Novel KIAA0753 mutations extend the phenotype of skeletal ciliopathies.

The skeletal ciliopathies are a heterogeneous group of disorders with a significant clinical and genetic variability and the main clinical features are thoracic hypoplasia and short tubular bones. To date, 25 genes have been identified in association with skeletal ciliopathies. Mutations in the KIAA0753 gene have recently been associated with Joubert syndrome (JBTS) and orofaciodigital (OFD) syndrome. We report biallelic pathogenic variants in KIAA0753 in four patients with short-rib type skeletal dysplasia. The manifestations in our patients are variable and ranging from fetal lethal to viable and moderate skeletal dysplasia with narrow thorax and abnormal metaphyses. We demonstrate that KIAA0753 is expressed in normal fetal human growth plate and show that the affected fetus, with a compound heterozygous frameshift and a nonsense mutation in KIAA0753, has an abnormal proliferative zone and a broad hypertrophic zone. The importance of KIAA0753 for normal skeletal development is further confirmed by our findings that zebrafish embryos homozygous for a nonsense mutation in kiaa0753 display altered cartilage patterning.

Expanding the allelic disorders linked to TCTN1 to include Varadi syndrome (Orofaciodigital syndrome type VI).

Varadi syndrome is a subtype of orofaciodigital syndrome (OFDS) that combines the typical features of OFDS and the posterior fossa features of Joubert syndrome. The only gene known to be mutated in Varadi syndrome is C5ORF42. In this report, we describe the phenotype of a patient with Varadi syndrome who is homozygous for a previously reported mutation in TCTN1 (NM_001082538.2:c.342-2A>G, p.Gly115Lysfs*8) and suggest that allelic disorders linked to TCTN1 include Varadi syndrome, in addition to Joubert syndrome and Meckel-Gruber syndrome.

Oral-facial-digital syndrome type 1 in males: Congenital heart defects are included in its phenotypic spectrum.

Oral-facial-digital syndrome type 1 (OFD1; OMIM# 311200) is an X-linked dominant ciliopathy caused by mutations in the OFD1 gene. This condition is characterized by facial anomalies and abnormalities of oral tissues, digits, brain, and kidneys. Almost all affected patients are female, as OFD1 is presumed to be lethal in males, mostly in the first or second trimester of pregnancy. Live born males with OFD1 are a rare occurrence, with only five reported patients to date. In four patients the presence of a congenital heart defect (CHD) was observed. Here, we report an affected male fetus with a hemizygous de novo mutation in OFD1 (c.2101C>T; p.(Gln701*)). Ultrasound examination demonstrated severe hydrocephalus, a hypoplastic cerebellum and a hypoplastic left ventricle of the heart. The pregnancy was terminated at 16 weeks of gestation because of poor prognosis. Post-mortem examination of the fetus confirmed severe hypoplasia of the left ventricle of the heart. We emphasize that CHDs should be included in the phenotypic spectrum of OFD1 in males. This justifies molecular analysis of OFD1 when CHD is encountered prenatally in combination with one or more phenotypic features previously described in the OFD1 gene alteration spectrum. The underlying pathogenesis of CHD in OFD1 (and other ciliopathies) probably involves dysfunction of the primary cilia regarding coordination of left-right signalling during early heart development. Whether these CHDs wholly or partly result from defective left right signalling, in which different types of cilia are known to play a critical role, remains a topic of research.

Autosomal recessive IFT57 hypomorphic mutation cause ciliary transport defect in unclassified oral-facial-digital syndrome with short stature and brachymesophalangia.

The 13 subtypes of oral-facial-digital syndrome (OFDS) belong to the heterogeneous group of ciliopathies. Disease-causing genes encode for centrosomal proteins, components of the transition zone or proteins implicated in ciliary signaling. A unique consanguineous family presenting with an unclassified OFDS with skeletal dysplasia and brachymesophalangia was explored. Homozygosity mapping and exome sequencing led to the identification of a homozygous mutation in IFT57, which encodes a protein implicated in ciliary transport. The mutation caused splicing anomalies with reduced expression of the wild-type transcript and protein. Both anterograde ciliary transport and sonic hedgehog signaling were significantly decreased in subjects' fibroblasts compared with controls. Sanger sequencing of IFT57 in 13 OFDS subjects and 12 subjects with Ellis-Van Creveld syndrome was negative. This report identifies the implication of IFT57 in human pathology and highlights the first description of a ciliary transport defect in OFDS, extending the genetic heterogeneity of this subgroup of ciliopathies.

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.

Oro-facial-digital syndrome type 1: a case report.

