Congenital arhinia: molecular-genetic analysis of five patients

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.

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.

Nasal Reconstruction of a Frontonasal Dysplasia via Septal L-Strut Reconstruction Using Costal Cartilage

OBJECTIVE

Frontonasal dysplasia (FND) is a rare congenital condition. Its major features include hypertelorism, a large and bifid nasal tip, and a broad nasal root. We present our technique of septal L-strut reconstruction using costal cartilage.

DESIGN

Retrospective review from June 2008 and August 2017.

METHODS

Under general anesthesia, 6 patients with FND underwent septal reconstruction using costal cartilage via open rhinoplasty. We reconstructed the nasal and septal cartilaginous framework by placing columellar struts and cantilever-type grafts.

RESULTS

The patients ranged in age from 6 to 13 years old. All were female. The follow-up period ranged from 8 months to 2 years; we encountered no postoperative complications (infection, nasal obstruction, or recurrence). All patients were satisfied with their nasal appearance.

CONCLUSIONS

Although the results were not entirely satisfactory from an esthetic point of view, we found that FND can be treated via septal reconstruction with costal cartilage and that the clinical outcomes are reliable and satisfactory. Our approach is a useful option for FND patients.

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.

Heminasal Reconstruction Utilizing Presurgical Planning, Template-Based Cartilage Reconstruction and Tissue Expansion

Heminasal aplasia is a rare congenital nasal anomaly in which there is unilateral deficiency in both the external nasal anatomy and nasal airway. Unilateral failure in development of a nasal placode in embryogenesis is thought to be the underlying cause of this anomaly. The authors describe the reconstruction of heminasal aplasia in a teenager utilizing a templated cartilaginous framework and tissue expansion. The authors feel the satisfactory results of this technique will be of benefit to other surgeons who may encounter this rare anomaly.

Congenital Heminasal Aplasia: Clinical Picture, Radiological Findings, and Follow-up After Early Surgical Intervention

OBJECTIVE

This report presents an extremely rare case of heminasal aplasia or hemi-arhinia with only about 80 cases reported so far. The exact etiology and mechanism of development of heminasal aplasia are still unknown. Furthermore, the rarity of this anomaly makes its reconstruction a surgical challenge with a diversity and controversy on the timing and technique of such reconstructive procedures.

METHOD

Reconstruction was performed when the child was 3 months of age. The missing heminose was reconstructed by a superiorly based nasolabial flap.

RESULTS

On early follow-up visits, there was retraction of the flap. However, the parents were satisfied by the result to the degree that the girl did not show for follow up after 3 years of surgery until she is 13 years and even now her parents do not want any further surgery.

CONCLUSION

Early surgical reconstruction is recommended even if revisions may be needed later.

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.

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 Pico^TM 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.

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.

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.

Prenatal diagnosis of total arhinia by MRI

Congenital arhinia is the absence of an external nose, nasal cavities and olfactory apparatus, and extremely rare. It occurs during the early gestational stage and may be a result of maldevelopment of the paired nasal placodes embryologically. Total arhinia is often associated with other craniofacial abnormalities. Early detection may be helpful for the parents and physician. However, fewer than 40 patients with arhinia have been reported so far, and most of them were diagnosed after birth. To our knowledge, this is the first case diagnosed by fetal MRI during the second trimester of pregnancy, and confirmed by pathological examination.

Heminasal agenesis: a reconstructive challenge

Heminasal agenesis is a rare congenital malformation often associated with deformities of the eyes and lacrimal system, midface, and proboscis lateralis. Reconstruction is especially challenging because of missing lining, cartilage, and skin. We present a case of heminasal agenesis in a 5-year-old girl with concomitant hypertelorism, coloboma of the eyelids, and maxillary hypoplasia. The patient underwent facial bipartition for hypertelorism correction and cantilever bone graft. A forehead flap was designed using an anaplastic model from the patient's twin sister. Cartilage harvested from the conchal bowl and rib provided alar and dorsal support. Reconstructive goals, timing, and options are discussed.

