Parent to child transmission of the thrombocytopenia absent radius (TAR) syndrome

We report on cases of the thrombocytopenia absent radius syndrome (TAR) in a family with the first documented occurrence of parent-to-child transmission. At least three other families have been reported in which TAR has been transmitted across generations. The pattern of transmission in these cases is not consistent with the simple autosomal recessive mode of inheritance which has been proposed. TAR syndrome may be a genetically heterogeneous disorder of the result of one of a group of related alleles. Given the increasing evidence for genetic and causal heterogeneity in TAR together with its similarity to conditions such as Holt-Oram, WT Limb-Blood and SC-Roberts Phocomelia syndromes it may be reasonable to view TAR as a developmental field defect rather than a genetic syndrome. Genetic counseling of affected individuals and their families should be modified to reflect the possibility of a recurrence risk as high as 50%.

Human parotid proline-rich proteins: correlation of genetic polymorphisms to dental caries

Parotid saliva contains a variety of proline-rich proteins. This study found that, among 306 children between the ages of 5 to 15 years, there is a significant increase in the decayed-missing-filled tooth surface (DMFS) score of the permanent teeth with age in children with the specific proline-rich protein phenotypes Pa and Pr. However, the increase in DMFS score of the permanent teeth of children was significantly greater in children with Pa+ and Pr22 than in those with the other phenotypes (Pa- or Pr11 and Pr12). The previously established close correlation between the Pa and Pr phenotypes and the genetic variants of salivary peroxidase (a powerful antibacterial system in the oral cavity) may provide an explanation for the relationship of certain proline-rich protein phenotypes to dental caries.

Gingival fibromatosis with sensorineural hearing loss: an autosomal dominant trait

Gingival fibromatosis is a heterogeneous entity that can occur both as a part of syndromes and as an isolated trait. We describe the second family with a rare, dominantly inherited syndrome of gingival fibromatosis and progressive sensorineural hearing loss.

Interradicular dentin dysplasia associated with amelogenesis imperfecta

Very few reports are available on the occurrence of dysplasia of both enamel and dentin. This report concerns a rare association of amelogenesis imperfecta with a dysplasia of dentin in the interradicular area in sisters of Japanese descent who have no other morphologic anomalies. Retarded tooth eruption was also a clinical feature in both sisters. Histologic examination of several teeth revealed that the anomalous interradicular dentin consisted of a mass of small, onion-like calcified bodies. The absence of any dental abnormalities in both parents, who are related as first cousins, supports the concept of autosomal recessive inheritance for this trait.

Gustatory lacrimation in association with the branchio-oto-renal syndrome

Branchio-oto-renal (BOR) syndrome is a developmental complex presenting with various combinations of ear pits, branchial cleft cysts, deafness and renal anomalies, which is inherited as an autosomal dominant trait. This report describes a father and 2 children with BOR syndrome in which gustatory lacrimation (GL) was also present in 2 of them. GL is considered to be a rare, non-hereditary type of anomalous, cranial nerve-end organ innervation. Since lacrimal stenosis, which can clinically mimic GL, is also a feature of the BOR syndrome, future reports require lacrimal reflex testing and duct patency evaluation to define this variation in the BOR phenotype.

Fetal mortality in oral cleft families (IX): factors relating to the occurrence of sporadic clefts

Pedigree data on 854 probands with cleft lip and/or cleft palate from the State of Indiana are presented. These include 123 probands with cleft lip alone (CL), 453 with cleft lip and palate (CLP), and 278 with isolated cleft palate (CP). Probands and families were interviewed at the Indiana University Medical Center during the years 1962-1980. Among features of special interest are an excess of bilateral CLP (46% of all CLP cases) and a significantly greater number of older mothers and fathers (over 34 years old) than in the general population. An apparent increase in the proportion of sporadic cases with time may be due to bias in ascertainment. It is suggested that the increased proportions of more severe clefts and older parents are among several factors which contribute to the incidence of fetal mortality in a cleft population. The association of fetal mortality with liability to clefting introduces a more precise way to define a sporadic cleft. That is, a truly sporadic cleft is one conceived as a single occurrence event and has survived to become a liveborn cleft child whereas other apparently sporadic cleft individuals represent the surviving cleft in a sibship in which fetal mortality has eliminated all other cleft offspring already conceived. This observation has applications to the collection and interpretation of genetic pedigree data for clefts as well as many other genetic conditions.

