Renal insufficiency, a frequent complication with age in oral-facial-digital syndrome type I

Oncogenic FGFR Fusions Produce Centrosome and Cilia Defects by Ectopic Signaling

A single primary cilium projects from most vertebrate cells to guide cell fate decisions. A growing list of signaling molecules is found to function through cilia and control ciliogenesis, including the fibroblast growth factor receptors (FGFR). Aberrant FGFR activity produces abnormal cilia with deregulated signaling, which contributes to pathogenesis of the FGFR-mediated genetic disorders. FGFR lesions are also found in cancer, raising a possibility of cilia involvement in the neoplastic transformation and tumor progression. Here, we focus on FGFR gene fusions, and discuss the possible mechanisms by which they function as oncogenic drivers. We show that a substantial portion of the FGFR fusion partners are proteins associated with the centrosome cycle, including organization of the mitotic spindle and ciliogenesis. The functions of centrosome proteins are often lost with the gene fusion, leading to haploinsufficiency that induces cilia loss and deregulated cell division. We speculate that this complements the ectopic FGFR activity and drives the FGFR fusion cancers.

Regulation of autophagosome biogenesis by OFD1-mediated selective autophagy

Autophagy is a lysosome-dependent degradation pathway essential to maintain cellular homeostasis. Therefore, either defective or excessive autophagy may be detrimental for cells and tissues. The past decade was characterized by significant advances in molecular dissection of stimulatory autophagy inputs; however, our understanding of the mechanisms that restrain autophagy is far from complete. Here, we describe a negative feedback mechanism that limits autophagosome biogenesis based on the selective autophagy-mediated degradation of ATG13, a component of the ULK1 autophagy initiation complex. We demonstrate that the centrosomal protein OFD1 acts as bona fide autophagy receptor for ATG13 via direct interaction with the Atg8/LC3/GABARAP family of proteins. We also show that patients with Oral-Facial-Digital type I syndrome, caused by mutations in the OFD1 gene, display excessive autophagy and that genetic inhibition of autophagy in a mouse model of the disease, significantly ameliorates polycystic kidney, a clinical manifestation of the disorder. Collectively, our data report the discovery of an autophagy self-regulated mechanism and implicate dysregulated autophagy in the pathogenesis of renal cystic disease in mammals.

Molecular diagnosis of kidney transplant failure based on urine

In light of the organ shortage, there is a great responsibility to assess postmortal organs for which procurement has been consented and to increase the life span of transplanted organs. The former responsibility has moved many centers to accept extended criteria organs. The latter responsibility requires an exact diagnosis and, if possible, omission of the harmful influence on the transplant. We report the course of a kidney transplant that showed a steady decline of function over a decade, displaying numerous cysts of different sizes. Clinical workup excluded the most frequent causes of chronic transplant failure. The filed allocation documents mentioned the donor's disease of oral-facial-digital syndrome, a rare ciliopathy, which can also affect the kidney. Molecular diagnosis was performed by culturing donor tubular cells from the recipient´s urine more than 10 years after transplantation. Next-generation panel sequencing with DNA from tubular urinary cells revealed a novel truncating mutation in OFD1, which sufficiently explains the features of the kidney transplants, also found in the second kidney allograft. Despite this severe donor disease, lifesaving transplantation with good long-term outcome was enabled for 5 recipients.

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

OBJECTIVE

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.

DESIGN

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.

RESULTS

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.

CONCLUSIONS

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.

OFD1 mutation induced renal failure and polycystic kidney disease in a pair of childhood male twins in China

BACKGROUND

Oral-facial-digital syndrome type 1 (OFD1) is a rare ciliopathy mainly with an X-linked dominant pattern of inheritance, which is caused by mutations in the OFD1 gene. The OFD1 protein is located within the centrosomes and basal bodies of the primary cilia. It is reported that approximately 15%–50% cases of OFD1 progress to end-stage renal disease (ESRD) following development of polycystic kidney diseases (PKD). Here we report a pair of childhood male twins who presented only renal failure and PKD caused by an OFD1 mutation in China.

CASE SUMMARY

A pair of 14-year male twins were hospitalized with a complaint of abnormal renal function for nine days. They both complained of ankle pain for 3 mo vs 2 wk, respectively. They denied fever, abdominal pain, daytime or nighttime enuresis, urgency, dysuria, or gross hematuria. Laboratory tests at a local hospital showed renal failure (serum creatinine 485 μmol/L vs 442 μmol/L, blood urea nitrogen 14.7 mol/L vs 14.5 mol/L) and anemia (hemoglobin 88 g/L vs 98 g/L). The twins are monozygotic. There was no abnormal birth, past medical, or family history. Clinical data were analyzed and genetic analysis on PKD was carried out in the twins by next-generation sequencing. The results showed that the twins presented low-molecular-weight proteinuria, hyposthenuria, anemia, renal failure, and renal polycystic changes. Genetic tests showed that the twins both carried a hemizygous mutation in exon 19 c.2524G>A (p. G842R) of the OFD1 gene. Their mother heterozygously carried the same mutation as the twins but was without any phenotypes while their father was normal.

