Two-dose varicella vaccine effectiveness and rash severity in outbreaks of varicella among public school students

BACKGROUND

Universal 2-dose varicella vaccination was recommended in 2006 to further reduce varicella disease burden. This study examined 2-dose varicella vaccine effectiveness (VE) and rash severity in the setting of school-associated varicella outbreaks.

METHODS

A case control study was conducted from January 2010 to May 2011 in all West Virginia public schools. Clinically diagnosed cases from varicella outbreaks were matched with classmate controls. Vaccination information was collected from school, health department and healthcare provider immunization information systems.

RESULTS

Among the 133 cases and 365 controls enrolled, VE against all varicella was 83.2% [95% confidence interval (CI): 69.2%-90.8%] for 1-dose of varicella vaccine and 93.9% (95% CI: 86.9%-97.1%) for 2-dose; the incremental VE (2-dose vs. 1-dose) was 63.6% (95% CI: 32.6%-80.3%). In preventing moderate/severe varicella, 1-dose varicella vaccine was 88.2% (95% CI: 72.7%- 94.9%) effective, and 2-dose vaccination was 97.5% (95% CI: 91.6%-99.2%) effective, with the incremental VE of 78.6% (95% CI: 40.9%-92.3%). One-dose VE declined along with time since vaccination (VE = 93.0%, 88.0% and 81.8% in <5, 5-9 and ≥ 10 years after vaccination, P = 0.001 for trend). Both 1- and 2-dose breakthrough cases had milder rash than unvaccinated cases (<50 lesion: 24.6%, 49.1% and 70.0% in unvaccinated, 1-dose and 2-dose cases, P < 0.001), and no severe disease was found in 2-dose cases.

CONCLUSIONS

Two-dose varicella vaccination is highly effective and confers higher protection than a 1-dose regimen. High 2-dose varicella vaccination coverage should maximize the benefits of the varicella vaccination program and further reduce varicella disease burden in the United States.

Cephalometric analysis of families with dominantly inherited Crouzon syndrome: an aid to diagnosis in family studies

Crouzon syndrome (CS) is an autosomal dominant condition comprising orbital proptosis, midfacial hypoplasia, premature sutural synostosis, and altered proportions of bone lengths in the hands. In families the CS trait is highly variable. Several cases of affected sibs born to unaffected parents have been explained by germinal mosaicism. We hypothesized that cephalometric and metacarpophalangeal analysis may help to classify affected and unaffected subjects within families when clinical diagnosis is difficult. Posterior-anterior and lateral cephalometric radiographs and hand films were taken of 10 CS patients and 18 unaffected relatives. Sixty-two craniofacial and 19 hand linear and angular measurements were made on each subject and standardized by conversion to z-scores using published normal standards. Ten craniofacial variables were selected for use in a stepwise forward discriminant function analysis to develop an equation which could be used to discriminate CS patients from normal subjects. A two-group discriminant function using four craniofacial variables and one hand variable correctly classified the CS patients and relatives 100% of the time. The results suggest that relatively few facial variables are needed to differentiate most cases of CS but the addition of one or more hand variables may increase the sensitivity. DNA testing is necessary to adequately demonstrate incomplete penetrance in CS, but pretesting subjects for molecular studies using these methods may improve results.

Cephalometric evidence for a dominantly inherited predisposition to cleft lip-cleft palate in a single large kindred

Several studies have demonstrated an association between facial shape in parents and the presence of oral clefts in their offspring. However, these observations have been of little practical value because it has been assumed that facial shape was just one predisposing component among many in a multifactorial model of inheritance. Cephalometric analysis of a large family with 5 generations of affected individuals suggests that facial shape can be used to identify presumed carriers of a major gene associated with an increased risk for oral clefts. Discriminant function analysis indicates that such at risk individuals can be recognized effectively through a combination of increased midfacial and nasal cavity widths, reduced facial height, and a flat facial profile. The ability to identify minimally affected gene carriers within families would provide critical information needed in the search for molecular markers that segregate with the genetic risk for clefting.

