Two stillborn sisters had characteristics of both agnathia and holoprosencephaly. Familial occurrence implies that agnathia-holoprosencephaly may be determined by a single recessive gene, something to be taken into account when counseling such families. Evidence from human experience and various animal models suggests that agnathia-holoprosencephaly represents a causally heterogeneous single developmental field defect. Anatomical studies of these two stillborn sisters support the view that they shared a developmental field defect which affected structures in the face, cranial cavity, and upper neck. The pathogenesis of these variably expressed defects probably relates to defects in neural crest cells of cranial origin and/or to underlying mesodermal support elements of these cells.

We reviewed etiologic and phenotypic aspects of those orofacial and limb anomalies usually diagnosed as Hanhart syndrome and Mobius syndrome but also those described, among others, under names such as aglossia-adactylia syndrome, gloss-palatine ankylosis, ankyloglossia superior, peromelia and micrognathia, cleft palate/lateral synechiae syndrome, and the Charlie M. syndrome. By coding the degree of severity of the limb defects it was possible to compare these cases quantitatively and to determine the nosologic significance of associated cranial nerve palsies and chest abnormalities. We analyzed 7 personal and 62 previously reported cases and found: 1. that the severity in the upper limbs and, particularly, malformations of the feet, but not the presence or absence of cranial nerve palsies, is a significant feature in the differentiation of cases, and 2. that the group of patients with cranial nerve palsies includes some with limb defects similar to those in the Hanhart syndrome and others with features which overlap the manifestations of the Poland syndrome. Still other cases had cranial nerve palsy as an isolated trait or as a component manifestation of several different syndromes. These findings permit re-definition and nosologic delimitation of the various syndromes as follows: 1. The Hanhart-syndrome: usually severe limb defect of at least one hand or foot, frequently associated with severe oral abnormalities and sometimes also with cranial nerve palsy. Most cases reported as aglossia-adactylia syndrome, aglossia-hypomelia syndrome, and some cases reported as glossopalatine ankylosis, ankyloglossia superior and Mobius syndrome describe instances of the Hanhart syndrome. 2. The Poland-Mobius syndrome: we suggest this term to refer to those cases of "Mobius syndrome" which have a chest defect and/or symbrachydactyly of the type seen in the Poland syndrome. We suspect that these cases of the "Mobius syndrome," and most of the cases which are usually diagnosed as Poland syndrome represent a different spectrum of the same condition, hence the term Poland-Mobius syndrome. 3. The autosomal dominant cleft palate/lateral synechiae syndrome delineated by Fuhrmann et al. and other apparently less frequent conditions are mentioned in the discussion. Cranial nerve palsy obviously occurs in several etiologically distinct conditions. An analogous situation is present, although less obvious, in the Hanhart and the Poland-Mobius syndrome. Both of these conditions are formal genesis malformation syndromes which implies that they are etiologically non-specific developmental field complexes. In the Hanhart syndrome Bersu et al. postulate a common pathogenetic disturbance for oral and limb defects, thus suggesting that the manifestations represent a single anomaly rather than a "syndrome." This anomaly, for which we suggest the term Kettner anomaly, may occur not only in the Hanhart syndrome but also in other conditions. Similarly, the Poland anomaly, i.e...

The brain findings at autopsy of an 18-year-old male with FG syndrome were megalencephaly, midline fusion of mammillary bodies, heterotopia of neuroglial tissue in the 7th and 8th nerves, and ependymal cell replacement by neuroglial tissue as well as a diffuse defect of neuronal cell migration evidenced from pachygyria of many gyri, dysgenesis of cerebral cortex, and heterotopia of neurons in the white matter of the centrum ovale. A cousin, studied at 20 weeks' gestational age, had gross turridolichocephaly with enlarged cranium and also multiple minor external and internal anomalies. An affected brother of this fetus died at 17 months of complications of a congenital heart defect and CNS dysfunction. X-linked inheritance of the FG syndrome is confirmed.

We report the anatomical variations of the limbs in eight infants with the trisomy-18 syndrome that were dissected and studied in detail. In each case, the upper limbs showed defects which further define the specific influence of this aneuploidy on the development of its preaxial (radial) component, and the tendency towards reduction defects. Abnormalities included muscle variations concentrated along the radial margin of the forearm and hand, the absence of the definitive musculocutaneous nerve in all of the limbs, and reductions of the radial artery in four of the bodies. Pathogenetic mechanisms explaining the observed defects are discussed, and include: 1) a defect in peripheral nerve development; or 2) tissue necrosis. The characteristic flexion deformities of the fingers seem to be due to a displacement of the tendons of extensors digitorum and digiti minimi. The lower limbs did not show a consistent pattern of defects, except for the absence of some muscles (psoas minor, the tendon of flexor digitorum brevis to digit V), and the presence of several supernumerary muscles. These variations are discussed as possible nonspecific effects of 18-trisomy on development. The additional anatomical data from this and the first paper in this series [Bersu and Ramirez-Castro, 1977] provide a more detailed picture of the trisomy-18 phenotype which may be useful in corroborating an unconfirmed clinical diagnosis of the syndrome.

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