Hemiarhinia caused by a missense variation in SMCHD1: A mild phenotype in the clinical spectrum of Bosma arhinia microphthalmia syndrome.

Bosma arhinia microphthalmia syndrome (BAMS, OMIM #603457) is a rare autosomal dominant disorder caused by heterozygous variation in the SMCHD1 gene on chromosome 18p11. Clinically, it is characterized by microphthalmia, absence or hypoplasia of nose, choanal atresia, anosmia, palatal abnormalities, hypogonadotropic hypogonadism, and cryptorchidism. Here we report a Brazilian patient with a likely pathogenic variation in SMCHD1 gene (c.1418A>T; p.Glu473Val) presenting hemiarhinia associated with short stature and hypogonadotropic hypogonadism. Due to the clinical variability of BAMS, we considered that hemiarhinia, without microphthalmia, in the present case, can be considered a mild form of BAMS and could be considered for screening of SMCHD1 gene variation.

Dilemmas in the management of lacrimal drainage anomalies in BOSMA (congenital arhinia-microphthalmia) syndrome.

Congenital arhinia-microphthalmos syndrome or BOSMA syndrome is an exceptionally rare clinical syndrome characterized by unilateral or bilateral complete absence of the nasal cavity associated with several craniofacial, ocular, and systemic anomalies. Lacrimal drainage anomalies are secondary to absent nasolacrimal duct and usually present as dilated lacrimal sac or mucoceles. While navigation-guided dacryocystorhinostomies into the contralateral nasal cavity are described for unilateral arhinia, the way forward for the complete absence of the nose and nasal cavity is still unclear. A multidisciplinary team from the specialties of genetics, plastic surgery, ophthalmic plastics and reconstructive surgery, otorhinolaryngology, and endocrinology should get involved very early on for better continuity of care.

The Epigenetic Regulator SMCHD1 in Development and Disease.

It has very recently become clear that the epigenetic modifier SMCHD1 has a role in two distinct disorders: facioscapulohumoral muscular dystrophy (FSHD) and Bosma arhinia and micropthalmia (BAMS). In the former there are heterozygous loss-of-function mutations, while both gain- and loss-of-function mutations have been proposed to underlie the latter. These findings have led to much interest in SMCHD1 and how it works at the molecular level. We summarise here current understanding of the mechanism of action of SMCHD1, its role in these diseases, and what has been learnt from study of mouse models null for Smchd1 in the decade since the discovery of SMCHD1.

Image-guided lacrimal drainage surgery in congenital arhinia-microphthalmia syndrome.

The aim of this study was to illustrate the surgical techniques and utility of stereotactic or image-guided navigation in the management of lacrimal drainage obstruction in congenital arhinia-microphtalmia syndrome and review the relevant literature. Image-guided combined external and endoscopic dacryocystorhinostomy was performed in a female, aged 16 years with congenital partial arhinia and ipsilateral microphthalmus. The lacrimal sac was bypassed to the contra lateral nasal cavity through a septal window. The surgical procedure was performed using the intra-operative optical image-guided Nav 1 PicoTM ENT navigation system with real-time intra-operative instrument geometry. Different phases of the surgical technique, adjunctive endoscopic procedures, intra-operative anatomical guidance, and utility at crucial phases of surgery were noted. A review of the literature was performed pertinent to arhinia and navigation guided lacrimal surgeries. Lacrimal bypass into the contra lateral nasal cavity even through a malformed septum is possible in partial arhinia syndromes. Detailed preoperative evaluation including 3D imaging studies, navigation guided planning of risk structures with intra-operative distance control and construction of meticulous surgical roadmaps were found to be essential factors in successful outcomes. At six months follow up after surgery, there was a complete and contiguous healed mucosal anastomosis with lacrimal system patent on irrigation and resolution of epiphora. Combined external and endoscopic approach is useful in partial arhinia syndromes. Image guidance is a very useful adjunctive tool that facilitates safe and precise surgery in the management of such complex lacrimal surgeries.

Bosma arhinia microphthalmia syndrome: Clinical report and review of the literature.