Quantitation of craniofacial anomalies in utero: fetal alcohol and Crouzon syndromes and thanatophoric dysplasia

The study of fetal growth and development by ultrasound has been greatly facilitated in the past few years by the availability of anthropometric standards for the fetal body. Thus, the obstetrician is able to discern between normal and grossly abnormal, and even to quantitate certain fine fetal structures such as the face. This paper presents results obtained from a group of 5 patients referred to the Medical Center from private practices in Indianapolis, Indiana. Prenatal cephalometric analyses by ultrasound suggested the presence of craniofacial anomalies in all 5 cases. However, such defects were not detectable by routine ultrasonographic examination. A clinical examination after birth of each of these 5 patients suggested the following diagnoses: Fetal Alcohol Syndrome (FAS) in 2 individuals, Fetal Alcohol Effects (FAE) in one individual, Crouzon Syndrome (CS) in one patient, and Thanatophoric Dysplasia (TD) in one patient. In order to compare the craniofacial measurement values for each patient to normal standards, we developed Z-Score profiles and Pattern Variability Indexes (PVI) as described by Garn et al. [1984, 1985]. The values presented here support the idea that even mildly abnormal fetal craniofacial patterns are detectable by this relatively new application of ultrasound. At the present time, no conclusions can be made regarding the diagnostic accuracy of these patterns and profiles. However, the potential value of fetal cephalometry for documenting craniofacial dysmorphology is clearly indicated.

X-linked (recessive) hypomaturation amelogenesis imperfecta: a prosthodontic, genetic, and histopathologic report

A 16-year-old white girl requested esthetic restorations for her teeth. She was a manifesting heterozygote for the X-linked recessive form of amelogenesis imperfecta with hypomaturation defect. Lyonization theory states that in the somatic cells of female mammals, one of the two X chromosomes is randomly inactivated early in development. Therefore, females who are heterozygous for a given X-linked gene will be mosaic with varying proportions of cells in which only one of a particular pair of alleles is active. This mosaicism produced by lyonization ensures considerable phenotypic variability in the clinical expression of X-linked disorders. Histologic examination of the patient's extracted third molars demonstrated the expected lyonization effect. The patient received six porcelain laminate veneered crowns to restore her maxillary incisor and canine teeth. This article represents the first reported use of such restorations to alleviate the cosmetic and functional handicaps that accompany this genetic disease.

Clouston syndrome: a rare autosomal dominant trait with palmoplantar hyperkeratosis and alopecia

A caucasian family is reported in which four males and four females in two generations have exhibited alopecia, dysplastic nails, and hyperkeratosis of palmar and plantar surfaces. This type of ectodermal dysplasia, Clouston syndrome, features normal teeth with severe hair and nail dysplasia.

Bone dysplasias: the prenatal diagnostic challenge

The prenatal diagnosis of bone dysplasias presents difficult challenges for the clinician involved in monitoring pregnancies. Such diagnoses highlight delicate ethical issues and may require difficult decision-making when the differential diagnosis includes a lethal bone dysplasia. Despite the rapid technological advances in ultrasonography, the ability to make prenatal diagnoses within this group of disorders is limited by the restricted ultrasonographic capability to appreciate fully the detailed fetal anatomy. However, we perceive that a significant further limitation involves the lack of a systematic protocol to guide the clinician in the ultrasonographic evaluation of a fetus suspected of having a skeletal dysplasia. In an attempt to aid the clinician who is evaluating these suspected pregnancies, we report here 8 cases and propose a model protocol for the ultrasonographic diagnostic approach to fetal skeletal problems in utero.

Improved outcome in Pierre Robin sequence: effect of multidisciplinary evaluation and management

Infants with complications of Pierre Robin sequence are at increased risk of airway obstruction and resultant hypoxia, cor pulmonale, failure to thrive, and cerebral impairment. In an effort to minimize such complications, patients with Pierre Robin sequence were examined prospectively by a multidisciplinary team using polysomnography and continuous oximetry. Obstructive apnea and desaturation occurred in 18 of the 21 patients studied. Four children required only home apnea monitoring, and six required only monitoring and supplemental oxygen. Seven children had lip-tongue adhesion procedures performed, and four required tracheostomy. No patients died. All patients with isolated Pierre Robin sequence had normal development at follow-up except for one child who had experienced a respiratory arrest before referral. With improvements in neonatal intensive care, testing for respiratory assessment, improved surgical and postoperative intervention and home monitoring, the morbidity and mortality for children with Pierre Robin sequence can be reduced markedly.

