Three Demonstrations ON CONGENITAL MELFORMATIONS OF PALATE, FACE, AND NECK: Given at the Royal College of Surgeons, England

Holoprosencephaly and agnathia spectrum: Presentation of two new patients and review of the literature

Holoprosencephaly (HPE), the most common developmental disorder of the human forebrain, is occasionally associated with the spectrum of agnathia, or virtual absence of the mandible. This condition results in a constellation of structural cerebral and craniofacial abnormalities. Here we present two new patients and review 30 patients from the literature with HPE and variants of agnathia. The majority of these patients are female and have the most severe forms of HPE, with cyclopia present more frequently than is usually observed in cohorts of patients with HPE. Also, many patients have additional clinical findings not typical in patients with classic HPE, particularly situs abnormalities. Recent animal studies suggest that the association of HPE and agnathia may relate to alterations in signaling from forebrain and foregut endoderm organizing centers and subsequent first pharyngeal arch development, although present models are inadequate to explain all of the clinical findings of this enigmatic human syndrome. Further research is required to better elucidate the causal and pathogenic basis of this association.

Median cleft of the lower lip and mandible: case reports, a new embryologic hypothesis, and subdivision

Median clefts of the lower lip and mandible are rare. In the literature so far, about 62 cases have been described. In addition, three more patients are presented here. These cases show a broad variation in the severity of this deformity, ranging from a simple notch in the vermillion to a complete cleft of the lip involving the tongue, the chin, the mandible, the supporting structures of the median of the neck, and the manubrium sterni. Several hypotheses concerning the pathogenesis of median clefts of the lip and mandible have been proposed. Most authors consider it to be a failure of fusion of the first pair of branchial arches or failure of mesodermal penetration into the midline. From our embryologic point of view, however, instead of paired branchial arches, only one first branchial arch develops during the early embryonic period (< or = 17 mm crown-rump length). Within this first branchial arch, two mandibular processes grow out, separated by a groove in the median. These mandibular processes do not fuse but merge during the late embryonic period (> or = 17 mm to < or = 60 mm crown-rump length). In the same developmental period, there is formation of the lip and the alveolar process and the anlage and outgrowth of one membrane bone center in each mandibular process, resulting in the formation of the mandible with its symphysis. As a consequence of the preceding, we propose the following subdivision of the median clefts of the lip and/or mandible: Hypoplasia of the mandibular processes during the early embryonic period will lead to the severest cleft of the mandible extending into the neck. During the late embryonic period, the less severe median clefts will develop. Disturbances of the outgrowth of bone centers of the mandible, resulting in nonformation of its symphysis, cause clefting of the mandible with involvement of all related soft tissues. Defects in the merging process produce just a notch of the vermilion or a higher cleft of the lower lip with or without involvement of the alveolar process of the mandible. In conclusion, the variety of the clefts in the median of the lower lip and/or mandible as well as the low rate of incidence can be explained by the embryologic hypothesis proposed here.

A case of agnathia, situs inversus, and a normal central nervous system

We report here a premature female infant with agnathia, low-set but normally formed ears, a downward eye slant, choanal atresia and a cleft palate. She had severe respiratory distress and died despite maximum intervention at 5 days of age. Autopsy revealed situs inversus totalis; crossed fused renal ectopia; agnathia; normal thyroid, larynx, trachea, and bronchi; incomplete lobation of the lungs; immature pulmonary development with early hyaline membranes; and a normal central nervous system. This lack of significant central nervous system abnormalities distinguishes this infant from the majority of previously reported infants with agnathia and situs inversus.

A long surviving case of holoprosencephaly agnathia series

The rare syndrome of the agnathia with microstomia, aglossia, synotia (the external ears approaching one another in the midline) and brain malformation (agnathia-holoprosencephaly) was reported by Pauli et al. (1983) as a developmental field defect. This syndrome has two subgroups. One is more severe with brain malformation (holoprosencephaly), and the other is less severe without brain malformation. This report presents a long surviving case of this syndrome without brain malformation.

Agnathia, holoprosencephaly, and situs inversus: report of a case

We present the first documented case of agnathia-holoprosencephaly (an uncommon form of craniofacial anomaly) associated with situs inversus. This case may represent the concordance of multiple field complex anomalies, but the possibility of a major midline malformation (situs inversus) caused by a timed insult (environmental or genetic) which affects multiple structures and occurs concurrently with a major field defect during early embryogenesis cannot be excluded.

An anatomical study of human otocephaly

This study describes the gross anatomic variations observed in a 32-week male fetus diagnosed as having otocephaly. Special attention was given to the muscular, peripheral nervous, and vascular systems of the entire body. External features included approximation of the ears on the front of the neck, underdevelopment of the lower jaw, and a small oral cavity. The mandible, maxillae, and zygomatic bones were smaller than normal and appeared shifted in a ventrocaudal direction. The middle ear ossicles were fused and abnormally positioned. The tongue was positioned abnormally and malformed. The muscles of mastication were fused in the midline and formed the floor of the oral cavity. The variations were similar to the spectrum of abnormalities reported in two cases in the literature. Because of this finding, it is possible that the causative events leading to these deviations were similar in the three cases. Possible mechanisms are considered which could lead to the observed malformations seen in these cases. There were also several muscle and nerve anomalies outside of the head region.