Bosma arhinia microphthalmia syndrome (Bosma syndrome)(OMIM 603457) is a congenital condition characterized by microphthalmia with coloboma, arhinia and endocrine findings in the setting of normal intelligence and brain structure. This condition is quite rare with fewer than 50 case reports and series. Although pathogenesis is presumed to be genetic, the cause remains unknown. We report an individual with Bosma syndrome who had bilateral colobomatous microphthalmia, arhinia, high arched palate, mild ear malformations, and hypogonadotropic hypogonadism requiring growth hormone treatment in childhood, and normal intelligence. Clinical evaluation was significant for a geometrically abnormal aorta with effacement of the sinotubular ridge, a finding not previously reported in this condition. An MRI revealed absent olfactory bulbs. Suggested criteria for diagnosis of Bosma should include arhinia, hypoplastic maxilla, normal cognition, and hypogonadotropic hypogonadism in males.

[Some features of the nose in craniofacial malformations]. / Quelques particularités du nez dans les malformations crânio-faciales (fentes labio-palatines exclues).

In craniofacial malformations, the nose is variably affected: in its location, its shape or by lack of development. In this short chapter, some of the common problems encountered by the specialized teams are summarized. Craniofacial astronomies can modify the skeleton of the nose during growth, sometime at an early age. However, most rhinoplasties are performed at adulthood. The nasal pyramid may present deformations that produce functional and aesthetics impairment that should be treated when necessary. Respiratory problems should be recognized as early as possible and treated in priority.

Identification of a pathogenic SMCHD1 variant in a Chinese patient with bosma arhinia microphthalmia syndrome: a case report.

BACKGROUND: Bosma arhinia microphthalmia syndrome (BAMS; MIM603457) is a rare genetic disorder, predominantly autosomal dominant. It is a multi-system developmental disorder characterized by severe hypoplasia of the nose and eyes, and reproductive system defects. BAMS is extremely rare in the world and no cases have been reported in Chinese population so far. Pathogenic variants in the SMCHD1 gene (MIM614982) cause BAMS, while the underlying molecular mechanisms requires further investigation. CASE PRESENTATION: In this study, a Chinese girl who has suffered from congenital absence of nose and microphthalmia was enrolled and subsequently submitted to a comprehensive clinical and genetic evaluation. Whole-exome sequencing (WES) was employed to identify the genetic entity of thisgirl. A heterozygous pathogenic variant, NM_015295, c.1025G > C; p. (Trp342Ser) of SMCHD1 was identified. By performing very detailed physical and genetic examinations, the patient was diagnosed as BAMS. CONCLUSION: This report is the first description of a variant in SMCHD1 in a Chinese patient affected with BAMS.Our study not only furnished valuable genetic data for counseling of BAMS, but also confirmed the diagnosis of BAMS, which may help the management and prognosis for this patient.

Bosma Arhinia Microphthalmia Syndrome (BAMS): First Report from Vietnam.

Bosma arhinia microphthalmia syndrome (BAMS) is a rare condition, with about 100 cases identified worldwide. It is characterized by nasal and ophthalmic abnormalities, as well as disturbances in puberty and sexual development. The cardinal sign is arhinia, though some cases have partial aplasia of the external nose. In addition, several reports have revealed abnormal brain structure, including changes to the olfactory bulbs. This case describes a 29-year-old female who has suffered from BAMS since birth. On presentation, she was noted to have congenital arhinia, bilateral microphthalmia, vision loss, mouth-breathing, an unclear speaking voice, a high arched or cleft palate, and a hypoplastic maxilla. Her paranasal sinuses were ossified and underdeveloped. This syndrome occurs rarely, both within Vietnam and worldwide. It is characterized by four major features: arrhinia, complete absence of the paranasal sinuses, eye defects, and absent sexual maturation. This case report describes the presentation of the disorder to improve otolaryngologists' understanding of BAMS. Criteria for diagnosis consist of arhinia, midface hypoplasia (with a hypoplastic maxilla), hypogonadotropic hypogonadism, and normal intellectual abilities. Additional important findings are microphthalmia with or without coloboma, anosmia, maxillary hypoplasia, a high-arched palate, and absence of paranasal sinuses and olfactory bulbs.