CONCLUSION

We have reported a pair of childhood male twins with an OFD1 mutation who presented ESRD and PKD but without any other phenotypes of OFD1 in China.

An Orofaciodigital Syndrome 1 Patient and Her Mother Carry the Same OFD1 Mutation but Have Different X Chromosome Inactivation Patterns

Orofaciodigital syndrome 1 (OFD-1) is a rare, X-linked, dominantly inherited disorder caused by an OFD1 mutation that can cause polycystic kidneys. A 37-year-old woman on hemodialysis therapy was admitted to our hospital for trans-catheter arterial embolization therapy for enlarged polycystic kidneys. Lobulated tongue and brachydactyly were noticed, prompting an OFD1 sequencing analysis. Sequencing revealed a causal four-base-pair deletion in exon 13, both in the patient and in her mother, whose renal function had been retained. The peripheral leukocyte X chromosome inactivation pattern was skewed in the patient but not in her mother, suggesting some role in their phenotypic difference.

Clinical characteristics of individual organ system disease in non-motile ciliopathies

Non-motile ciliopathies (disorders of the primary cilia) include autosomal dominant and recessive polycystic kidney diseases, nephronophthisis, as well as multisystem disorders Joubert, Bardet-Biedl, Alström, Meckel-Gruber, oral-facial-digital syndromes, and Jeune chondrodysplasia and other skeletal ciliopathies. Chronic progressive disease of the kidneys, liver, and retina are common features in non-motile ciliopathies. Some ciliopathies also manifest neurological, skeletal, olfactory and auditory defects. Obesity and type 2 diabetes mellitus are characteristic features of Bardet-Biedl and Alström syndromes. Overlapping clinical features and molecular heterogeneity of these ciliopathies render their diagnoses challenging. In this review, we describe the clinical characteristics of individual organ disease for each ciliopathy and provide natural history data on kidney, liver, retinal disease progression and central nervous system function.

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.

Successful treatment of facial milia in an infant with orofaciodigital syndrome type 1

We report the successful treatment of multiple facial milia with manual extraction and tretinoin in a child with orofaciodigital syndrome type 1. Treatment with topical medications may be insufficient in individuals with orofaciodigital syndrome type 1, and pitted scarring is often a sequala. This case demonstrates that manual extraction is well tolerated and effective in the treatment of multiple milia. In addition, clinicians need to be aware of this rare genetic condition, which commonly presents de novo and can lead to significant morbidity if untreated.

The centrosomal OFD1 protein interacts with the translation machinery and regulates the synthesis of specific targets

Protein synthesis is traditionally associated with specific cytoplasmic compartments. We now show that OFD1, a centrosomal/basal body protein, interacts with components of the Preinitiation complex of translation (PIC) and of the eukaryotic Initiation Factor (eIF)4F complex and modulates the translation of specific mRNA targets in the kidney. We demonstrate that OFD1 cooperates with the mRNA binding protein Bicc1 to functionally control the protein synthesis machinery at the centrosome where also the PIC and eIF4F components were shown to localize in mammalian cells. Interestingly, Ofd1 and Bicc1 are both involved in renal cystogenesis and selected targets were shown to accumulate in two models of inherited renal cystic disease. Our results suggest a possible role for the centrosome as a specialized station to modulate translation for specific functions of the nearby ciliary structures and may provide functional clues for the understanding of renal cystic disease.

An Atypical Presentation of a Male with Oral-Facial-Digital Syndrome Type 1 Related Ciliopathy. Case Rep Nephrol. 2016;2016:3181676. [PMID: 27651963 PMCID: PMC5019883 DOI: 10.1155/2016/3181676]

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.

Daughter and mother with orofaciodigital syndrome type 1 and glomerulocystic kidney disease

A 35-year-old woman was admitted to our hospital for evaluation of end-stage renal failure. Diagnostic imaging, including ultrasonography and magnetic resonance imaging, showed polycystic kidneys and peribiliary hepatic cysts, but the renal cysts were isointense and her kidneys were smaller than the end-stage kidneys of patients with autosomal dominant polycystic kidney disease. Glomerulocystic kidney disease was diagnosed by renal biopsy. Clinical examination revealed findings such as a missing maxillary canine, lingual anomalies, and brachydactyly. Genetic testing gave a diagnosis of orofaciodigital syndrome type 1 with a 5 nucleotide deletion indicating a frameshift mutation in exon 9. The patient's mother had the same mutation and similar clinical findings. This case is useful for understanding kidney and liver involvement in orofaciodigital syndrome type 1.