Expanding the clinical phenotype at the 3q13.31 locus with a new case of microdeletion and first characterization of the reciprocal duplication

Congenital deletions at the 3q13.31 locus have been recently described as a novel microdeletion syndrome characterized by developmental delay, postnatal overgrowth, hypoplastic male genitalia and characteristic facial features. A common critical region of overlapping of 580kb was delineated including two strong candidate genes for developmental delay: DRD3 and ZBTB20. In this report, we describe a new case of 3q13.31 microdeletion identified by array-CGH in a 16year-old girl sharing clinical features commonly observed in the 3q13.31 microdeletion syndrome. This girl had a microdeletion of 7.39Mb spanning the common critical region of overlapping. More interestingly, we report for the first time the existence of a microduplication reciprocal to the microdeletion syndrome. This familial 2.76Mb microduplication identified by array-CGH was carried by two brothers and their father. The phenotype shared by the brothers resembled the phenotype related to the 3q13.31 microdeletion syndrome including especially severe intellectual disability, developmental delay, behavioral abnormalities and obesity. This microduplication involves three strong candidate genes for the developmental delay ZBTB20, LSAMP and GAP43. Further molecular characterization showed that DRD3, another strong candidate gene for developmental delay, was not included in the duplicated region. However, a dosage alteration of this gene cannot be completely excluded as the duplication was inverted at proximity of this gene, as revealed by FISH analysis. Finally, we hypothesized that the phenotype shared by the two brothers could be related to a gene dosage imbalance even if gene expression could not be measured in relevant tissues such as brain or adipocytes.

Recurrent HERV-H-mediated 3q13.2-q13.31 deletions cause a syndrome of hypotonia and motor, language, and cognitive delays

We describe the molecular and clinical characterization of nine individuals with recurrent, 3.4-Mb, de novo deletions of 3q13.2-q13.31 detected by chromosomal microarray analysis. All individuals have hypotonia and language and motor delays; they variably express mild to moderate cognitive delays (8/9), abnormal behavior (7/9), and autism spectrum disorders (3/9). Common facial features include downslanting palpebral fissures with epicanthal folds, a slightly bulbous nose, and relative macrocephaly. Twenty-eight genes map to the deleted region, including four strong candidate genes, DRD3, ZBTB20, GAP43, and BOC, with important roles in neural and/or muscular development. Analysis of the breakpoint regions based on array data revealed directly oriented human endogenous retrovirus (HERV-H) elements of ~5 kb in size and of >95% DNA sequence identity flanking the deletion. Subsequent DNA sequencing revealed different deletion breakpoints and suggested nonallelic homologous recombination (NAHR) between HERV-H elements as a mechanism of deletion formation, analogous to HERV-I-flanked and NAHR-mediated AZFa deletions. We propose that similar HERV elements may also mediate other recurrent deletion and duplication events on a genome-wide scale. Observation of rare recurrent chromosomal events such as these deletions helps to further the understanding of mechanisms behind naturally occurring variation in the human genome and its contribution to genetic disease.

Hypogonadotropic hypogonadism presenting with arhinia: a case report

INTRODUCTION

Arhinia, congenital absence of the nose, is a rare malformation. We present the third reported case of arhinia accompanied by hypogonadism and demonstrate that this is due to gonadotropin deficiency.

CASE PRESENTATION

A 13-year-old Caucasian boy with congenital arhinia presented for evaluation of delayed puberty and micropenis. We examined genes known to be associated with hypogonadotropic hypogonadism for mutations and performed a chromosomal microarray to assess copy number variation.

CONCLUSION

No mutations in KAL1, FGFR1, PROK2, PROKR2, FGF8, CHD7 and GnRHR were identified in our patient and there were no copy number variations observed that would explain the phenotype. Though studies are limited in such patients, we suggest that hypogonadotropic hypogonadism is associated with arhinia and that the two entities likely result from a common genetic cause that affects early nasal development and gonadotropin-releasing hormone neuron formation or migration.

The role of maxillary osteotomy in the treatment of arhinia

PURPOSE

Arhinia is a very rare malformation, and only 41 cases are described in the literature. Given its rarity, there is no standardized surgical protocol. This article describes our preferred treatment, which underlines the importance of maxillary osteotomy for obtaining satisfactory results.