Oro-Facial Digital Syndrome (OFDS) is a generic term for group of apparently distinctive genetic diseases that affect the development of the oral cavity, facial features, and digits. One of these is OFDS type I (OFDS-I) which has rarely been reported in Asian countries. This is the case report of a 13 year old patient with OFDS type I who reported to the Department of Pedodontics and Preventive Dentistry, with the complaint of discolored upper front teeth.

Developmental disorders of the dentition: an update.

Dental anomalies are common congenital malformations that can occur either as isolated findings or as part of a syndrome. This review focuses on genetic causes of abnormal tooth development and the implications of these abnormalities for clinical care. As an introduction, we describe general insights into the genetics of tooth development obtained from mouse and zebrafish models. This is followed by a discussion of isolated as well as syndromic tooth agenesis, including Van der Woude syndrome (VWS), ectodermal dysplasias (EDs), oral-facial-digital (OFD) syndrome type I, Rieger syndrome, holoprosencephaly, and tooth anomalies associated with cleft lip and palate. Next, we review delayed formation and eruption of teeth, as well as abnormalities in tooth size, shape, and form. Finally, isolated and syndromic causes of supernumerary teeth are considered, including cleidocranial dysplasia and Gardner syndrome.

[Simple febrile seizure, complex seizure, generalized epilepsy with febrile seizure plus, FIRES and new syndromes]. / Crisis febriles simples y complejas, epilepsia generalizada con crisis febriles plus, FIRES y nuevos síndromes.

Febrile seizures are the most common seizures in childhood. They have been observed in 2-5% of children before the age of 5, but in some populations this figure may increase to 15%. It is a common cause of pediatric hospital admissions and cause of anxiety for parents. Febrile seizures could be the first manifestation of epilepsy. About 13% of epileptic patients have a history of febrile seizure, and 30% have had recurrent febrile seizures. Their phenotypic characteristics allow, in the majority of cases, a classification of the seizure, an elaboration of a prognosis and to assume a specific therapeutic attitude. It is possible to describe a spectrum according to their severity, from the benign simple seizure to the more complex, febrile seizure plus, Dravet'syndrome, and FIRES. During the past decade, molecular genetic studies have contributed to the identification of genetic factors involved in febrile seizure and related disorders, making the necessity of a careful follow up of these patients in order to detect risk factors earlier. We have reviewed the medical literature to update current knowledge of febrile seizures, their prognosis and their relation to new epileptic syndromes.

Crisis febriles simples y complejas, epilepsia generalizada con crisis febriles plus, FIRES y nuevos síndromes / [Simple febrile seizure, complex seizure, generalized epilepsy with febrile seizure plus, FIRES and new syndromes].

Febrile seizures are the most common seizures in childhood. They have been observed in 2-5

of children before the age of 5, but in some populations this figure may increase to 15

. It is a common cause of pediatric hospital admissions and cause of anxiety for parents. Febrile seizures could be the first manifestation of epilepsy. About 13

of epileptic patients have a history of febrile seizure, and 30

have had recurrent febrile seizures. Their phenotypic characteristics allow, in the majority of cases, a classification of the seizure, an elaboration of a prognosis and to assume a specific therapeutic attitude. It is possible to describe a spectrum according to their severity, from the benign simple seizure to the more complex, febrile seizure plus, Dravet’syndrome, and FIRES. During the past decade, molecular genetic studies have contributed to the identification of genetic factors involved in febrile seizure and related disorders, making the necessity of a careful follow up of these patients in order to detect risk factors earlier. We have reviewed the medical literature to update current knowledge of febrile seizures, their prognosis and their relation to new epileptic syndromes.

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

The oral-facial-digital syndrome type I (OFD I) is characterized by multiple congenital malformations of the face, oral cavity and digits. A polycystic kidney disease (PKD) is found in about one-third of patients but long-term outcome and complications are not well described in the international literature. Renal findings have been retrospectively collected in a cohort of 34 females all carrying a pathogenic mutation in the OFD1 gene with ages ranging from 1 to 65 years. Twelve patients presented with PKD - 11/16 (69%) if only adults were considered -with a median age at diagnosis of 29 years [IQR (interquartile range) = (23.5-38)]. Among them, 10 also presented with renal impairment and 6 were grafted (median age = 38 years [IQR = (25-48)]. One grafted patient under immunosuppressive treatment died from a tumor originated from a native kidney. The probability to develop renal failure was estimated to be more than 50% after the age of 36 years. Besides, neither genotype-phenotype correlation nor clinical predictive association with renal failure could be evidenced. These data reveal an unsuspected high incidence rate of the renal impairment outcome in OFD I syndrome. A systematic ultrasound (US) and renal function follow-up is therefore highly recommended for all OFD I patients.

