report, we describe a nine-month-old male diagnosed with ISH based on the clinical presentation of severe skin lesions, painful joint contractures, diarrhea, and failure to thrive. His diagnosis was confirmed by molecular DNA sequencing of the ANTXR2 gene. Consanguinity and molecular diagnosis will be helpful for early diagnosis and accurate management.

Infantile Systemic Hyalinosis Presenting as Pseudo-Paralysis in Infancy: Study of Six Cases.

Infantile systemic hyalinosis is a very rare fatal autosomal recessive genetic disorder with a mutation in capillary morphogenesis gene-2- CMG2 /Human anthrax toxin-2 ANTXR2 resulting in spindle cell proliferation, altered collagen metabolism along with extensive deposition of hyaline material in the skin and several tissues. To date only a few cases have been reported in the literature, hence we reported this series. This study is a retrospective chart review of infants diagnosed with infantile systemic hyalinosis from January 2015 through December 2020 at a tertiary care children's hospital in South India. The mean age of presentation was 9.4 months, with a male to female ratio of 1:5. All children were born of consanguineous marriage except one child. All children had symptoms at birth, painful limb movements, multiple joint stiffness, gingival thickening, skin lesions around perianal, perioral areas, and frog-like position. Three (50%) children had stiff skin. Routine tests including complete blood count, liver function test, renal function test, creatine phosphokinase, nerve conduction studies, and metabolic tests were normal in all children. Skin biopsy showed hyalinized collagenous tissue in the dermis. Genetic study results of two cases revealed pathogenic variants in ANTXR2 gene. Infantile systemic hyalinosis should be considered in infants presenting with painful limb movements. The diagnosis helped in avoiding unnecessary investigations and prognostications. The genetic information from proband mutation helped in prenatal diagnosis in two families.

PCGEM1 promotes cell proliferation and migration in endometriosis by targeting miR-124-3p-mediated ANTXR2 expression.

BACKGROUND: Endometriosis, a common gynaecological disease in women, affects 10% of women of childbearing age. Among infertile women, this proportion is as high as 30-50%. Despite the high prevalence of endometriosis, the pathogenesis of endometriosis is still unclear. METHODS: In the present study, bioinformatics analysis and molecular and animal experiments were employed to explore the functions of PCGEM1 in the pathogenesis of endometriosis. We established an endometriosis rat model and isolated endometrial stromal cells (ESCs) and primary normal ESCs (NESCs). Bioinformatics analysis was adopted to study the roles of PCGEM1 in promoting the pathogenesis of endometriosis. Luciferase reporter assays and RNA pull-down assays were carried out to study the mechanism by which PCGEM1 regulates ANTXR2. RESULTS: Our results indicated that PCGEM1 promoted the motility and proliferation of ectopic endometrial cells, and the underlying mechanism was due to the direct binding of PCGEM1 to miR-124-3p to modulate ANTXR2 expression. CONCLUSION: PCGEM1 can influence endometrial stromal cell proliferation and motility and may be a novel therapeutic target for endometriosis.

Endothelial anthrax toxin receptor 2 plays a protective role in liver fibrosis.

Hepatocellular carcinoma is one of the leading cancers worldwide and is a potential consequence of fibrosis. Therefore, the identification of key cellular and molecular mechanisms involved in liver fibrosis is an important goal for the development of new strategies to control liver-related diseases. Here, single-cell RNA sequencing data (GSE136103 and GES181483) of clinical liver non-parenchymal cells were analyzed to identify cellular and molecular mechanisms of liver fibrosis. The proportion of endothelial subpopulations in cirrhotic livers was significantly higher than that in healthy livers. Gene ontology and gene set enrichment analysis of differentially expressed genes in the endothelial subgroups revealed that extracellular matrix (ECM)-related pathways were significantly enriched. Since anthrax toxin receptor 2 (ANTXR2) interacts with the ECM, the expression of ANTXR2 in the liver endothelium was analyzed. ANTXR2 expression in the liver endothelium of wild-type (WT) mice significantly decreased after a 4-time sequential injection of carbon tetrachloride (CCl4) to induce liver fibrosis. Next, conditional knockout mice selectively lacking Antxr2 in endothelial cells were generated. After endothelial-specific Antxr2 knockout mice were subjected to the CCl4 model, the degree of liver fibrosis in the knockout group was significantly more severe than that in the control group. In addition, ANTXR2 in human umbilical vein endothelial cells promoted matrix metalloproteinase 2 (MMP2) activation to degrade the ECM in vitro. Finally, endothelial-specific overexpression of Antxr2 alleviated the development of liver fibrosis following adeno-associated virus treatment. Collectively, these results suggested that endothelial ANTXR2 plays a protective role in liver fibrosis. This function of ANTXR2 may be achieved by promoting MMP2 activation to degrade the ECM.