Congenital hyporhinia with associated malformations: Case report of a rare congenital anomaly.

Congenital hyporhinia, also known as partial arhinia, is a very rare congenital abnormality of nasal embryogenesis with unknown etiology. It is commonly associated with other craniofacial anomalies which are thought to be caused by an absent or rudimentary nose. A 3-h-old neonate presented to our facility with hypoplastic nasal pyramid, hypertelorism, microcephaly, and micrognathia, a case of congenital hyporhinia with associated anomalies is presented and the embryology and literature review are discussed.

Congenital Arhinia: A Neonatal Case Report.

Congenital arhinia or nasal absence is a rare condition, with only less than 100 cases published in the literature to date. It is a rare condition that causes respiratory distress during the neonatal period. Although stabilization of the airway is the priority, management is not clearly defined, given the rarity of the malformation. We report a case of arhinia in a female newborn and briefly review the literature.

Congenital complete arhinia with alobar holoprosencephaly.

Congenital arhinia is a life-threatening, rare craniofacial disorder, which, when not identified and managed early can cause severe respiratory distress at birth due to upper airway obstruction. Since neonates are obligate nasal breathers, simultaneous sucking and breathing requirement in neonates with arhinia leads to respiratory distress. Inspiration and expiration through the oral passage alone may result in thoracic retraction, thereby further exacerbating respiratory distress. We report a rare case of congenital complete arhinia with alobar holoprosencephaly in a 9-month-old. With no family history of congenital malformations, maternal risk factors and uneventful pregnancy, a term female neonate was delivered vaginally without immediate post-delivery respiratory distress. Examination revealed microcephaly, absent fontanelles, fused cranial sutures and bilateral microphthalmia. Breathing was spontaneous, with no immediate signs of respiratory distress. An additional diagnosis of alobar holoprosencephaly was made after a head computed tomography (CT) scan was done. Management included the initial stabilisation phase of supplemental oxygen and an orogastric tube for feeding. The baby did not require both tracheostomy and gastrostomy tubes, as she was not in severe respiratory distress requiring a tracheostomy tube nor having difficulties feeding with the orogastric tube.

Congenital Partial Arhinia.

Background: Partial arhinia is an extremely rare congenital malformation with an unclear pathogenesis. In this condition, the external nasal structures and nasal passages are absent, and it can be associated with somatic anomalies, other craniofacial abnormalities, severe feeding, and airway compromise. Objective: In this article, we describe a case of a baby born with congenital partial arhinia at Prince Rashid AlHasan Hospital in Irbid, Jordan. Case presentation: Her condition was associated with microcephaly, hypotelorism, cleft palate, microphthalmia, and micrognathia. The baby was the result of an unplanned pregnancy; the mother had received a Zoladex implant 2 months before the pregnancy as a treatment for endometriosis. Conclusion: Congenital partial arhinia could be associated with dangerous life-threatening complications such as feeding and airway compromise. Management of the condition is essential and urgent, including surgical correction as needed by a highly skilled team.

Prenatal Diagnosis of Arhinia.

Arhinia is a rare congenital anomaly that is not typically associated with known genetic mutations and is usually discovered after an affected infant is born. Prenatal diagnosis is important because neonates with arhinia often require specialized respiratory support with creation of an artificial airway. We present a case of isolated arhinia diagnosed on second-trimester ultrasound. A patient presented for routine ultrasound at 18 weeks gestation, and nasal tissues were absent in an otherwise morphologically normal appearing fetus. Cell free fetal DNA was unremarkable. The patient elected to undergo termination of pregnancy by dilation and evacuation. Subsequent genetic analysis confirmed a normal fetal karyotype and microarray, and no examination of fetal structural anatomy was possible. Antenatal diagnosis of arhinia is important to guide maternal-fetal care decisions and requires methodical sonographic evaluation to identify this malformation prior to delivery.

