Oral-facial-digital Syndrome Type 1 Research Articles

Extraciliary OFD1 Is Involved in Melanocyte Survival through Cell Adhesion to ECM via Paxillin.

Primary cilia play a significant role in influencing cell fate, including apoptosis in multiple cell types. In the lesional epidermis of vitiligo patients, a reduced number of ciliated cells was observed. Our study also revealed a downregulation of oral-facial digital syndrome type 1 (OFD1) in the affected skin of vitiligo patients. However, it remains unknown whether primary cilia are involved in the control of melanocyte apoptosis. While both intraflagellar transport 88 (IFT88) and retinitis pigmentosa GTPase regulator-interacting protein-1 like (RPGRIP1L) are associated with ciliogenesis in melanocytes, only the knockdown of OFD1, but not IFT88 and RPGRIP1L, resulted in increased melanocyte apoptosis. OFD1 knockdown led to a decrease in the expression of proteins involved in cell-extracellular matrix (ECM) interactions, including paxillin. The OFD1 amino acid residues 601-1012 interacted with paxillin, while the amino acid residues 1-601 were associated with ciliogenesis, suggesting that the OFD1 domains responsible for paxillin binding are distinct from those involved in ciliogenesis. OFD1 knockdown, but not IFT88 knockdown, inhibited melanocyte adhesion to the ECM, a defect that was restored by paxillin overexpression. In summary, our findings indicate that the downregulation of OFD1 induces melanocyte apoptosis, independent of any impairment in ciliogenesis, by reducing melanocyte adhesion to the ECM via paxillin.

Pathological variant of OFD1 gene identified in a pedigree affected with oral-facial-digital syndrome type 1

To detect pathological variant in a Chinese pedigree affected with oral-facial-digital syndrome type 1 (OFD1). Whole-exome sequencing was used to scan the whole exome of the proband. Potential variant of the OFD1 gene was also detected in all members of the pedigree and 100 healthy controls by Sanger sequencing. X chromosome inactivation analysis was performed. With the determination of the genotype, prenatal diagnosis was carried out by amniotic fluid sampling. A c.1189_1192delAATC (p. Q398Lfs*2) variant was identified in the OFD1 gene of the proband, other patients from this pedigree, as well as the fetus. The same variant was not found among healthy members from this pedigree and the 100 healthy controls. X chromosome inactivation analysis identifies the pregnant woman and her younger sister both had a non-random inactivation, other women patients had a random inactivation. The c.1189_1192delAATC (p. Q398Lfs*2) variant of the OFD1 gene probably underlies the pathogenesis in this case. The new variant has enriched pathological spectrum of the OFD1 gene. The reason of intrafamilial clinical variability still need to be further confirmed.

Phenotypic overlap between cardioacrofacial dysplasia-2 and oral-facial-digital syndrome

Oral-facial digital (OFD) syndrome is characterized by abnormalities of the face (hypertelorism and low set-ears), oral cavity (multiple frenula, lingual hamartoma, or lobulated tongue) and extremities (postaxial polydactyly). At least 19 genes have been implicated in the development of OFD syndrome. Herein, we report the case a 13-year-old patient with atrioventricular septal defect, moderate intellectual disability, epilepsy, and features of OFD, including multiple oral frenula, and postaxial polydactyly of the hands and feet. The patient had a de novo heterozygous variant in PRKACB: chr1(GRCh37):g.84700915T > C, c.1124T > C (NM_182948.4), p.(Phe375Ser). To date, four patients with pathogenic monoallelic variants in PRKACB have been reported, and the condition associated with these variants is referred to as Cardioacrofacial dysplasia-2 (CAFD2, MIM619143). Previously reported features of this condition include congenital heart disease (e.g., atrioventricular septal defect) and postaxial polydactyly, and two of the patients had multiple oral frenula. We suggest that a significant phenotypic overlap exists between CAFD2 and OFD syndrome, in that these patients especially share the features of postaxial polydactyly and multiple oral frenula. The phenotypic similarity between patients with CAFD2 and classic OFD syndrome with an OFD1 variant might be explained by the recent in vitro experimental finding that a protein kinase A subunit encoded by PRKACB directly phosphorylates the OFD1 protein. From the standpoint of genetic counseling, OFD syndrome type1, the prototypic form of OFD, exhibits an X-linked dominant inheritance pattern, whereas other forms of OFD syndrome exhibit an autosomal recessive inheritance pattern. Recognition of CAFD2 as a differential diagnosis or forme fruste of OFD syndrome suggests that an autosomal dominant pattern of inheritance should also be considered during genetic counseling.