Hyaline fibromatosis syndrome with a novel 4.41-kb deletion in ANTXR2 gene: A case report and literature review.

BACKGROUND: Hyaline fibromatosis syndrome is a rare autosomal recessive disorder with ANTXR2 mutations characterised by the accumulation of hyaline substances in tissues. We present a case with the severe form-infantile systemic hyalinosis (ISH)-with long survival and review the literature. METHODS AND RESULTS: Trio-exome sequencing revealed compound heterozygous mutations, including a novel 4.41 kb deletion on 4q21.21 and the previously reported c.1294C > T mutation, in the ANTXR2 gene. He was diagnosed with ISH and treated symptomatically. After follow-ups until 4 years of age, his recurrent respiratory infections and diarrhoea improved after one severe diarrhoea attack treated with intravenous gamma globulin. He is now awaiting surgical excision of gingival hypertrophy and joint contractures. CONCLUSION: The novel gross deletion in ANTXR2 enriches the genetic mutation spectrum of hyaline fibromatosis syndrome. The manifestation of decreased foetal movement, acute-infection attack or intravenous gamma globulin treatment may be associated with hyaline fibromatosis syndrome. A review of 116 reported cases reveals that missense mutations in the vWA domain are associated with joint symptoms, respiratory tract infection and diarrhoea, while frameshift mutations are associated with facial deformities and speech delays. We have enriched the current knowledge of the clinical manifestations and genetic mutation spectrum of HFS.

Capillary morphogenesis gene 2 (CMG2) mediates growth factor-induced angiogenesis by regulating endothelial cell chemotaxis.

Anthrax protective antigen (PA) is a potent inhibitor of pathological angiogenesis with an unknown mechanism. In anthrax intoxication, PA interacts with capillary morphogenesis gene 2 (CMG2) and tumor endothelial marker 8 (TEM8). Here, we show that CMG2 mediates the antiangiogenic effects of PA and is required for growth-factor-induced chemotaxis. Using specific inhibitors of CMG2 and TEM8 interaction with natural ligand, as well as mice with the CMG2 or TEM8 transmembrane and intracellular domains disrupted, we demonstrate that inhibiting CMG2, but not TEM8 reduces growth-factor-induced angiogenesis in the cornea. Furthermore, the antiangiogenic effect of PA was abolished when the CMG2, but not the TEM8, gene was disrupted. Binding experiments demonstrated a broad ligand specificity for CMG2 among extracellular matrix (ECM) proteins. Ex vivo experiments demonstrated that CMG2 (but not TEM8) is required for PA activity in human dermal microvascular endothelial cell (HMVEC-d) network formation assays. Remarkably, blocking CMG2-ligand binding with PA or CRISPR knockout abolishes endothelial cell chemotaxis but not chemokinesis in microfluidic migration assays. These effects are phenocopied by Rho inhibition. Because CMG2 mediates the chemotactic response of endothelial cells to peptide growth factors in an ECM-dependent fashion, CMG2 is well-placed to integrate growth factor and ECM signals. Thus, CMG2 targeting is a novel way to inhibit angiogenesis.

Anthrax toxin receptor 2 is a potential therapeutic target for non-small cell lung carcinoma with MET exon 14 skipping mutations.

Although MET tyrosine kinase inhibitors (TKIs) are generally effective against non-small cell lung carcinoma (NSCLC) with MET exon 14 skipping mutations (METΔex14), resistance to MET TKIs can occur, indicating the need to develop other therapeutic options. We found that Hs-746 T cells, which harbor METΔex14 plus amplification, were able to survive and grow in the absence of MET signaling, exhibiting primary resistance to MET TKIs. We also found a moderately positive correlation between MET and anthrax toxin receptor 2 (ANTXR2) mRNA expression in NSCLC cell lines using data from the Cancer Dependency Map database. As expected, Hs-746 T cells were positive for ANTXR2 expression. We used an antibody-drug conjugate (ADC) analog in the form of an anti-ANTXR2 monoclonal antibody, H8R23, conjugated to DT3C recombinant protein which consists of diphtheria toxin (DT) lacking the receptor-binding domain but containing the C1, C2, and C3 domains of streptococcal protein G (3C). H8R23-DT3C conjugates, which function in vitro like an ADC, induced Hs-746 T cells to undergo apoptosis, resulting in decreased viability. These findings collectively suggest that an ADC targeting ANTXR2 could be effective for the treatment of METΔex14-positive NSCLC.