Congenital bony nasal cavity stenosis: A review of current trends in diagnosis and treatment.

Congenital bony nasal cavity stenosis is caused by alterations of the normal embryological development of the nasal cavity. Depending on the site of the obstruction, the most important types of stenosis are: choanal atresia and stenosis, congenital nasal pyriform aperture stenosis, congenital midnasal stenosis, arhinia and nasal septum deviation. Although they are uncommon, they could be potentially life-threatening conditions that require early diagnosis and proper treatment. In case of neonatal nasal obstruction, appropriate differential diagnosis with other causes, such as rhinitis and sinonasal masses, are performed by nasal endoscopy and radiological exams. Treatment strategy consisting of medical nasal therapies and endoscopic or open nasal surgery should be tailored according to the types and the degree of the stenosis. When indicated, endoscopic endonasal approach is considered the most effective technique in neonates warranting minimal surgical invasiveness and maximum effect. In order to promote the management of these rare yet clinically relevant neonatal nasal breath disorders, we review the current trends in diagnosis and treatment of congenital bony nasal cavity stenosis.

AKT Signaling Modifies the Balance between Cell Proliferation and Migration in Neural Crest Cells from Patients Affected with Bosma Arhinia and Microphthalmia Syndrome.

Over the recent years, the SMCHD1 (Structural Maintenance of Chromosome flexible Hinge Domain Containing 1) chromatin-associated factor has triggered increasing interest after the identification of variants in three rare and unrelated diseases, type 2 Facio Scapulo Humeral Dystrophy (FSHD2), Bosma Arhinia and Microphthalmia Syndrome (BAMS), and the more recently isolated hypogonadotrophic hypogonadism (IHH) combined pituitary hormone deficiency (CPHD) and septo-optic dysplasia (SOD). However, it remains unclear why certain mutations lead to a specific muscle defect in FSHD while other are associated with severe congenital anomalies. To gain further insights into the specificity of SMCHD1 variants and identify pathways associated with the BAMS phenotype and related neural crest defects, we derived induced pluripotent stem cells from patients carrying a mutation in this gene. We differentiated these cells in neural crest stem cells and analyzed their transcriptome by RNA-Seq. Besides classical differential expression analyses, we analyzed our data using MOGAMUN, an algorithm allowing the extraction of active modules by integrating differential expression data with biological networks. We found that in BAMS neural crest cells, all subnetworks that are associated with differentially expressed genes converge toward a predominant role for AKT signaling in the control of the cell proliferation-migration balance. Our findings provide further insights into the distinct mechanism by which defects in neural crest migration might contribute to the craniofacial anomalies in BAMS.

Insight Into the Ontogeny of GnRH Neurons From Patients Born Without a Nose.

CONTEXT: The reproductive axis is controlled by a network of gonadotropin-releasing hormone (GnRH) neurons born in the primitive nose that migrate to the hypothalamus alongside axons of the olfactory system. The observation that congenital anosmia (inability to smell) is often associated with GnRH deficiency in humans led to the prevailing view that GnRH neurons depend on olfactory structures to reach the brain, but this hypothesis has not been confirmed. OBJECTIVE: The objective of this work is to determine the potential for normal reproductive function in the setting of completely absent internal and external olfactory structures. METHODS: We conducted comprehensive phenotyping studies in 11 patients with congenital arhinia. These studies were augmented by review of medical records and study questionnaires in another 40 international patients. RESULTS: All male patients demonstrated clinical and/or biochemical signs of GnRH deficiency, and the 5 men studied in person had no luteinizing hormone (LH) pulses, suggesting absent GnRH activity. The 6 women studied in person also had apulsatile LH profiles, yet 3 had spontaneous breast development and 2 women (studied from afar) had normal breast development and menstrual cycles, suggesting a fully intact reproductive axis. Administration of pulsatile GnRH to 2 GnRH-deficient patients revealed normal pituitary responsiveness but gonadal failure in the male patient. CONCLUSIONS: Patients with arhinia teach us that the GnRH neuron, a key gatekeeper of the reproductive axis, is associated with but may not depend on olfactory structures for normal migration and function, and more broadly, illustrate the power of extreme human phenotypes in answering fundamental questions about human embryology.

