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.

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.
METHODS: 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.
CONCLUSIONS: 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.

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.

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 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.

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.

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 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.

OBJECTIVE: 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.
CONCLUSIONS: 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.

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.
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.
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.
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.
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.