Juvenile hyaline fibromatosis: A clinicopathological study of five cases.

Juvenile hyaline fibromatosis (JHF) is an extremely rare autosomal recessive disease that typically presents in infancy or early childhood. Largely due to the rarity, JHF is still not widely recognized by clinicians and pathologists in China. It is not uncommonly to misdiagnose the disease as other types of disorders. In this study, we present our experience with five cases of JHF to enhance the recognition of this rare but distinctive entity. There were 4 males and 1 female, with age at presentation ranging from 5 to 44 years. All patients presented with multiple subcutaneous nodular lesions of varying size in various parts of the body since birth or early childhood. Three patients also had joint involvement. Pathologically, the lesions were poorly circumscribed, located mainly in the dermis and subcutis. All five cases were characterized by abundant homogeneous hyaline-like matrix that differs sharply from the adjacent connective tissue, which stained strongly with periodic acid-Schiff (PAS) and was diastase resistant. Embedded within the eosinophilic glassy matrix were cords or small clusters of plump spindled to epithelioid cells, frequently with clear cytoplasm. Familiarity with the characteristic features of JHF is not only important in avoiding misdiagnosis but also essential for clinical management and prognostic evaluation.

Infantile systemic hyalinosis: Variable grades of severity.

BACKGROUND: Infantile systemic hyalinosis (ISH) is an autosomal recessively inherited disorder. The classical natural history of the disease is characterised by hypotonia, multiple contractures, skin lesions, osteopenia, joint pain, bone fractures, persistent diarrhoea and growth deficiency. MATERIALS AND METHODS: Two children manifested the severe type of ISH underwent genotypic confirmation. In order to identify which other family members have inherited the disease. We included siblings and cousins in this study. The baseline tool to study other family subjects was based on the phenotypic characterisations of each child. RESULTS: . Two children with the severe type of ISH showed craniosynostosis (brachycephaly and scaphocephaly) associated with multiple contractures, progressive joint osteolysis ending up with multiple joint dislocations. The full exome sequencing was carried out, revealing a previously reported heterozygous nonsense mutation с.1294С>Т and a novel heterozygous non-synonymous substitution c. 58T>A in ANTRX2 gene. Three children (sibling and cousins) manifested variable clinical manifestations relevant to ISH. Specifically, asymptoamtic skin and skeletal abnormalities of hypoplastic clavicles and 'shepherd's crook' deformity and coxa vara. CONCLUSION: It is mandatory to perform extensive family pedigree search to detect asymptomatic clinical features in siblings and cousins in families with first degree related marriages. Interestingly, in the mild and the moderate types of ISH, we observed undescribed combination of asymptomatic skin and skeletal abnormalities. This is a comparative study between the severe and the mild/moderate types in a group of children from consanguineous families. Our current study extends the phenotypic characterisations of ISH.

Juvenile hyaline fibromatosis: a rare oral disease case report and literature review.

Juvenile hyaline fibromatosis (JHF) is a rare recessive autosomal hereditary disorder characterized by papulonodular skin, gingival hyperplasia, flexural joint contractures, and osteolytic bone lesions. Worldwide, less than 70 cases have been reported. JHF is thought to be a disorder of collagen metabolism which is caused by genomic sequence variations in the ANTXR2/CMG2 gene and is characterized by homogenous amorphous hyaline material and fibrous tissue. JHF is most commonly diagnosed in infants and in children less than 5 years. We report a 28-month-old child of a consanguineous marriage who presented with severe gingival hyperplasia, multiple facial nodules, posterior occipital tumors, joint contractures, and osteolytic bone lesions. His limbs and fingers cannot be straightened, with a posture of frog pose. The occlusal and incisal surfaces of the teeth were completely covered with the gingival overgrowth. The gingival hypertrophy and facial swellings were surgically removed, with pathological features of monomorphic spindled cell proliferation surrounded by an abundant amorphous hyaline matrix. The genome sequencing was performed that a homozygous nucleotide mutation of ANTXR2/CMG2 gene was found. We outline this particular patient's presentation, followed by a discussion highlighting the characteristics that change with the condition and the treatments of this disease. The treatment of JHF is generally symptomatic treatment and requires multidisciplinary care. Physical rehabilitation has been advocated for a lifetime.

Enhanced Collagen Deposition in the Duodenum of Patients with Hyaline Fibromatosis Syndrome and Protein Losing Enteropathy.

