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R J Jorgenson

Publications and source records attributed to R J Jorgenson.

At least 37 records · Page 2Linked to original sources
PubMed1984

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.

Aneuploidy↗
PubMed1984

Neurofibromatosis: oral and radiographic manifestations.

Oral manifestations of neurofibromatosis have been reported in only 4% to 7% of affected persons. All oral tissues, hard and soft, have been reported to be affected with tumors, but the tongue has been the most common site. We report on the oral and radiographic findings in twenty-two patients with neurofibromatosis. The prevalence of oral and radiographic findings in our sample was 72%, which is much higher than previously reported. The five most common findings are oral neurofibromas, enlarged fungiform papillae, intrabony lesions, wide inferior alveolar canals, and enlarged mandibular foramina.

Adolescent↗
PubMed1984

Studies on facial growth and arch size in cleft lip and palate.

A study of facial growth and palatal dimensions was done on 32 patients with unilateral cleft lip and palate. The study population, treated by a single surgeon, was separated into two groups: those whose palates were closed before age 4 years, and those whose palates were closed after 4 years. Maxillary growth was better in patients who had late surgery than in those who had early surgery. In addition, palatal dimensions were more nearly normal in the late group than in the early group.

Age Factors↗
PubMed1983

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.

Abnormalities, Multiple↗
PubMed1983

Clinical heterogeneity in the tricho-dento-osseous syndrome.

The tricho-dento-osseous syndrome (TDO syndrome) involves morphologic abnormalities of hair, teeth, and skeleton. Clinical findings of the TDO syndrome are excessively curly (fuzzy) hair, enamel hypoplasia, and skeletal findings of a generalized pattern of osseous sclerosis. We report an autosomal dominant syndrome with similar hair and teeth morphology, but with a skeletal dysplasia consisting of sclerosis and thickening of the calvarium with long bones that show subtle undertubulation but no sclerosis.

Adult↗
PubMed1983

Heterogeneity in genetic disorders that affect the orofacies.

The diagnosis of genetic disorders is complicated by multiple genetic causes for the same or similar disorders, phenotypic similarities of different disorders, and environmental disorders that resemble genetic ones. The clinical geneticist is well versed in identifying genetic heterogeneity, and the extent of the clinical heterogeneity and phenocopies for diseases with which he or she deals regularly. Nonetheless, the expertise of clinical geneticists form other specialties of medicine or dentistry may be useful in documenting heterogeneity that otherwise may be overlooked. The examples presented here illustrate that heterogeneity is as important to the dentist who practices clinical genetics as it is to the physician-clinical geneticist, and that a consultation with a properly trained dentist may be a useful part of a protocol for the genetic evaluation.

Anodontia↗
PubMed1983

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.

Dentition↗
PubMed1982

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.

Abnormalities, Multiple↗
PubMed1982

The prevalence of taurodontism in a select population.

The frequency of taurodontism was studied in 1074 black children from an inner city population. Based on the index that was developed, 4.37% of the sample were determined to be affected. The frequency of taurodontism was compared to other studies. Furthermore, tooth specific frequencies were calculated and the model for determining taurodontism was evaluated.

Adolescent↗
PubMed1981

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.

Adult↗
PubMed1980

XY gonadal dysgenesis in three siblings.

Three tall, phenotypic female siblings with XY gonadal dysgenesis were found to have short fourth metacarpal bones (bilateral in two and unilateral in the other). Clitoromegaly was observed in the two older siblings, without hirsutism. Bilateral streak gonads were found in all three. A gonadoblastoma was present in the left streak gonad of the youngest, and an adenomatoid tumor in the left streak gonad of the oldest, who was diabetic. Determination of androgens from peripheral and gonadal venous plasma revealed androgen secretion by the streak gonads. On the basis of clinical findings, familial tendency, and androgen secretion from the streak gonads in these patients, it is proposed that the XY gonadal dysgenesis represents a severe form of male pseudohermaphroditism.

Adenoma↗