A cephalometric study of fetal alcohol syndrome

Dentofacial characteristics of children and adolescents with foetal alcohol spectrum disorders: a comparison with matched controls

BACKGROUND

Foetal alcohol spectrum disorders (FASD) include somatic and neurological developmental disturbances after prenatal alcohol exposure, including facial anomalies. However, the knowledge of the orthodontic skeletal and dental cephalometric relations in this group is limited. The aim of the study was to assess the dentofacial characteristics of children and adolescents with FASD and to compare them with a matched control group.

METHODS

The study group comprised all available children and adolescents diagnosed with FASD (> 7 years of age) in whom good quality cephalograms were available. The control group comprised non-syndromic, orthodontically untreated children with normal occlusion and skeletal relations matched with age and gender. Cephalometric analysis included eighteen linear and angular measurements. The general linear model for repeated measures regarding age, gender and the type of FASD was applied.

RESULTS

The group with FASD included 35 individuals (21 girls and 14 boys) aged 7-18 years including 21 with foetal alcohol syndrome. The mean age in the study and the control group was 12.8 years (SD, range 3.2, 7.1-18.1) and 13.0 (SD, range 2.9, 9.1-18.1), respectively. Statistically significant differences between the groups were found in 15 out of 18 of the cephalometric measurements (83%). In children with FASD the mandible was more retrusive, the incisors were more proclined and the mandibular incisors and the lips were more protruded when compared with controls. There was no significant evidence of an influence of age, gender or FASD type.

CONCLUSIONS

Dentofacial characteristics of children and adolescents with FASD significantly differ from controls. Early orthodontic diagnosis and prophylaxis should play a part of the interdisciplinary care of patients in this group.

Craniofacial skeletal deviations following in utero exposure to the anticonvulsant phenytoin: monotherapy and polytherapy

OBJECTIVE

To identify and quantify the craniofacial effects from prenatal exposure to phenytoin monotherapy and polytherapy using cephalometric, hand-wrist, and panoramic radiographs and to determine if such deviations persist with age.

DESIGN

Craniofacial structures of 28 anticonvulsant-exposed individuals were evaluated using 20 landmarks in lateral cephalometric radiographs and 19 landmarks in frontal cephalometric radiographs. Skeletal maturity was assessed using hand-wrist radiographs. Dental maturity and the presence of dental anomalies were evaluated using panoramic radiographs. Eleven individuals were re-evaluated 7 years later, on average, to determine the persistence of any measured deviations.

SETTING AND SAMPLE POPULATION

Department of Growth and Development, Harvard School of Dental Medicine and Massachusetts General Hospital. Patients were recruited from several sources.

OUTCOME MEASURE

The evaluated dimensions included linear, angular, and proportional measures.

RESULTS

The most common deviations were decreased height and length of the maxilla, decreased length of the posterior cranial base, length of the mandible, cranial width and level of the cribriform plate, and a decrease in the Wits Appraisal assessment. The deviations were more significant in the polytherapy-exposed individuals than in the monotherapyexposed individuals. These deviations, especially in the maxilla, persisted with age as revealed in a re-evaluation of 11 individuals.

CONCLUSION

The craniofacial skeletal findings among individuals exposed in utero to phenytoin monotherapy or phenytoin polytherapy, when considered in aggregate, suggest a mild pattern of maxillary hypoplasia that becomes more pronounced with age.

New perspectives on the face in fetal alcohol syndrome: what anthropometry tells us

Fetal alcohol syndrome (FAS) refers to the adverse effects to the fetus from prenatal exposure to alcohol. Originally, the diagnosis of FAS was given only to those individuals that were the most severely affected. Since that time, it has become apparent that the effects of prenatal alcohol exposure are broad-based, and those individuals diagnosed with FAS represent the severe end of the continuum in their phenotypic expression. This study utilized 21 craniofacial anthropometric measurements on 100 prenatally exposed individuals to quantify the elements of the FAS facial phenotype and to extend the quantitative phenotype to individuals who exhibited less severe or incomplete manifestations of prenatal alcohol exposure.

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.

Dysmorphic features in offspring of alcoholic mothers

The frequencies of 60 minor physical anomalies and various craniofacial measurements in 52 children with alcohol exposure of various durations in utero were determined and compared with 48 non-exposed healthy children at a mean age of 27 months. Compared with non-exposed children a significantly higher total minor physical anomaly count was observed in those children exposed prenatally to alcohol throughout pregnancy. Binge drinking was not associated with an increased minor physical anomaly count. During the first year of life facial features were judged according to subjective impression: 10 children had typical facial features of fetal alcohol syndrome (FAS) and 19 children were judged to have possible fetal alcohol effects on their face. Only six of them fulfilled the strict craniofacial criteria for diagnosis of FAS at the age of 27 months. Our results stress the importance of recognising also the subtle dysmorphic facial features associated with prenatal alcohol exposure: 22 of 29 (76%) of exposed children judged to have typical or possible features of FAS during the first year showed signs of central nervous system dysfunction at the age of 27 months.