Ccdc11 is a novel centriolar satellite protein essential for ciliogenesis and establishment of left-right asymmetry

Mutations in CCDC11 cause aberrant placement of internal organs and congenital heart disease in humans. Ccdc11 is a novel component of centriolar satellites and plays a critical role in motile and sensory ciliogenesis. The results implicate centriolar satellites in the pathology of left–right patterning and heart disease.

The establishment of left–right (L-R) asymmetry in vertebrates is dependent on the sensory and motile functions of cilia during embryogenesis. Mutations in CCDC11 disrupt L-R asymmetry and cause congenital heart disease in humans, yet the molecular and cellular functions of the protein remain unknown. Here we demonstrate that Ccdc11 is a novel component of centriolar satellites—cytoplasmic granules that serve as recruitment sites for proteins destined for the centrosome and cilium. Ccdc11 interacts with core components of satellites, and its loss disrupts the subcellular organization of satellite proteins and perturbs primary cilium assembly. Ccdc11 colocalizes with satellite proteins in human multiciliated tracheal epithelia, and its loss inhibits motile ciliogenesis. Similarly, depletion of CCDC11 in Xenopus embryos causes defective assembly and motility of cilia in multiciliated epidermal cells. To determine the role of CCDC11 during vertebrate development, we generated mutant alleles in zebrafish. Loss of CCDC11 leads to defective ciliogenesis in the pronephros and within the Kupffer’s vesicle and results in aberrant L-R axis determination. Our results highlight a critical role for Ccdc11 in the assembly and function of motile cilia and implicate centriolar satellite–associated proteins as a new class of proteins in the pathology of L-R patterning and congenital heart disease.

From the radiologic pathology archives: pediatric polycystic kidney disease and other ciliopathies: radiologic-pathologic correlation

Genetic defects of cilia cause a wide range of diseases, collectively known as ciliopathies. Primary, or nonmotile, cilia function as sensory organelles involved in the regulation of cell growth, differentiation, and homeostasis. Cilia are present in nearly every cell in the body and mutations of genes encoding ciliary proteins affect multiple organs, including the kidneys, liver, pancreas, retina, central nervous system (CNS), and skeletal system. Genetic mutations causing ciliary dysfunction result in a large number of heterogeneous phenotypes that can manifest with a variety of overlapping abnormalities in multiple organ systems. Renal manifestations of ciliopathies are the most common abnormalities and include collecting duct dilatation and cyst formation in autosomal recessive polycystic kidney disease (ARPKD), cyst formation anywhere in the nephron in autosomal dominant polycystic kidney disease (ADPKD), and tubulointerstitial fibrosis in nephronophthisis, as well as in several CNS and skeletal malformation syndromes. Hepatic disease is another common manifestation of ciliopathies, ranging from duct dilatation and cyst formation in ARPKD and ADPKD to periportal fibrosis in ARPKD and several malformation syndromes. The unifying molecular pathogenesis of this emerging class of disorders explains the overlap of abnormalities in disparate organ systems and links diseases of widely varied clinical features. It is important for radiologists to be able to recognize the multisystem manifestations of these syndromes, as imaging plays an important role in diagnosis and follow-up of affected patients.

CNS involvement in OFD1 syndrome: a clinical, molecular, and neuroimaging study

Background

Oral-facial-digital type 1 syndrome (OFD1; OMIM 311200) belongs to the expanding group of disorders ascribed to ciliary dysfunction. With the aim of contributing to the understanding of the role of primary cilia in the central nervous system (CNS), we performed a thorough characterization of CNS involvement observed in this disorder.

Methods

A cohort of 117 molecularly diagnosed OFD type I patients was screened for the presence of neurological symptoms and/or cognitive/behavioral abnormalities on the basis of the available information supplied by the collaborating clinicians. Seventy-one cases showing CNS involvement were further investigated through neuroimaging studies and neuropsychological testing.

Results

Seventeen patients were molecularly diagnosed in the course of this study and five of these represent new mutations never reported before. Among patients displaying neurological symptoms and/or cognitive/behavioral abnormalities, we identified brain structural anomalies in 88.7%, cognitive impairment in 68%, and associated neurological disorders and signs in 53% of cases. The most frequently observed brain structural anomalies included agenesis of the corpus callosum and neuronal migration/organisation disorders as well as intracerebral cysts, porencephaly and cerebellar malformations.