Convergent extension movements and ciliary function are mediated by ofd1, a zebrafish orthologue of the human oral-facial-digital type 1 syndrome gene.

In humans, OFD1 is mutated in oral-facial-digital type I syndrome leading to prenatal death in hemizygous males and dysmorphic faces and brain malformations, with polycystic kidneys presenting later in life in heterozygous females. To elucidate the function of Ofd1, we have studied its function during zebrafish embryonic development. In wild-type embryos, ofd1 mRNA is widely expressed and Ofd1-green fluorescent protein (GFP) fusion localizes to the centrosome/basal body. Disrupting Ofd1 using antisense morpholinos (MOs) led to bent body axes, hydrocephalus and oedema. Laterality was randomized in the brain, heart and viscera, likely a consequence of shorter cilia with disrupted axonemes and perturbed intravesicular fluid flow in Kupffer's vesicle. Embryos injected with ofd1 MOs also displayed convergent extension (CE) defects, which were enhanced by loss of Slb/Wnt11 or Tri/Vangl2, two proteins functioning in a non-canonical Wnt/Planar Cell Polarity (PCP) pathway. Pronephric glomerular midline fusion was compromised in vangl2 and ofd1 loss of function embryos and we suggest this anomaly may be a novel CE defect. Thus, Ofd1 is required for ciliary motility and function in zebrafish, supporting data showing that Ofd1 is essential for primary cilia function in mice. In addition, our data show that Ofd1 is important for CE during gastrulation, consistent with data linking primary cilia and non-canonical Wnt/PCP signalling.

Making sense of cilia and flagella.

Data reported at an international meeting on the sensory and motile functions of cilia, including the primary cilium found on most cells in the human body, have thrust this organelle to the forefront of studies on the cell biology of human disease.

Prenatal diagnosis of episodic tachypnea in an infant with OFD VI.

Episodic tachypnea is a typical neonatal presentation of Joubert syndrome, but may also occur in infants with other anomalies of the cerebellar vermis. Even though fetuses at risk for Joubert syndrome are usually closely followed by ultrasound, this respiratory pattern has only once been described prenatally. We describe a patient who presented prenatally with posterior meningocele, Dandy-Walker cyst, and four limb polydactyly on ultrasound. Amniocentesis showed a normal male karyotype and normal 7DHC. At 31 weeks, episodic fetal tachypnea was noted on ultrasound. The working diagnosis was Joubert syndrome or oro-facio-digital syndrome type VI (OFD VI). At birth, in addition to the findings noted prenatally, he had multiple nodules of his tongue, a Y-shaped metacarpal and micropenis. His respiratory pattern was notable for alternating tachypnea and apnea with respiratory rates up to 200 followed by apnea and bradycardia. Magnetic resonance image showed Dandy-Walker with massive 4th ventricle, complete absence of the cerebellar vermis, hypoplastic brainstem, and small meningocele. Development is profoundly delayed and he remains ventilator dependent. Both the previously described Joubert patient with prenatally recognized tachypnea, and our patient are atypical for Joubert syndrome since they have polydactyly (which occurs in only 8% of Joubert patients) and hamartomas of the tongue (which occur in 2%). Despite the tongue hamartomas, these patients are not entirely typical for OFD VI, since their polydactyly is postaxial. The observation of prenatal tachypnea in these two patients, but not in typical Joubert patients, suggests they have either a variant of OFD VI or a new Joubert or OFD-like syndrome.

The contribution of electromyography to the diagnostics of some rare palatal anomalies.

The paper presents the electromyographic (EMG) findings of the soft palate in three patients: a patient with Mohr syndrome and cleft palate, a patient with palatal asymmetry and rhinolalia and a patient with vertical oro-ocular facial cleft with marked asymmetry of the cleft palate. In the first patient, electrical silence was registered in one half of the palate. In the second patient, moderate loss of active motor units was registered in the hypoplastic part of the palate. In the third patient, in spite of asymmetry, the EMG finding was normal on both sides of the palate.

Combined anomalies of the palate in Mohr syndrome: is preoperative electromyography of the palate useful?

The authors present a girl with typical characteristics of oral-facial-digital syndrome type II (Mohr syndrome) with a cleft soft palate and pendulous tongue nodules. Because of feeding difficulties, electromyography was performed of both morphologically identical halves of the soft palate. One half showed a normal muscle action potential and in the other half electrical silence was registered. Exploratory surgery during palatoplasty showed a fatty hamartoma in the half of the palate in which no electric potentials had been registered.