Oral-Facial-Digital Syndrome Type 1: Further Clinical and Molecular Delineation in 2 New Families.

Oral-facial-digital syndrome type 1 (OFD1) [OMIM 311200] is a rare genetic disorder associated with congenital anomalies of the oral cavity, face, and digits. This condition is associated with mutations in the OFD1 gene. Our objective was to recruit patients with the OFD1 clinical phenotype without genetic confirmation, aiming to identify genetic variants in the OFD1 gene. Three patients from 2 unrelated families were recruited into our study. We employed a variety of genomic techniques on these patients, including candidate gene analysis, array comparative genomic hybridization, whole-exome sequencing, and whole-genome sequencing. We investigated 3 affected patients from 2 unrelated families with a clinical diagnosis of OFD1. We discovered a novel pathogenic dominant missense mutation c.635G>C (p.Arg212Pro) in the OFD1 gene in one family. A novel frameshift, loss-of-function mutation c.306delA (p.Glu103LysfsTer42) was detected in the affected patient in the second family. These new genetic variants will add to the spectrum of known OFD1 mutations associated with the OFD1 disorder. Our study also confirms the variable phenotypic presentation of OFD1 and its well-recognized association with central nervous system malformations and renal anomalies. Molecular diagnostic confirmation achieved in these families will have positive implications for their medical management.

Clinical spectrum of male patients with OFD1 mutations

Oral-facial-digital syndrome type 1 (OFD1) is a ciliopathy characterized by oral, facial, and digital malformations that are often accompanied by polycystic lesion of the kidney and central nervous involvement. OFD1 shows an X-linked recessive inheritance caused by mutation in the OFD1 gene (Xp22.2). The disease is generally considered embryonic lethal for hemizygous males. However, males with OFD1 mutations were recently reported. Here, we report four additional Japanese male patients with OFD1 variants and describe the variable clinical manifestation and disease severity among the four patients. Patient 1 with pathogenic indels including a 19-bp deletion and 4-bp insertion (c.2600-18_2600delinsACCT) had end-stage renal disease (ESRD) with bilateral cystic kidneys and sensory hearing loss. He showed neither intellectual disability nor facial or digital dysmorphism. Patient 2 with a missense variant in exon 7 (c.539 A > T, p.Asp180Val) presented head circumference enlargement, brachydactyly, high-arched palate, micropenis, severe global developmental delay, and ESRD. Patient 3 had a single base substitution at the splice donor site of intron 16 (c.2260 + 2 T > G) causing a 513-bp deletion at the transcript level. The patient had chronic kidney disease and speech delay, but no oral, facial, or digital dysmorphism. His uncle (patient 4) carried the same OFD1 variant and showed ESRD with extra-renal malformations including obesity and micropenis, which was previously diagnosed as Bardet-Biedl syndrome. The OFD1 mutations were not lethal in these four male patients, likely because the three mutations were in-frame or missense. This report provided insights into the onset mechanism and phenotype-genotype association in patients with OFD1 mutations.

An Atypical Presentation of a Male with Oral-Facial-Digital Syndrome Type 1 Related Ciliopathy.

Background. Oral-facial-digital syndrome type 1 (OFD1) is a rare condition with X-linked dominant inheritance caused by mutations in the Cxorf5 (OFD1) gene. This gene encodes the OFD1 protein located within centrosomes and basal bodies of primary cilia. Approximately 15–50% of patients with OFD1 progress to end-stage kidney disease following development of polycystic changes within the kidneys. This condition almost always causes intrauterine lethality in males. Description of Case Diagnosis and Treatment. A Caucasian male aged 9 years and 9 months presented with increased urinary frequency, increased thirst, and decreased appetite. Physical examination demonstrated short stature, hearing loss, photophobia, murmur, and hypogonadism. He had no other dysmorphic features. Laboratory results revealed anemia, renal insufficiency, and dilute urine with microscopic hematuria but no proteinuria. Ultrasound showed small kidneys with increased echogenicity but no evidence of cystic changes. A Ciliopathy Panel showed a novel and likely pathogenic deletion, approximately 7.9 kb, in the OFD1 gene encompassing exons 16, 17, and 19 (c.1654+833_2599+423del). Brain MRI did not demonstrate typical OFD1 findings. He is currently on chronic hemodialysis awaiting transplant from a living donor. Conclusions. We present a male patient with OFD1 mutation who lacks the classic OFD1 phenotype who presented with end-stage renal disease without evidence of polycystic changes within the kidneys.

