A newborn lethal defect due to inactivation of retinaldehyde dehydrogenase type 3 is prevented by maternal retinoic acid treatment

The retinoic acid (RA) signal, produced locally from vitamin A by retinaldehyde dehydrogenase (Raldh) and transduced by the nuclear receptors for retinoids (RA receptor and 9-cis-RA receptor), is indispensable for ontogenesis and homeostasis of numerous tissues. We demonstrate that Raldh3 knockout in mouse suppresses RA synthesis and causes malformations restricted to ocular and nasal regions, which are similar to those observed in vitamin A-deficient fetuses and/or in retinoid receptor mutants. Raldh3 knockout notably causes choanal atresia (CA), which is responsible for respiratory distress and death of Raldh3-null mutants at birth. CA is due to persistence of nasal fins, whose rupture normally allows the communication between nasal and oral cavities. This malformation, which is similar to isolated congenital CA in humans and may result from impaired RA-controlled down-regulation of Fgf8 expression in nasal fins, can be prevented by a simple maternal treatment with RA.

Choanal atresia, CHARGE association, and congenital nasal stenosis

Congenital bilateral narrowing or obstruction of the nasal airway can result in significant respiratory distress in the neonate, requiring emergency intervention. Some of these children have associated congenital malformations that may also impact on the management of the nasal anomaly. The embryology, presentation, and management of this spectrum of disorders are discussed, and the major surgical controversies are reviewed.

Bilateral choanal atresia associated with malformation of the anterior skull base: embryogenesis and clinical implications

A number of craniofacial and systemic malformations have been described in association with choanal atresia. We report a case of bilateral choanal atresia associated with congenital absence of the cribriform plate, crista galli, and perpendicular plate of the ethmoid bone. The anterior skull base defect was detected by using high-resolution computed tomography with three-dimensional reconstructions. The findings support the mesodermal flow theory of choanal atresia, in which there is excess migration of neural crest cells into the developing nasal septum and posterior choanae. This occurs at the expense of cells that would otherwise form the rest of the ethmoid complex. Clinical implications include the need for adequate preoperative imaging of the anterior skull base and consideration of potential intracranial complications during surgical repair.

Kallmann syndrome associated with choanal atresia

Kallmann syndrome is defined by the association of hypogonadotropic hypogonadism and anosmia. A previously unreported association of Kallmann syndrome and choanal atresia in a family is reported. The mechanism of the embryopathic association of hypogonadotropic hypogonadism, anosmia, and choanal atresia is though to be due to a single developmental field defect in the region of the median forebrain and associated structures. An irregular autosomal dominant mode of inheritance is suspected.

Maturational dysautonomia and facial anomalies associated with esophageal atresia: support for neural crest involvement

Patients with esophageal atresia (EA) or choanal atresia/stenosis (CA) present with many clinical features of maturational dysautonomia (DY). Since CA and DY are considered manifestations of cephalic neurocristopathy, we tested the hypothesis that EA may also be related to faulty development of cephalic neural crest. Forty-eight patients with EA and 53 with CA were followed up to study the frequency of the facial anomalies which are regarded as the phenotypic expression of an abnormal cephalic neural crest contribution to facial embryogenesis. Forty-eight patients with EA and 51 with CA had clinical manifestations of DY. Forty-four patients with EA (91%) and 49 with CA (92%) had one or more facial anomalies. Comparing the groups, patients with EA had an increased frequency of unilateral facial anomalies of branchial arch derivatives (P < .01); those with CA had an increased frequency of anomalies of frontonasal process derivatives (P < .01). These findings support the hypothesis that EA may be related to an abnormal contribution from the cephalic neural crest. The presence of facial anomalies may facilitate the diagnosis of subclinical DY.

Agnathia (severe micrognathia), aglossia and choanal atresia in an infant

A neonate is reported here, who was born with severe mandibular hypoplasia, complete absence of the tongue, unilateral choanal atresia, contralateral choanal stenosis and developed severe airway obstruction at birth. Arrested development of the ventral first branchial arch most likely underlies the clinical deficits. Most reported cases of agnathia have been lethal but the infant reported here has survived into infancy with a tracheostomy and feeding gastrostomy. Her clinical features, assessment and management are discussed.

Experience with bilateral congenital atresia of the posterior nasal choanae

Atresia of the posterior nasal choanae is an unusual congenital condition. The embryological explanation is uncertain, that felt to be the most probable being presented here. Bilateral choanal atresia tends to be associated with neonatal airways obstruction and steps to be taken in its diagnosis and management are outlined. The definitive treatment of the condition is surgical excision, by either a trans-nasal or a trans-palatal approach. The conclusions arrived at as to the most effective method of management of these cases from a personal series of fourteen cases are detailed. A preference for the trans-nasal surgical approach is indicated and surgical details for this method are given, some aspects of which have not been previously reported.

Early Transient Prenatal Ultrasound Features of Choanal Atresia

We present a case series of early second-trimester prenatal ultrasound (US) features in 4 fetuses with a confirmed diagnosis of choanal atresia. The clinical characteristics and outcomes evaluated included prenatal US findings, genetic analyses, postmortem autopsies (2 cases), and computed tomographic findings. A transient large nasal cavity was detected by US in all 4 fetuses. This finding disappeared a few weeks later. Three cases were unilateral choanal atresia, and 1 was bilateral. Transient enlargement of the nasal cavity in early pregnancy appears to be a US sign of choanal atresia.

The external rhinoplasty for the correction of unilateral choanal atresia in young children

The external rhinoplasty approach has been utilized in three young children for the correction of unilateral choanal atresia. It has been demonstrated to be technically feasible to utilize this technique in young children. It provides excellent exposure of the atresia plate with the ability to correct the atresia in a precise and confident way. This technique is an elegant alternative to transnasal puncture and transeptal resection.

[Unilateral choanal atresia and paranasal sinus growth]

Mechanisms regulating sinus growth are poorly understood. We report a series of six cases of unilateral choanal atresia and discuss the role of nasal ventilation on sinus growth. The presence and the size of the sinus cavities are the main parameters. Our preliminary results suggest that sinus growth is independent of nasal ventilation.