Holoprosencephaly in a fetal macaque (Macaca nemestrina) following weekly exposure to ethanol

Previous studies in rodents have indicated that the facial changes of fetal alcohol syndrome (FAS) closely resemble those of a mild form of holoprosencephaly. In order to examine this relationship in non-human primates, we evaluated a 133-day gestation macaque (Macaca nemestrina) with holoprosencephaly, median cleft lip and palate, and encephalocele. The mother had been given ethanol once per week (1.8 g/kg body weight) from weeks 2 to 19 postconception. Diagnosis of holoprosencephaly was made following ultrasound evaluation for polyhydramnios and delivery of the female fetus by caesarean section. Another fetus of identical age was delivered by caesarean section for use as a control. Both fetuses were studied by anthropometric, gross, radiographic, and histologic techniques. In the fetus exposed to alcohol, no extracranial anomalies were identified and the karyotype was normal. The brain was micrencephalic, with absent olfactory bulbs, tracts, optic nerves and chiasma, fused frontal lobes, and a single, dilated lateral ventricle; a parietooccipital encephalocele consisted of thin, dysplastic cortex bordering the ventricle; the cerebellum was dysplastic and superiorly displaced. Within the craniofacial complex, anophthalmia was bilateral; premaxillary components were absent, palatal shelves separate, the maxillae closeset, and the ethmoid bone small and deformed. Most of these defects are similar to those encountered in humans with holoprosencephaly and support the hypothesis of shared etiologic and pathogenetic relations between the facial anomalies of fetal alcohol syndrome and holoprosencephaly.

A cephalometric assessment of children with fetal alcohol syndrome

Lateral cephalometric radiographs were quantitatively assessed in a series of 15 American black children with fetal alcohol syndrome (FAS). Although none was profoundly affected, FAS had been diagnosed in all the children at birth. Comparisons with age-, sex-, and race-matched controls disclosed a triad of facial profile differences: (1) frontal bossing, (2) palatal plane tipped up in the front with proclined upper incisors and a sharp nasolabial angle acquired from digit habits, and (3) above-average length of the mandibular corpus. Collectively these generate the perception of midface hypoplasia, although the midface actually is unremarkable in size and position. A high prevalence of chronic digit habits (8 of 15) is a secondary consideration in FAS, leading to localized skeletodental problems.

Clinical anthropometry and medical genetics: a compilation of body measurements in genetic and congenital disorders

Anthropometry has become an important tool in the study of genetic conditions, particularly as a diagnostic aid for the clinical geneticist. However, many practicing physicians do not do anthropometry of patients for several reasons, such as: appropriate measurements in a given situation are unknown; normative reference data are unavailable; or analysis and interpretation of the data are confusing. In this review we present an annotated compilation of informative measurements for hereditary and congenital disorders and a guide to normative anthropometric data of use in evaluation and diagnosis of such disorders. Further development of multivariate approaches will enhance the application of anthropometry as a means of identifying and classifying a syndrome and documenting the natural history of many disorders. Continued cooperation among physicians, geneticists, and anthropologists for the collection and assessment of patient and normative data is essential if these goals are to be realized.

Roentgenographic cranial-base and calvarial measurements of Jamaican children between one month and five years

Three-hundred-and-thirty lateral skull-films obtained from apparently healthy normocephalic Jamaican children between the age of one month and five years were studied, using bony reference points nasion (N), tuberculum sellae (Ts), internal occipital prominence (IOP), inion (I), bregma (B) and lambda (L). Cranial-base length was measured between N-Ts, Ts-IOP and N-I. Calvarial height was measured between Ts-B (anterior calvarium) and Ts-L (posterior calvarium). All the measurements showed an increase with age and were higher in boys. Significant correlations were seen between N-Ts and Ts-IOP, N-Ts and N-I, N-Ts and Ts-B, N-Ts and Ts-L and N-I and Ts-L at all the ages and in both sexes. Ratios between lengths of anterior and posterior cranial-base, as well as between cranial-base lengths and anterior cranial heights, were nearly constant at all the ages and in both sexes. These observations support the view that there is definite proportionality between the growth of anterior and posterior cranial-base lengths, and between anterior calvarial height and cranial-base lengths. On the other hand, a significant increase with age was seen in the ratios N-Ts/Ts-L, N-I/Ts/L and Ts/B/Ts-L, suggesting a progressive decrease in growth of posterior calvarial height. A comparison of the data with previously published figures for Indian and Norwegian populations suggests a racial difference in the various cranial-base and calvarial ratios.