Facial morphometrics in the identification of gene carriers of X-linked hypohidrotic ectodermal dysplasia

Roentgenographic measurements and morphometric analysis were employed in the investigation of contrasting patterns of craniofacial variation between normal individuals and those affected by X-linked hypohidrotic ectodermal dysplasia (HED). The research objective was to identify and describe the facial characteristics of heterozygous gene carriers who show minor expression of the disorder. In this study of 13 HED families with 16 affected males, 12 carriers, and 12 normal individuals, affected individuals had at least 3 of the following 4 clinical signs and symptoms: a) hypodontia, b) hypohidrosis, c) hypotrichosis, and d) clinically distinct facial physiognomy. By contrast, the gene carriers manifested only one or 2 or none of the 4 clinical manifestations. In a preliminary comparison of gene carriers vs. normal individuals, we have generated 2 discriminant functions (each based on 3 facial measurements taken either from the lateral or frontal cephalograms). These 2 functions correctly diagnose 100% of the gene carriers and normal HED relatives. Facial anomalies characteristic of the gene carriers were 1) abnormally narrow and short maxillary width and palatal depth dimensions; 2) very small and retrusive malar and maxillary regions; 3) markedly reduced lower facial depth, height and width dimensions; 4) small head height, prominent forehead, and high-set orbits; 5) a generalized, symmetric reduction of the whole craniofacial complex.

A study of cephalometric features in cleft lip-cleft palate families. I: Phenotypic heterogeneity and genetic predisposition in parents of sporadic cases

Several previous studies have indicated that unaffected parents of children with nonsyndromic cleft lip and palate show unusual craniofacial features. This study reexamines this question by applying multivariate cluster analysis to lateral cephalometric head plates from 82 individuals who are parents of sporadic cases of cleft lip with or without cleft palate (CL/P). Considerable phenotypic heterogeneity was present within the sample. Three major groupings were defined. Two of these groups showed cephalometric similarities to individuals with overt clefts, while the third showed a generalized concordance to published norms. In almost every case only one member of each parental pair showed the cleft related cephalometric phenotype, suggesting the possibility of a substantial genetic component in many cases of sporadic CL/P. However, there were several cases in which neither parent showed the phenotypic traits. Such cases may have a different etiology or a greater environmental component.

Fetal craniofacial morphometrics: in utero evaluation at 16 weeks' gestation

Although ultrasound has proved useful in the diagnosis of fetal craniofacial malformations, its success has been based primarily on subjective clinical observations of apparent abnormal fetal structures, their proportions, and unusual features. However, such clinical observations may be misleading and ideally should be validated by standardized quantitative measurements. We describe here an ultrasonographic methodology that has provided quantitative data describing the normal fetal craniofacies at 16 weeks of gestation. This report is part of an ongoing research project directed at describing fetal facial morphology in utero at different gestational ages. Such data can be used to construct growth curves to which observations from suspected abnormal fetuses can be compared. A total of 53 patients were evaluated at 16 weeks of gestation, at which time 24 craniofacial linear and angular measurements were made. The landmarks employed for these measurements were those used in roentgencephalometry so that this fetal data base could be related to postnatal populations. Such data will contribute not only to a description of facial dysmorphogenesis but also to a better understanding of normal facial growth and development. Furthermore, they constitute a useful tool for prenatal diagnosis, gestational aging, growth predictions, and perhaps for as yet relatively unexplored fields such as fetal therapy.

Antley-Bixler syndrome from a prognostic perspective: report of a case and review of the literature

The Antley-Bixler syndrome (ABS) is characterized by craniosynostosis, radiohumeral synostosis, and femoral bowing. Other findings include a trapezoid-shaped head, deformed ears, severe midface hypoplasia, choanal atresia or stenosis, and long bone fractures. Most ABS cases have died in the first months of life from respiratory complications. The poor prognosis in this condition makes counseling difficult and early termination of pregnancy a consideration. The medical and surgical management information presented here can be used as a guide for counseling parents in the future. We report on a new patient with ABS who now at age 3 yr, has been followed by the medical staff of Riley Children's Hospital since birth. She has had successful medical and surgical management. Although the multisynostoses seen in this disorder is undoubtedly related to the soft tissue malformations such as choanal stenosis and midface hypoplasia, the cause remains unknown. The literature is also reviewed in this condition.