OFD1 and flotillins are integral components of a ciliary signaling protein complex organized by polycystins in renal epithelia and odontoblasts.

Mutation of the X-linked oral-facial-digital syndrome type 1 (OFD1) gene is embryonic lethal in males and results in craniofacial malformations and adult onset polycystic kidney disease in females. While the OFD1 protein localizes to centriolar satellites, centrosomes and basal bodies, its cellular function and how it relates to cystic kidney disease is largely unknown. Here, we demonstrate that OFD1 is assembled into a protein complex that is localized to the primary cilium and contains the epidermal growth factor receptor (EGFR) and domain organizing flotillin proteins. This protein complex, which has similarity to a basolateral adhesion domain formed during cell polarization, also contains the polycystin proteins that when mutant cause autosomal dominant polycystic kidney disease (ADPKD). Importantly, in human ADPKD cells where mutant polycystin-1 fails to localize to cilia, there is a concomitant loss of localization of polycystin-2, OFD1, EGFR and flotillin-1 to cilia. Together, these data suggest that polycystins are necessary for assembly of a novel flotillin-containing ciliary signaling complex and provide a molecular rationale for the common renal pathologies caused by OFD1 and PKD mutations.

Nevus Comedonicus in Oral‐Facial‐Digital Syndrome Type 1: A New Finding or Overlapping Syndromes?

We report a patient with oral-facial-digital syndrome type 1 (OFDS1) who exhibited features overlapping those of nevus comedonicus syndrome, an unusual presentation that may potentially represent a new variant of OFDS1. OFDS1 and nevus comedonicus syndrome represent two rare syndromes with numerous overlapping features that have yet to be described in relation to one another. The features present in our patient led us to propose the possibility of a new variant of OFDS1 in which nevus comedonicus represents a cutaneous manifestation of the syndrome. Knowledge of this potential relationship is important for identification and management of the syndromes' accompanying manifestations in affected patients and may offer further insight into crossroads of pathogenesis.

Expanding the molecular basis and phenotypic spectrum of X-linked Joubert syndrome associated with OFD1 mutations

Using a combination of linkage mapping and massively parallel sequencing of the X-chromosome exome, we identified an 18-bp deletion in exon 8 of the oral-facial-digital syndrome type 1 (OFD1) gene in a family with X-linked Joubert syndrome (JBTS10). The deletion results in an in-frame deletion of six amino acids. New features not noted in the two previously reported cases of X-linked Joubert syndrome include the presence of polycystic kidney disease, polymicrogyria and hydrocephalus. Our study further underlines the power of genetic mapping combined with massively parallel sequencing as a powerful tool for novel disease gene and mutation discovery.

A novel mutation in the OFD1 (Cxorf5) gene may contribute to oral phenotype in patients with oral‐facial‐digital syndrome type 1

Oral-facial-digital syndrome (OFDS) type 1 (OFD1) is an X-linked dominant condition associated with embryonic male lethality. It almost always affects the oral cavity, face, and digits. It is considered to be a ciliopathy caused by mutations in the OFD1 gene. A variety of mutations have been described, and a genotype-phenotype correlation has been suggested. The proband was an 8-year-old Spanish girl with suspected OFD1. We extended the pedigree to three proband's generations, performing a thorough physical examination and screening for OFD1 mutations in nine individuals. The proband, her mother, and her sister showed oral findings consistent with OFD1. Ultrasound evaluation revealed the existence of renal cysts only in the proband's mother. The rest of the family (all male) had no relevant morphological abnormalities. A single-base deletion in exon 16 of OFD1 (c.2183delG) leading to a frameshift was detected in the proband, her mother, and her sister. Because all three women had a similar oral phenotype, this new mutation might be involved in the development of the OFD1 oral manifestations. In cases of OFDS, physical examination (including the oral cavity and renal function) and genetic screening of the probands and their relatives are mandatory.