METHODS

We observed 3 girls with arhinia, 2 of whom were treated by a 2-step surgical protocol. During the first phase, the patients underwent maxillary osteotomy with the creation of a new epithelium-lined nasal cavity. A skin expander was also placed in the forehead. During the second step, an external nose was created in both patients from the expanded forehead flap with local perinasal flaps and costochondral grafts.

RESULTS

Both reconstructions were viable and esthetically acceptable. No internal nose restenosis was observed.

CONCLUSIONS

On the basis of our experience, maxillary osteotomy should be considered part of an integrated approach in treating arhinia.

A novel microdeletion syndrome at 3q13.31 characterised by developmental delay, postnatal overgrowth, hypoplastic male genitals, and characteristic facial features

BACKGROUND

Congenital deletions affecting 3q11q23 have rarely been reported and only five cases have been molecularly characterised. Genotype-phenotype correlation has been hampered by the variable sizes and breakpoints of the deletions. In this study, 14 novel patients with deletions in 3q11q23 were investigated and compared with 13 previously reported patients.

METHODS

Clinical data were collected from 14 novel patients that had been investigated by high resolution microarray techniques. Molecular investigation and updated clinical information of one cytogenetically previously reported patient were also included.

RESULTS

The molecular investigation identified deletions in the region 3q12.3q21.3 with different boundaries and variable sizes. The smallest studied deletion was 580 kb, located in 3q13.31. Genotype-phenotype comparison in 24 patients sharing this shortest region of overlapping deletion revealed several common major characteristics including significant developmental delay, muscular hypotonia, a high arched palate, and recognisable facial features including a short philtrum and protruding lips. Abnormal genitalia were found in the majority of males, several having micropenis. Finally, a postnatal growth pattern above the mean was apparent. The 580 kb deleted region includes five RefSeq genes and two of them are strong candidate genes for the developmental delay: DRD3 and ZBTB20.

CONCLUSION

A newly recognised 3q13.31 microdeletion syndrome is delineated which is of diagnostic and prognostic value. Furthermore, two genes are suggested to be responsible for the main phenotype.

Congenital arhinia: A rare case

Congenital arhinia or absence of nose is a rare condition with only 30 cases reported so far. We report a rare case and briefly review the literature.

Management of a case of arhinia

Arhinia is a rare condition characterised by the congenital absence of nasal structures, with different patterns of presentation, and often associated with other craniofacial or somatic anomalies. To date, about 30 surviving cases have been reported. We report the case of a female patient aged 6 years, who underwent internal and external nose reconstruction using a staged procedure: a nasal airway was obtained through maxillary osteotomy and ostectomy, and lined with a local skin flap and split-thickness skin grafts; then the external nose was reconstructed with an expanded frontal flap, armed with an autogenous rib framework.

A genomewide linkage scan for quantitative trait loci influencing the craniofacial complex in baboons (Papio hamadryas spp.)

Numerous studies have detected significant contributions of genes to variation in development, size, and shape of craniofacial traits in a number of vertebrate taxa. This study examines 43 quantitative traits derived from lateral cephalographs of 830 baboons (Papio hamadryas) from the pedigreed population housed at the Southwest National Primate Research Center. Quantitative genetic analyses were conducted using the SOLAR analytic platform, a maximum-likelihood variance components method that incorporates all familial information for parameter estimation. Heritability estimates were significant and of moderate to high magnitude for all craniofacial traits. Additionally, 14 significant quantitative trait loci (QTL) were identified for 12 traits from the three developmental components (basicranium, splanchnocranium, and neurocranium) of the craniofacial complex. These QTL were found on baboon chromosomes (and human orthologs) PHA1 (HSA1), PHA 2 (HSA3), PHA4 (HSA6), PHA11 (HSA12), PHA13 (HSA2), PHA16 (HSA17), and PHA17 (HSA13) (PHA, P. hamadryas; HSA, Homo sapiens). This study of the genetic architecture of the craniofacial complex in baboons provides the groundwork needed to establish the baboon as an animal model for the study of genetic and nongenetic influences on craniofacial variation.