Conclusions

Our results support recent published findings indicating that CNS involvement in this condition is found in more than 60% of cases. Our findings correlate well with the kind of brain developmental anomalies described in other ciliopathies. Interestingly, we also described specific neuropsychological aspects such as reduced ability in processing verbal information, slow thought process, difficulties in attention and concentration, and notably, long-term memory deficits which may indicate a specific role of OFD1 and/or primary cilia in higher brain functions.

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.

Centriolar satellites: busy orbits around the centrosome

Since its first description by Theodor Boveri in 1888, the centrosome has been studied intensely, and it revealed detailed information about its structure, molecular composition and its various functions. The centrosome consists of two centrioles, which generally appear in electron microscopy as barrel-shaped structures usually composed of nine microtubule triplets. An amorphous mass of pericentriolar material surrounds the centrioles and accumulates many proteins important for the integrity and function of centrosomes, such as the γ-tubulin ring complex (γ-TuRC) that mediates microtubule nucleation and capping. In animal somatic cells, the centrosome generally accounts for the major microtubule organizing center, and the duplicated pair of centrosomes determines the poles of the microtubule-based mitotic spindle. Despite detailed insights into the centrosome's structure and function, it has been a complete mystery until a few years ago how centrosomes duplicate and assemble. Moreover, it is still largely unclear if and how centrosomal proteins or protein complexes are exchanged, replaced or qualitatively altered. Previously identified cytoplasmic granules, named "pericentriolar" or "centriolar satellites", might fulfil such functions in protein targeting and exchange, and communication between the centrosomes and the cytoplasm. In this review, we summarize current knowledge about the structure, molecular composition and possible roles of the satellites that seem to surround the core of the centrosome in most animal cells.

Centriolar satellites are assembly points for proteins implicated in human ciliopathies, including oral-facial-digital syndrome 1

Ciliopathies are caused by mutations in genes encoding proteins required for cilia organization or function. We show through colocalization with PCM-1, that OFD1 (the product of the gene mutated in oral-facial-digital syndrome 1) as well as BBS4 and CEP290 (proteins encoded by other ciliopathy genes) are primarily components of centriolar satellites, the particles surrounding centrosomes and basal bodies. RNA interference experiments reveal that satellite integrity is mutually dependent upon each of these proteins. Upon satellite dispersal, through mitosis or forced microtubule depolymerization, OFD1 and CEP290 remain centrosomal, whereas BBS4 and PCM-1 do not. OFD1 interacts via its fifth coiled-coil motif with the N-terminal coiled-coil domain of PCM-1, which itself interacts via its C-terminal non-coiled-coil region with BBS4. OFD1 localization to satellites requires its N-terminal region, encompassing the LisH motif, whereas expression of OFD1 C-terminal constructs causes PCM-1 and CEP290 mislocalization. Moreover, in embryonic zebrafish, OFD1 and BBS4 functionally synergize, determining morphogenesis. Our observation that satellites are assembly points for several mutually dependent ciliopathy proteins provides a further possible explanation as to why the clinical spectrum of OFD1, Bardet-Biedl and Joubert syndromes overlap. Furthermore, definition of how OFD1 and PCM-1 interact helps explain why different OFD1 mutations lead to clinically variable phenotypes.

Fibrocystic disease of liver and pancreas; under-recognized features of the X-linked ciliopathy oral-facial-digital syndrome type 1 (OFD I)

OFD I is an X-linked dominant male-lethal ciliopathy characterized by prominent external features including oral clefts, hamartomas or cysts of the tongue, and digital anomalies. Although these external features are easy to recognize and often lead to diagnosis in early childhood, visceral findings in OFD I, especially the fibrocystic liver and pancreas disease, are under-recognized. In addition, while the occurrence of polycystic kidney disease (PKD) in OFD I is well known, few patients are evaluated and monitored for this complication. We report on two adult females diagnosed with OFD I in infancy, but not evaluated for visceral involvement. In adulthood, they were incidentally found to have severe hypertension and chronic renal insufficiency due to undiagnosed PKD. A pancreatic cystic lesion, also discovered incidentally, was thought to be malignant and led to consideration of major surgery. We present NIH evaluations, including documentation of OFD I mutations, extreme beading of the intrahepatic bile ducts, pancreatic cysts, and tabulate features of reported OFD I cases having hepatic, pancreatic, and renal cystic disease. Liver and pancreas are not routinely evaluated in OFD I patients. Increased awareness and lifelong monitoring of visceral complications, particularly involving the liver, pancreas, and kidney, are essential for timely and accurate treatment.