The Case of the Missing Nose: Congenital Arhinia Case Presentation and Management Recommendations.

OBJECTIVES: To discuss the presentation and management of infants with arhinia or congenital absence of the nose. METHODS: This case report describes an infant with arhinia that was diagnosed prenatally. In addition to a discussion of the case, a review of the literature was completed to define appropriate postnatal work-up and management. RESULTS: The patient is a term male infant, diagnosed with arhinia on ultrasound and magnetic resonance imaging (MRI) performed at 21-weeks gestational age. Upon birth, the patient was subsequently intubated, followed by tracheostomy due to complete nasal obstruction. Through a genetics evaluation, the patient was found to be heterozygous for the SMCHD1 gene, with hypomethylation at the D4Z4 locus. Plans for reconstruction will be based on future imaging and the development of any nasal patency, however, the patient's family plans to utilize a prosthetic nose until the patient is older. CONCLUSION: Arhinia is a rare condition causing respiratory distress in the neonatal period. While stabilization of the airway is the first priority, further management is not clearly defined given the rarity of the malformation. This case discusses stabilization of the airway with a review of treatment and reconstructive options.

Nasal Reconstruction Using a Customized Three-Dimensional-Printed Stent for Congenital Arhinia: Three-Year Follow-up.

A male Mongolian child with a complete congenital absence of both nose and nasal passage had a poor survival prognosis due to respiratory distress. To enable his survival, a new nose capable of conferring respiratory function was constructed. Following reconstructive surgery, an absence of mucoepithelium in the nasal passage can lead to rhinostenosis. To avoid this complication, a custom-made nasal silicone stent was created using three-dimensional (3D) printing technology in conjunction with the patient's computed tomography data. The stent was implanted for 2 months to maintain the shape and size of the nasal passage. At 2 months after stent implantation, the mucoepithelium tissue in the passage had successfully regenerated with no immune reaction. Three years after stent removal, respiratory function, nasal passage structure, and external nose shape were maintained without additional medical care. These results indicate the successful nasal reconstruction in an arhinia patient using a customized, 3D-printed nasal stent. Laryngoscope, 129:582-585, 2019.

Design and manufacturing of a patient-specific nasal implant for congenital arhinia: Case report.

Arhinia (congenital absence of the nose) is a congenital rare disease, which has been reported in less than 60 cases in the literature. It consists of the absence of external nose, nasal cavities and olfactory apparatus and is generally associated with midline defects, microphthalmia, blepharophimosis and hypotelorism. Aesthetic problems as well as associated functional anomalies can potentially impact on the development and interpersonal relationships of the child at a later stage in life. Arhinia requires extensive management in early life in order to ensure airway patency and protection by means of tracheostomy, and to allow adequate pharyngeal and feeding function to the child. Aesthetic issues are managed with reconstructive surgery or an external prosthesis. There is no previous description in Literature of internal prosthetic devices used to sequentially shape soft tissues in complex reconstruction. We present an example of design and manufacturing of a bespoke nose implant produced by means of 3D printing and directly assessed on-table by means of 3D surface scanning.

Congenital bilateral anterior nasal atresia in 16 half-sibling Holstein-Friesian calves.

CASE REPORT: Cases of bilateral anterior nasal atresia, sometimes referred to as arhinia or partial arhinia, are extremely rare in cattle and have only been reported as single events. This report describes the birth of 16 Holstein Friesian calves over a 3-month period, all affected with bilateral atresia of the nares and anterior nasal cavity, with 2 calves having additional severe deviation of the nasomaxillary bones and nasal septum. One affected calf was born with an anatomically normal twin. Parentage testing demonstrated that a single Holstein Friesian bull sired all cases tested. CONCLUSION: This is the first report of multiple cases of bilateral anterior nasal atresia in cattle with evidence that demonstrates a heritable condition.