Lymphagiomas of the alveolar ridges in neonates.

Blue-domed, fluid-filled lesions on the alveolar ridges of neonates were noted in 3.7% of all normal black newborns examined. None were found in whites. On microscopic examination of eight such lesions, the diagnosis of lymphangioma was made. These lymphangiomas should not be confused with Epstein's pearls, Bohn's nodules, eruption cysts, or mucous retention phenomena. The natural history of such lymphagiomas is unknown. However, spontaneous regression was noted in several cases.

The conditions manifesting taurodontism.

Taurodontism is a trait that has captured the interests of evolutionists and clinical geneticists. This paper reviews the reported cases of taurodontism as an isolated trait and as a component of malformation syndromes. Because of the nature of the syndromes with which it is associated and its frequency in the general population, it is concluded that taurodontism is the result of an ectodermal defect and may be useful as an indicator of development instability.

Possible second case of tricho-oculo-dermo-vertebral (Alves) syndrome.

We report on a 10-year-old girl with trichodysplasia, onychodysplasia, hyperpigmented ichthyoform lesions on her shins, mild enamel dysplasia, and hyperkeratosis involving the soles. This combination of ectodermal defects has only been described by Alves et al.

Brief clinical report: Curry-Hall syndrome.

Curry and Hall [1979] described a large Spanish-Mexican family with a pleiotropic autosomal dominant disorder of polydactyly, conical teeth, nail dysplasia, and short limbs. We describe a patient with similar manifestations, but from a different geographic and ethnic background. We propose that the disorder be called the Curry-Hall syndrome.

Brachydactyly, mesomelia, mental retardation, aortic dilatation, mitral valve prolapse, and characteristic face.

We report on a male with brachydactyly, thin habitus with narrow shoulders, mesomelic shortness of the arms, long lower face with obtuse mandibular angle, maxillary hypoplasia with beaking of the nose, aortic root dilatation, and mitral valve prolapse. This combination of findings has not been reported previously.

The Rieger syndrome.

Fourteen patients with hypodontia and the ocular features of the Rieger syndrome were examined for the presence of systemic anomalies. A periumbilical defect that consisted of failure of the periumbilical skin to involute was seen in ten of the thirteen evaluated for the defect. Three others had scars over the umbilical area and had a history of surgery for herniation. In addition, four males in one family and one male from another family had hypospadias. None of several other anomalies reported to be components of the Rieger syndrome by other authors was detected in the fourteen patients. The mode of inheritance in the familial cases studied was compatible with autosomal dominance. The results of this study indicate that the Rieger syndrome is an autosomal dominant syndrome whose cardinal features are hypodontia, goniodysgenesis, and failure of the periumbilical skin to involute properly.

A high frequency of structural chromosome abnormalities in a south central texas cytogenetics laboratory.

Abnormalities of chromosome number, such as the autosomal trisomies and sex chromosome aneuploidies, are considered to be sporadic events with low and constant recurrence risk across populations. On the other hand, abnormalities of chromosome structure can be generated by environmental agents and also transmitted in families and therefore may accumulate in certain populations. Evidence from several geographically diverse newborn infant screening studies and from clinical cytogenetics laboratories (including our own) supports the hypothesis that the frequency of structural abnormalities varies among populations, whereas the frequency of numerical abnormalities remains relatively constant among populations. The data from our laboratory, based on 1,201 patients over a 6-year period, suggest a two- to nearly fourfold higher frequency of structural defects over that of other populations (8.8% vs 4.2% and 2.5% of samples tested). Some of the problems associated with making comparisons among the published data sets are discussed, along with alternative explanations for the variability in the frequency of structural defects reported in different populations.

Tricho-dento-osseous syndrome: heterogeneity or clinical variability.

Tricho-dento-osseous (TDO) syndrome is an autosomal dominant disorder characterized by abnormalities of hair, teeth, and bone. We report on a family that seems to illustrate further clinical heterogeneity in the TDO syndrome. Although variable expression of a single TDO gene cannot be ruled out, the manifestations observed in this and other reported families appear to fall into distinct subtypes. This suggests the possibility that the clinical subtypes represent distinct genetic entities.

Deletions of the long arm of chromosome 10.

Patients with a partial deletion of the long arm of chromosome 10 are rare. We report eight new cases involving various segments of 10q: one terminal deletion (10q26), four (8;10) translocations resulting in terminal deletions (10q26) and duplications (8q24.3), a de novo interstitial deletion (10q23), an interstitial deletion due to a (10;13) translocation (10q11.2----10q22.1), and a ring (10p15----10q26).

White sponge nevus.

White sponge nevus (WSN) is one of a number of white lesions of the oral mucosa. It is an autosomal dominant disorder of wide variability and high penetrance. White sponge nevus is characterized by white, spongy lesions of the oral mucosa, although extraoral mucosae may also be affected. Onset is early in life, and both sexes are affected equally. There are no extramucosal lesions associated with WSN. The plaques of WSN are benign and may undergo alternate periods of remission and exacerbation. In two of our cases from an affected family, penicillin precipitated remission of the plaques.

Clinician's view of hypodontia.

Hypodontia, agenesis of one or more teeth, is a common trait in modern populations and one that is often encountered by the dental practitioner. Specific patterns of the trait suggest its association with extraoral findings and may help to identify the etiology.

Review of ectodermal dysplasias for nurses.

The purpose of this continuing education feature is to introduce nurses to a group of disorders called ectodermal dysplasias. The ectodermal dysplasias are genetic disorders that affect individuals from all ethnic groups. Most of the features of ectodermal dysplasias can be evaluated easily and useful information can be given to affected individuals and their families about the disorder and readily available treatment.

The role of the dentist in genetic counseling.

Professional and lay attitudes about the role of the dentist in the health sciences is changing perceptibly [16-18]. The view that the activities of the dentist are limited to manipulations of the teeth is being replaced by the view that the dentist is an important member of the health team. To be sure, medical colleagues may still ask why a dentist is in the nursery or elsewhere in the hospital and for the lay public may still ask what genetics has to do with dentistry or vice versa. But "the times, they are a-changing." There is an expanded responsibility for dentists in today's world and a significant part of that responsibility involves the provision of genetic services: diagnosis and counseling. There is no doubt in my mind that the following statement that I make to medical students and colleagues is as true for dentists as for physicians: the failure to provide genetic counseling when it is indicated is malpractice.

Everyone's guide to the dentition.

There are soft and hard tissues of the oral cavity that may develop abnormally as isolated defects or as components of syndromes. It is important for the dentist and nondentist to describe abnormalities of the oral structures since diagnosis may depend on which structure is defective and in what way. In order to describe the abnormalities, however, proper terminology must be known, and the natural state of the structures must be known. This paper describes most of the clinically relevant oral structures in reasonable terminology and sets the stage for the specialized papers that follow.

Problems in nomenclature of craniofacial disorders.

The diverse background of clinical geneticists may lead to problems of communication unless attention is paid to nomenclature. In this paper, consensus is sought on terms for normal and abnormal development, a system for labeling developmental defects of dentin is proposed, and terms for patterns of coexistent variations are defined. The major methods for naming coexistent variations are reviewed, with attention to the disadvantages of each. An informal study on recognition of patterns of variation based on the naming system used is also presented.