Hyaline fibromatosis syndrome (HFS), resulting from ANTXR2 mutations, is an ultra-rare disease that causes intestinal lymphangiectasia and protein-losing enteropathy (PLE). The mechanisms leading to the gastrointestinal phenotype in these patients are not well defined. We present two patients with congenital diarrhea, severe PLE and unique clinical features resulting from deleterious ANTXR2 mutations. Intestinal organoids were generated from one of the patients, along with CRISPR-Cas9 ANTXR2 knockout, and compared with organoids from two healthy controls. The ANTXR2-deficient organoids displayed normal growth and polarity, compared to controls. Using an anthrax-toxin assay we showed that the c.155C>T mutation causes loss-of-function of ANTXR2 protein. An intrinsic defect of monolayer formation in patient-derived or ANTXR2KO organoids was not apparent, suggesting normal epithelial function. However, electron microscopy and second harmonic generation imaging showed abnormal collagen deposition in duodenal samples of these patients. Specifically, collagen VI, which is known to bind ANTXR2, was highly expressed in the duodenum of these patients. In conclusion, despite resistance to anthrax-toxin, epithelial cell function, and specifically monolayer formation, is intact in patients with HFS. Nevertheless, loss of ANTXR2-mediated signaling leads to collagen VI accumulation in the duodenum and abnormal extracellular matrix composition, which likely plays a role in development of PLE.

Gingival Hypertrophy in a Child with Hyaline Fibromatosis Syndrome.

Hyaline fibromatosis syndrome (HFS) is a rare autosomal recessive genetic disorder characterized by accumulation of hyalinized fibrous tissue with cutaneous, mucosal, osteoarticular, and systemic involvement. The condition is caused by a mutation of ANTXR2 gene that results in a faulty synthesis of a transmembrane protein which leads up to excessive deposition of hyaline material in extracellular space. The first signs may be present at birth or appear during infancy, and joint stiffness is the first, most common, symptom. Other manifestations include joint contractures, hyperpigmented macules over bony prominences of the joints, and gingival hypertrophy. The symptom that raises suspicion of HFS is present later, along with subcutaneous growths. The progression of the disease includes enteropathy with extensive protein loss, chronic diarrhea and frequent infections. We present a case of a five-year-old girl with severe gingival hypertrophy that caused difficulties in eating and speaking. To the best of our knowledge, this is also the first patient in Croatia with a confirmed ANTXR2 gene mutation described in the literature.

Clinical aspects of Hyaline Fibromatosis Syndrome and identification of a novel mutation.

BACKGROUND: Hyaline fibromatosis syndrome is an autosomal recessive disease caused by mutations in ANTXR2 which leads to loss of function of the transmembrane protein anthrax toxin receptor 2. It is distinguished by characteristic skin lesions, gingival hyperplasia, joint and bone disease, and systemic involvement. METHODS: Based on the case of an 11-year-old female patient with typical features of hyaline fibromatosis syndrome and the underlying pathogenic compound heterozygote variants in ANTXR2 we discuss the genetic and clinical aspects of hyaline fibromatosis syndrome. RESULTS: The novel mutation in ANTXR2 (c.1223T>C, p.Leu408Pro variant) seems to allow for a protracted course of the disease. CONCLUSION: Our findings add to the phenotypic, genetic, and biochemical spectrum of hyaline fibromatosis syndrome.

Genetic, clinical and biochemical characterization of a large cohort of patients with hyaline fibromatosis syndrome.

BACKGROUND: Hyaline fibromatosis syndrome (HFS) is a rare clinical condition in which bi-allelic variants in ANTXR2 are associated with extracellular hyaline deposits. It manifests as multiple skin nodules, patchy hyperpigmentation, joint contractures and severe pain with movement. HFS shows some clinical overlap to Farber disease (FD), a recessive lysosomal storage disorder. RESULTS: We here present the largest cohort of independent, genetically confirmed HFS cases reported to date: in 19 unrelated index patients, we identified ten distinct homozygous ANTXR2 mutations, three of which are novel frame-shift variants. The associated clinical data are consistent with the previous hypothesis of non-truncating variants in the terminal exons 13-17 to confer rather mild phenotypes. The novel observation of gender-dependent disease manifestation in our cohort received support from a meta-analysis of all previously published cases. Untargeted blood-based metabolomics revealed patient samples to be biochemically distinct from control samples. Numerous potential HFS biomarker metabolites could thus be identified. We also found metabolomics profiles of HFS patients to highly overlap with those from FD patients. CONCLUSIONS: Our study extends the mutational spectrum for HFS, suggests gender-dependency of manifestation, and provides pilot metabolomics data for biomarker identification and a better pathomechanistic understanding of the disorder.