Branchial Cleft Anomalies: Embryogenesis, Clinical Features, Diagnosis, and Management

Branchial cleft anomalies are congenital head and neck lesions that arise from incomplete maturation of the branchial apparatus during fetal development. The branchial arches are the precursors of the face, neck and pharynx, and disturbances in embryogenesis can present clinically as cysts, sinus tracts, and fistulas in predictable anatomic locations. However, there remains controversy regarding the precise embryogenesis of branchial cleft anomalies with several competing theories. These lesions often evade diagnosis in early childhood and may present in a delayed fashion after multiple failed interventions. Various diagnostic modalities have been described to facilitate clinical workup. Definitive treatment is complete surgical excision of the lesion. We present a comprehensive review of the literature along with several illustrative cases that highlight the unique challenges of diagnosis and surgical management of branchial cleft anomalies.

THE CLINICAL CASE OF HEMIFACIAL MICROSOMIA IN THE NEWBORN BOY FROM MOTHER WITH Z-21

Hemifacial Microsomia (HFM) is a term used to identify facial deformities associated with the development ofthe first and second pairs of branchial arches, characterized by underdevelopment of one half of the face. One typeof hemifacial microsomia is oculo-auriculo-vertebral dysplasia or Goldenhar syndrome.The incidence of HFM is 1:3500-1:7000 of live births and occurs in 1 case per 1000 children with congenitaldeafness. The ratio of boys to girls is 3:2. The etiology and type of inheritance is studied insufficiently. There are threepossible pathogenetic models: vascular abnormalities and hemorrhages in the craniofacial region, damage of Meckel'scartilage, and abnormal cell development of the cranial nerve crest. Environmental factors, maternal internal factors,and genetic factors (OTX2, PLCD3, and MYT1 mutations) may also cause the development of hemifacial microsomia.The article demonstrates a clinical case of hemifacial microsomia in a newborn boy from a mother with Z-21 inthe form of deformation of the left auricle with atresia of the auditory canal and "false" ears on the right, combinedwith congenital anomaly of heart (atrial septal defect) and brain (hypoplasia of the corpus callosum).Emphasis is placed on the need of involving a multidisciplinary team of specialists in the management of thispatient both in the neonatal period and in the system of subsequent follow-up.

Auricular Prosthesis for Congenitally Deformed Ear with Acrylic Template for Colour Depiction - A Case Report

Prosthodontists usually stick to the dictum by MM Devan, “preservation of what remains than meticulous replacement of what has been lost.1” “Microtia” is a term used to describe congenital anomaly of the external ear. It is a combination of the words “micro” and “otia” each of the term denoting small and ear respectively. It includes a range of deformities which may consist of presence of a rudimentary ear, a grossly normal or smaller ear or complete absence of the entire external ear. These deformities usually account for 3 in every ten thousand births, with less than 10 % of all the cases showing bilaterally missing ears.2-4 Facial deformities are common for the microtia patient as the auricle develops from tissues of the branchial arches. Figure 1 describes the patient having congenitally missing unilateral ear. Maxillofacial prosthodontics deals with prosthetic rehabilitation of disfigured or missing parts of head and neck. Prosthetic replacement of the exterior part (Epithesis) can be related to as old as civilization. References to it are available in Indian, Greek, Roman, Egyptian Civilizations.5 Ambroise Pare is credited with making various contributions to the materials and techniques in facial prosthetics. Fabrication of an extra-oral prosthesis is probably more of an art than science. Throughout the recorded history, humans have attempted to restore missing parts of the body by using various artificial materials. MPF materials have evolved since centuries right from metals, ivory, porcelain, waxes, natural rubber, gelatin, and latex to modern day materials such as methacrylate or acrylic resins, polyurethane elastomers, and silicone elastomers each having their own set of advantages and disadvantages. But silicone is most commonly used because of its assorted benefits over other MFP materials. This case report describes an auricular prosthesis for the patient with congenital ear deformity using an acrylic template for colour depiction and room temperature volcanizing (RTV) silicone.6