Anthropometric analysis of the face in hypohidrotic ectodermal dysplasia: a family study

Sixteen individuals with hypohidrotic ectodermal dysplasia (HED) were compared to normal standards as well as to 16 unaffected family members by using a series of 20 anthropometric measurements of the head and face. Individuals with HED were generally smaller than normal controls or their unaffected relatives. However, this size reduction was not uniform. Instead, it was most evident in the anterior-posterior dimensions of the lower two-thirds of the face, in facial height, and in the size of the ears, nose, and mouth. A stepwise discriminant function analysis indicated that a function constructed from four variables (depth of the lower face, width of the nose, mandibular arc, and total facial height) could accurately classify 96.7% of the 32 individuals in the combined sample of affected and unaffected individuals. These findings demonstrated that the face of individuals with HED is unique and can be useful in its diagnosis. Additional studies are needed to determine if similar-though-less-pronounced facial abnormalities can be used to detect minimally affected gene carriers of this presumably X-linked condition.

Urorectal septum malformation sequence. Report of six cases and embryological analysis

We encountered six female infants with a specific pattern of developmental abnormalities of the urogenital and lower intestinal tracts. The anomalies included ambiguous genitalia, lack of perineal openings, and müllerian and urinary tract anomalies. Each patient had normal female chromosomes and normal adrenal gland function. We believe that this combination of anomalies represents a recognizable and specific sequence that is due to a failure of migration to and/or fusion of the urorectal septum with the cloacal membrane. This, in turn, we postulate, leads to persistence of the cloaca and cloacal membrane and failure of normal differentiation of the external genitalia. Persistence of the cloacal membrane results in absence of the urethral and vaginal openings and an imperforate anus. We propose calling this entity the urorectal septum malformation sequence.

Suggestion of linkage of a major locus for nonsyndromic orofacial cleft with F13A and tentative assignment to chromosome 6

A Danish material of 58 pedigrees with nonsyndromic orofacial cleft, selected out of a comprehensive Danish material for suggestiveness of autosomal dominant inheritance, was studied for linkage with 42 non-DNA polymorphic marker systems. Both cleft lip with or without cleft palate (CL(P)) and cleft lip alone (CP) were, for the purpose of linkage analysis, scored as if they were due to an autosomal dominant gene with complete penetrance. The highest lod score was with the blood clotting factor XIIIA (F13A): for males alone z = 3.40 at theta = 0.00, for females alone z = 0.30 at theta = 0.21, and for these together z = 3.66 at at theta = 0.00 for males and 0.26 for females. Since F13A is known to be located distally on chromosome 6, we tentatively assign a major locus for orofacial cleft to this region. Since both CL(P) and CP pedigrees contribute to the positive score, the question arises whether this locus carries two cleft alleles.

Segregation analysis of cleft lip with or without cleft palate: a comparison of Danish and Japanese data

The genetic basis of cleft lip with or without cleft palate [CL(P)] remains unresolved. The controversy on the role of a major gene is confounded with possible population differences. This study examines the issue of population differences by comparing two contrasting populations: Caucasians and Japanese. Japanese are known to have higher population incidence of CL(P) and yet lower recurrence risks among relatives. The study subjects consist of 2,998 nuclear families of the Danish population and 627 families of the Japanese population. The uniformly coded data were subjected to complex segregation analysis based on the mixed model. The analysis has revealed that the Danish data can be best explained by a combination of major gene action and multifactorial inheritance. The best-fitting model is characterized by recessive gene with displacement effect (t) of 2.7 in the standardized unit and gene frequency of .035. The heritability is estimated as .97. The transmission probability of Aa----a for the major gene is consistent with 1/2. On the contrary, the Japanese data can be best accounted for only by multifactorial inheritance with the heritability estimate of .77. No major heterogeneity could be detected between subsets of the data within the populations as grouped by types of ascertainment or mating. It is thus concluded that the observed inconsistency between the two populations is explained by a significant role of major gene in the Caucasian population, but not in the Japanese population.

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.