The Nance-Horan syndrome: a rare X-linked ocular-dental trait with expression in heterozygous females

This report describes two families with the Nance-Horan syndrome, an X-linked trait featuring lenticular cataracts and anomalies of tooth shape and number. Previous reports have described blindness in affected males but posterior sutural cataracts with normal vision as the primary ocular expression in heterozygous females. In one of these two families, the affected female is not only blind in one eye but reportedly had supernumerary central incisors (mesiodens) removed. This constitutes the most severe ocular and dental expression of this gene in heterozygous females yet reported.

Bilateral macrostomia in one of monozygotic twins

This report concerns a pair of monozygotic twins discordant for bilateral symmetrical macrostomia. Laterally placed, symmetrical notches in the vermilion borders of both upper and lower lips were apparent in the affected twin. Since the oral cavity walls develop by a differential growth and merging mechanism, this result suggests a mechanism of tissue breakdown as the cause of macrostomia. Furthermore, discordance in these monozygotic twins minimizes the importance of heredity in this malformation.

Fetal mortality in oral cleft families (V): Studies of sporadic vs familial and pure vs syndromic clefts

The frequencies of fetal deaths in sibships of oral cleft probands are analysed in relation to sporadic or familial clefts, and pure or syndromic clefts. In a study of 1823 pregnancies in 630 sibships of probands with CL(P), the frequency of fetal deaths was found to be increased, but not significantly, in the sporadic group as compared to the familial group of sibships from Indiana. However, such an increase was found to be significant in the Montreal data. The pooled data from both these centers also show a significant increase in the sporadic group. For CP, no such differences were found. Similar comparisons of fetal mortality in relation to pure and syndromic clefts indicated that the frequencies of fetal deaths were consistently elevated in sibships of probands with syndromic clefts with one exception, which is the Indiana CP group where the lowest frequency of fetal deaths was observed in the sibships. This group mostly consisted of sibships with solitary pregnancies. This may have been a result of early zygotic mortality in this group. Further data will be obtained to confirm this observation.

Fetal mortality in oral cleft families (VII): Birth intervals

Birth intervals in sibships of oral cleft probands are analysed to detect prolonged delays between successive pregnancies. Such intervals are useful indicators of undetected fetal mortality. The present study indicates that the average interval for 462 cleft families in Indiana is 30.61 months. The average interval leading to the birth of a cleft child is 33.94 and is significantly greater than the average interval for the entire sample. Although the contraception status of the Indiana population is not known, the significantly greater delay preceding the birth of a cleft child is indicative of a cause other than contraception. This finding is in agreement with the report by Drillien et al. (1966) that abnormal conceptions occur more frequently adjacent to cleft offspring. It is interesting that some increase in the average interval is also noted in the present study immediately following the birth of a cleft child. Such delays occurring both preceding and following the birth of a cleft child (in contrast to smaller intervals for other pregnancies in the same sibships) may indicate excessive fetal wastage due to a combination of genetic and environmental factors.

Fetal mortality in oral cleft families (VI): a search for early embryonic and zygotic mortality

A hypothesis concerning the detection of early embryonic and zygotic mortality in oral cleft families is presented. It is suggested that probands from solitary pregnancies are the result of a higher liability to clefting which eliminated potential siblings prior to the conception of the proband. A positive association between the degree of liability to clefting and fetal mortality has already been established by the authors' previous work. In sibships of solitary probands, such liability is assumed to have caused early embryonic and zygotic mortality which eliminated potential siblings and recognizable fetal loss. This hypothesis can be tested by an examination of the sex-ratios in probands from solitary pregnancies and those from multiple pregnancies. For CL(P), a decrease in the proportion of males would be expected in probands from solitary pregnancies in comparison to those from multiple pregnancies. For CP, however, an increase in the proportion of males in solitary probands is expected in comparison to those from multiple pregnancies. This hypothesis is applied to 613 CL(P) probands and 317 CP probands from Indiana. Although the expected decrease (for CL(P)) and increase (for CP) in the proportion of males in solitary probands is not quite significant, the trends are in the expected directions. It is suggested that the hypothesis should be tested further with additional data on oral clefts and other similar anomalies.

Probable autosomal recessive inheritance of polysplenia, situs inversus and cardiac defects in an Amish family

We report on an Amish family with five individuals in two generations with complex congenital heart disease. Autopsy findings in one and clinical examination in the others support the diagnosis of polysplenia "syndrome." In a mouse model, this spectrum of situs abnormalities and cardiovascular defects shows recessive inheritance with homozygotes having either situs solitus or situs inversus or ambiguous situs. The parents of the four affected sibs are fourth cousins. We think that the father of these four children is an affected but clinically normal homozygote, that his deceased sister was an affected homozygote, and it seems likely that they too had consanguinous parents.