Apert Syndrome: A Rare Genetic Disorder

Apert syndrome is a rare type I acrocephalosyndactyly syndrome having autosomal dominant inheritance due to mutations in the fibroblast growth factor receptors gene. New or fresh mutations are also frequent. It is characterized by dysmorphic face, craniosynostosis, severe syndactyly of the hands and feet. Apert syndrome affects the first branchial or pharyngeal arch, the precursor of the maxilla and mandible. Disturbances in the development of branchial arches during fetal period create extensive malformation in different parts of the body. Management of Apert syndrome requires a multidisciplinary approach. We, hereby, report a case of a 45-days old baby with Apert syndrome. Northern International Medical College Journal Vol.11 (2) Jan 2020: 475-477

Influence of temperature on larval ontogenesis of Geophagus brasiliensis (Quoy & Gaimard, 1824) (Pisces: Cichlidae)

Summary Studies on the larval development of fish are essential for conservation and improvements in cultivation techniques. Geophagus brasiliensis popularly known as Cará has potential as a fish of interest in ornamental aquaculture. Wild adults of G. brasiliensis were kept in an aquarium for spontaneous reproduction. Newly hatched larvae were transferred to 5-litre aquaria at 22, 26 and 30°C until total yolk sac resorption. Histological slides were used for biometric analysis and monitoring of larval ontogenesis at different temperatures. Histologically, from the first to the fourth days it was possible to identify myomeres, optic vesicle, yolk syncytial layer, brain, heart and differentiation of the eye layers. From the fourth to the seventh days, it was possible to identify mandibular and gill cartilages, swim bladder, liver, prismatic epithelium with striated border in intestine and renal epithelium. All biometric measurements increased over the days, except height and length of the yolk sac, which gradually decreased until the complete resorption of the yolk sac that occurred on the fifth day at a temperature of 30°C, the sixth day at 26°C and the seventh day at 22°C. Morphological events at 30°C such as the reabsorption of the yolk sac, the appearance of cartilage in the branchial arches and differentiation of the layers of the eyes occurred faster compared with the other temperatures tested. Opening of the mouth and digestive tract occurred at a similar time on the fourth day in all temperatures.

Hmx1 regulates urfh1 expression in the craniofacial region in zebrafish

H6 family homeobox 1 (HMX1) regulates multiple aspects of craniofacial development as it is widely expressed in the eye, peripheral ganglia and branchial arches. Mutations in HMX1 are linked to an ocular defect termed Oculo-auricular syndrome of Schorderet-Munier-Franceschetti (MIM #612109). We identified UHRF1 as a target of HMX1 during development. UHRF1 and its partner proteins actively regulate chromatin modifications and cellular proliferation. Luciferase assays and in situ hybridization analyses showed that HMX1 exerts a transcriptional inhibitory effect on UHRF1 and a modification of its expression pattern. Overexpression of hmx1 in hsp70-hmx1 zebrafish increased uhrf1 expression in the cranial region, while mutations in the hmx1 dimerization domains reduced uhrf1 expression. Moreover, the expression level of uhrf1 and its partner dnmt1 was increased in the eye field in response to hmx1 overexpression. These results indicate that hmx1 regulates uhrf1 expression and, potentially through regulating the expression of factors involved in DNA methylation, contribute to the development of the craniofacial region of zebrafish.

Hemifacial Microsomia (HFM) and Treacher Collins Syndrome

Hemifacial microsomia and Treacher Collins syndrome are two entities which arise as a consequence of abnormal development of first and second branchial arches in utero. As a result, these dentofacial deformities present with abnormal facies especially the maxilla and mandible. They may also occur as part of other syndromes and may involve other structures of the body. In this chapter, we have discussed the etiology, clinical features, radiological assessment and treatment planning of such cases. Special emphasis should be made on early diagnosis, challenges of airway management and feeding and parental counselling. Since the two deformities are largely considered to be non-progressive, early distraction plays an important role in correction of the dentofacial deformity in these patients.

