Hypogonadotropic hypogonadism presenting with arhinia: a case report

Clinical report of Bosma arhinia microphthalmia syndrome with a new variant on SMCHD1 gene. A case report

The Bosma syndrome (BAMS: Bosma arhinia microphthalmia syndrome) is a condition first described in 1972. Since then, several reviews have published the cases looking for diagnostic criteria and associated genetic alterations. The mutation in the SMCHD1 gene (Structural Maintenance of Chromosomes flexible Hinge Domain containing protein 1) seems to explain a part of the development of the phenotype. Not all cases show the same alterations or meet the classic diagnostic criteria, and few have undergone genetic analysis. We present a case with a new variant in this gene and an update of the literature on this syndrome with the aim of improving the diagnosis and follow-up of these patients.

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.

Reconstruction of Congenital Arhinia With Stereolithographic Modeling: Case Correlate and Literature Review

Complete congenital arhinia is a rare defect of embryogenesis leading to the absence of the external nose and airway. We report our novel multistaged reconstructive approach and literature review. Nasal methyl methacrylate prosthesis was created from a stereolithographic model for use as a temporary prosthesis and tissue expander. Lefort 1 with cannulization was utilized for midface advancement and airway formation. External framework was reconstructed with bilateral conchal bowl cartilage and rib osteocartilagenous grafts. Patient was pleased with the aesthetics and had safe decannulation with the ability to breathe through the nose and airway.

Congenital arrhinia: A case report and literature review

INTRODUCTION

Underdevelopment of the nose is a wide spectrum entity ranges from partial absence of the nose to congenital arrhinia (CA). CA is the congenital absence of the external nose, nasal cavities, and/or nasal nostrils±olfactory apparatus, and is an extremely rare entity as less than 50 cases reported in the literature. CA can be isolated and idiopathic in origin or be a part of genetic-linked certain syndromes. Of note, the isolated CA can be inherited as an autosomal dominant condition with incomplete penetrance.

PRESENTATION OF CASE

We report a 13-month-old Palestinian female patient with isolated CA complicated with recurrent lower and upper respiratory tract infections (URTI). The family history is significant for the mother with incomplete and uncomplicated underdevelopment of the external nose and nasal nostrils. The patient uses a tracheostomy to breathe and is waiting for the optimal age for surgical correction. In addition, we reviewed the available literature using PubMed and summarized all CA cases reported from 2016 to 2019 since two studies had presented the literature before 2016, and presented them in a very comprehensive table.

DISCUSSION

CA is largely idiopathic and not well understood. Although CA can be inherited and runs in families with incomplete penetrance, no causative genetic abnormalities had been found in most of the reported cases. CA frequently presents with upper airway obstruction and respiratory distress, recurrent lower and URTI, and feeding difficulties. CA is managed initially with tracheostomy and should be followed by a surgical correction at the appropriate age.

CONCLUSION

CA may be sporadic, familial, or a part of a syndrome. CA carries a significant rate of morbidity and mortality and a tracheostomy should be inserted initially to alleviate the early CA complications and followed by surgical reconstruction when the patient reaches the age of preschool/school age. More studies are required to determine CA inheritance.

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.

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.

De novo mutations in SMCHD1 cause Bosma arhinia microphthalmia syndrome and abrogate nasal development

Bosma arhinia microphthalmia syndrome (BAMS) is an extremely rare and striking condition characterized by complete absence of the nose with or without ocular defects. We report here that missense mutations in the epigenetic regulator SMCHD1 mapping to the extended ATPase domain of the encoded protein cause BAMS in all 14 cases studied. All mutations were de novo where parental DNA was available. Biochemical tests and in vivo assays in Xenopus laevis embryos suggest that these mutations may behave as gain-of-function alleles. This finding is in contrast to the loss-of-function mutations in SMCHD1 that have been associated with facioscapulohumeral muscular dystrophy (FSHD) type 2. Our results establish SMCHD1 as a key player in nasal development and provide biochemical insight into its enzymatic function that may be exploited for development of therapeutics for FSHD.

Hypogonadotropic hypogonadism in a female patient with congenital arhinia

The association of anosmia and congenital hypogonadotropic hypogonadism (CHH) is well described; however, congenital arhinia is a malformation associated with CHH that occurs much more rarely. There have been three reports of male patients with hypogonadism and congenital arhinia in the literature to date. We present the first case of arhinia associated with CHH in a female patient. A 14 years and 8 months female with congenital arhinia presented with delayed puberty. Physical examination and laboratory evaluation were consistent with hypogonadotropic hypogonadism. She had no other hormone deficiencies and brain magnetic resonance imaging demonstrated a normal pituitary gland. Abdominal ultrasound showed a prepubertal uterus and ovaries. She was subsequently started on sex steroid treatment to induce secondary sexual characteristics. This case demonstrates that abnormalities of nasal development may provide an early diagnostic clue to hypogonadotropic hypogonadism, particularly in female patients who would not manifest classic signs of CHH in infancy (micropenis and cryptorchidism). Early diagnosis of CHH and timely initiation of sex steroid therapy is important to prevent comorbidities related to pubertal delay.

Bosma arrhinia microphthalmia syndrome in a Mexican patient with a molecular analysis of PAX6

The association of anophthalmia, arrhinia, and hypogonadism constitutes the major clinical features for Bosma arrhinia microphthalmia syndrome. However, there is variability in the presentation of this disease; arrhinia is the most constant clinical feature, which is then combined with a spectrum of anophthalmia/microphthalmia and/or hypogonadism. This rare entity is not associated with any specific genes, but the genes that are related to arrhinia and anophthalmia have been studied in an attempt to explain this phenomenon. We analyzed the PAX6 gene in a Bosma arrhinia microphthalmia syndrome patient but found no variation or mutation that could constitute or establish a causal association in our patient.

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.