Clouston syndrome: an ultrastructural study

A previously undescribed French-Canadian family affected with Clouston Syndrome (Hypohidrotic Ectodermal Dysplasia) is described. Ultrastructural study of the hair shows disorganization of the hair fibrils with loss of the cuticular cortex. The SEM findings are consistent with the model, suggesting a biochemical defect in the keratin of the integumentary system.

Fetal mortality in oral cleft families(IV): the "doubling effect"

Fetal mortality data from Lancaster, Penn., Chicago, Ill. and Minneapolis, Minn. are presented which support the authors' earlier findings in Indiana and Montreal that a positive relationship exists between the degree of liability to malformation and the incidence of fetal deaths in probands' sibships. Altogether, the study involved 189 CL sibships, 690 CLP sibships, and 3,416 pregnancies. On the basis of these data, which are derived from families of several different backgrounds of European ancestry, it is generalized that, as we proceed from CL sibships to CLP sibships, there is a doubling effect on fetal mortality. The consistency of this finding in several population samples is impressive. The implications of this observation are discussed with reference to genetic counseling.

Fetal mortality in oral cleft families: data from Indiana and Montreal

Analysis of 418 sibships of oral cleft probands from Indiana, and 288 sibships from Montreal indicate that the incidence of fetal mortality is significantly greater in sibships of probands with cleft lip and cleft palate (CLP) as compared to that in sibships of probands with cleft lip (CL) alone. These findings support a multifactorial-two-threshold concept, according to which a lower level of liability results in clefting whereas a higher level of liability causes fetal deaths. They add confirmatory evidence in support of the authors' earlier work, utilizing data from two different sources.

Fetal mortality and cleft lip with or without cleft palate

Analysis of fetal mortality in sibships of 406 probands with cleft lip with or without cleft palate (CL(P)) indicates that the incidence of fetal mortality is significantly greater in sibships of probands with bilateral CL(P) than in those of unilateral CL(P). The difference is even greater when fetal mortality in sibships of male probands with unilateral CL(P) is compared with that of female probands with bilateral CL(P). These findings support a multifactorial two-threshold concept in which a lower level of liability results in clefting while a higher level of liability causes fetal mortality.

Fetal mortality associated with cleft lip and cleft palate

Analysis of 1,516 pregnancies in sibships of probands with cleft lip with or without cleft palate [CL(P)], and 774 pregnancies in those of probands with isolated cleft palate (CP) indicated that fetal mortality significantly increases with liability to clefting. These data are compatible with the multifactorial two-threshold model, according to which a lower threshold level of liability results in a cleft formation whereas a higher level of liability causes a fetal death.

A clinical, genetic, and ultrastructural study of snow-capped teeth: amelogenesis imperfecta, hypomaturation type

Snow-capped teeth (SCT) is a rare form of amelogenesis imperfecta, hypomaturation type. It has been alluded to on numerous occasions but, to our knowledge, no pedigree or clinical-histopathologic data have been published. In this report, two families are described. Scanning electron microscopic (SEM) studies of unetched teeth from affected persons revealed numerous defects of the enamel surface. After etching with 10 percent hydrochloric acid for 21/2 minutes to remove the outer prismless layer of enamel, SEM features of the enamel prism were essentially identical to those of normal teeth. These findings suggest that the structural defect in SCT is confined to the outer prismless enamel layer and that the bulk of the enamel is normal. The genetic analysis supports the concept that SCT is inherited in an X-linked recessive fashion and not as an autosomal dominant trait, as previously reported.

Cleft palate: a genetic and epidemiologic investigation

An examination of kindred histories of 561 Danish probands who have non-syndromic CP has indicated that neither a multifactorial-threshold model nor a single major locus model is completely compatible with the data. This suggests etiologic heterogeneity for CP, which was tested with kindred data. As recommended by Smith (1976), at attempt to define partially this heterogeneity within the CP phenotype was undertaken by grouping and comparing the kindred data. It is both reasonable and heuristic to propose that CP,, as defined in this investigation, is composed of three groups: (1) Syndromic CP; (2) Familial CP, which appears to have an autosomal dominant component to its etiology, and (3) Non-familial CP which, by demonstrating an increasing frequency of CP and a maternal age effect, appears to be related to environmental factors which may cause CP or other malformations.