OFD1, the Gene Mutated in Oral-Facial-Digital Syndrome Type 1, Is Expressed in the Metanephros and in Human Embryonic Renal Mesenchymal Cells

Oral-facial-digital syndrome type 1 (OFD1) causes polycystic kidney disease (PKD) and malformations of the mouth, face and digits. Recently, a gene on Xp22, OFD1, was reported to be mutated in a limited set of OFD1 patients. This study describes mutation analysis in six further OFD1 families. Additionally, gene expression was sought in human development. In two OFD1 kindreds affected by PKD, a frameshift mutation and a splice-site mutation were detected. In four apparently sporadic cases, three frameshift and a missense mutation were found. Using RT-PCR of RNA from first-trimester normal human embryos, both alternative splice forms of mRNA (OFD1a and OFD1b) were found to be widely expressed in organogenesis. Northern blot detected OFD1 mRNA in metanephros, brain, tongue, and limb, all organs affected in the syndrome. A polyclonal antibody directed to a C-terminal OFD1a epitope detected a 120-kD protein in the metanephros and in human renal mesenchymal cell lines. In normal human embryos, OFD1a immunolocalized to the metanephric mesenchyme, oral mucosa, nasal and cranial cartilage, and brain. Moreover, using normal human renal mesenchymal cell lines, the immunoreactive protein colocalized with gamma-tubulin, suggesting that OFD1 is associated with the centrosome. First, it is concluded that OFD1 mutations would generally be predicted to result in unstable transcripts or nonfunctional proteins. Second, OFD1 is expressed in human organogenesis; on the basis of the metanephric expression pattern, the results suggest that OFD1 plays a role in differentiation of metanephric precursor cells.

The oral-facial-digital syndrome type 1 (OFD1), a cause of polycystic kidney disease and associated malformations, maps to Xp22.2-Xp22.3

Key features of the oral-facial-digital syndrome type 1 (OFD1) include malformations of the face, oral cavity and digits. In addition, the clinical phenotype often includes mental retardation and renal functional impairment. Approximately 75% of cases of OFD1 are sporadic, and the condition occurs almost exclusively in females. In familial cases, the most likely mode of inheritance is considered to be X-linked dominant with prenatal lethality in affected males. Therefore, the OFD1 gene product appears to have widespread importance in organogenesis and is essential for fetal survival. We have studied two kindreds in which the clinical course was dominated by polycystic kidney disease requiring dialysis and transplantation. Using polymorphic chromosome markers spaced at approximately 10 cM intervals along the X chromosome, we mapped the disease to a region on the short arm of the X chromosome (Xp22.2-Xp22.3) spanning 19.8 cM and flanked by crossovers with the markers DXS996 and DX7S105. There was a maximum lod score of 3.32 in an 'affecteds only' analysis using a marker within the KAL gene (theta = 0.0 ), thereby confirming the location of the gene for OFD1 on the X chromosome. The remainder of the X chromosome was excluded by recombinants in affected individuals. The importance of our findings includes the definitive assignment of this male-lethal disease to the X chromosome and the mapping of a further locus for a human polycystic kidney disease. Furthermore, this mapping study suggests a possible mouse model for OFD1 as the X-linked dominant Xpl mutant, in which polydactyly and renal cystic disease occurs, maps to the homologous region of the mouse X chromosome.

Oral-facial-digital syndrome type 1 is another dominant polycystic kidney disease: clinical, radiological and histopathological features of a new kindred.

Oral-facial-digital syndrome type 1 (OFD1) is a rare disorder comprising malformations of the face, oral cavity, hands, and feet. Polycystic kidney disease (PKD) is a more recently recognized feature of the syndrome. We now report on the clinical, radiological and histopathological features of an OFD1 and PKD kindred with five affected members in three subsequent generations. All patients were female and had accompanying PKD as assessed by ultrasound scans. The plasma creatinine was normal in three, but PKD caused end-stage renal failure in two of these individuals in the second and fifth decades. A histochemical analysis of renal tissue from one affected member of this kindred demonstrated a predominantly glomerulocystic kidney disease with a minor population of cysts derived from distal tubules as assessed by staining with Arachis hypogaea lectin. Cyst epithelia had a high level of mitosis as assessed by staining with antisera to proliferating cell nuclear antigen, and distal cysts overexpressed PAX2 protein, a potentially oncogenic transcription factor. We detected multiple pancreatic cysts in one member affected by OFD1 although there were no symptoms of pancreatic disease; this constitutes a novel radiological feature of the syndrome. This kindred illustrates the inheritance pattern of OFD1 and its accompanying PKD. Although the renal disease superficially resembles ADPKD with macroscopic cysts and a dominant inheritance pattern, histology shows a predominance of glomerular cysts and the syndrome is X-linked, with affected males dying before birth. The recognition of the accompanying dysmorphic features is the key to a diagnosis of OFD1 in a female child or adult who presents with PKD.