The CXCR4/SDF-1 Axis in the Development of Facial Expression and Non-somitic Neck Muscles

Trunk and head muscles originate from distinct embryonic regions: while the trunk muscles derive from the paraxial mesoderm that becomes segmented into somites, the majority of head muscles develops from the unsegmented cranial paraxial mesoderm. Differences in the molecular control of trunk versus head and neck muscles have been discovered about 25 years ago; interestingly, differences in satellite cell subpopulations were also described more recently. Specifically, the satellite cells of the facial expression muscles share properties with heart muscle. In adult vertebrates, neck muscles span the transition zone between head and trunk. Mastication and facial expression muscles derive from the mesodermal progenitor cells that are located in the first and second branchial arches, respectively. The cucullaris muscle (non-somitic neck muscle) originates from the posterior-most branchial arches. Like other subclasses within the chemokines and chemokine receptors, CXCR4 and SDF-1 play essential roles in the migration of cells within a number of various tissues during development. CXCR4 as receptor together with its ligand SDF-1 have mainly been described to regulate the migration of the trunk muscle progenitor cells. This review first underlines our recent understanding of the development of the facial expression (second arch-derived) muscles, focusing on new insights into the migration event and how this embryonic process is different from the development of mastication (first arch-derived) muscles. Other muscles associated with the head, such as non-somitic neck muscles derived from muscle progenitor cells located in the posterior branchial arches, are also in the focus of this review. Implications on human muscle dystrophies affecting the muscles of face and neck are also discussed.

PROSTHETIC TREATMENT OF A PATIENT WITH NAGERACROFACIALDYSOSTOSIS: A CASE REPORT

Introduction: Nager syndrome, alsoknown as Nager acrofacialdysostosis, was first described by Nager and de Reynierin 1948. It is a rare syndrome resultingfromdevelopmentalabnormalities of the first and second branchial arches and ismostlysporadic. The prevalenceisunknown about 100 cases have been published up to now. The purpose of this report is to present a case of Nager syndrome wherewewere able to achieve a conventionalcomplete denture despite the many challenges due to the complexity of the clinical case. Case Report: A 27-years-old female patient wasreferred to our service of RemovableProsthodontics at Casablanca UniversityHospital Center complaining of difficulty in speaking and chewing. The patient presentedseveralcraniofacial anomalies including facial atrophy, maxillomandibularhypoplasia, flat nasal bridge, associated to defectsupper and lowerlimbs. Based on these craniofacial characteristics and the coexistingupper and lowerlimbpreaxial anomalies, a diagnosis of Nager syndrome wasconfirmed.The intra-oral examinationrevealed an edentulous mandibular arch and carious, mobile and hypomineralizedmaxillaryteeth, the patient presents a severemicrognatiawith a skeletal Cl III whichcomplicates the prosthetic management of the patient. Therealization of a complete denture has improved the comfort and function of the patient. Conclusion: Nager Syndrome is a condition with a ratherheavyclinical situation and its management must bemultidisciplinary, the psychology and comfort of these patients isoftenaffected. Oral care has improvedaesthetics, function and the quality of life in this patient with Nager syndrome.

Sequence analysis and spatiotemporal developmental distribution of the Cat-1-type transporter slc7a1a in zebrafish (Danio rerio)

Cationic amino acid transporter 1 (Cat-1 alias Slc7a1) is a Na+-independent carrier system involved in transport and absorption of the cationic amino acids lysine, arginine, histidine, and ornithine and has also been shown to be indispensable in a large variety of biological processes. Starting from isolated full-length zebrafish (Danio rerio) cDNA for slc7a1a, we performed comparative and phylogenetic sequence analysis, investigated the conservation of the gene during vertebrate evolution, and defined tissue expression during zebrafish development. Whole mount in situ hybridization first detected slc7a1a transcripts in somites, eyes, and brain at 14 h post-fertilization (hpf) with additional expression in the distal nephron at 24 hpf and in branchial arches at 3 days post-fertilization (dpf), with significant increase by 5 dpf. Taken together, the expression analysis of the zebrafish Cat-1 system gene slc7a1a suggests a functional role(s) during the early development of the central nervous system, muscle, gills, and kidney.