The midline craniofacial skeleton in holoprosencephalic fetuses.

Craniofacial skeletal development in eight human holoprosencephalic fetuses from second trimester abortions were examined by radiography and histology. The whole spectrum of associated facial malformations from anophthalmia through cyclopia, ethmocephaly, cebocephaly, and median cleft lip to short philtrum was represented. Cases with the most severe facial malformations also had the most severely affected facial skeleton. In the facial skeleton, the premaxilla was most often affected; it was absent in seven cases and malformed in the one with only a short philtrum. This and other facial skeletal malformations can be explained as abnormal fusion of the facial bones because of defective development of the nasal cartilage. The occipital bones were normal, but the basicranial skeleton anterior to the spheno-occipital junction was affected in all cases. The findings support the hypothesis that the facial malformations in holoprosencephaly result from disturbance in embryonal life of the mesoderm at the rostral end of the notochord.     

Misclassification risk of patients with bilateral cleft lip and palate and manifestations of median facial dysplasia: A new variant of del(22q11.2) syndrome?

The generic term median facial dysplasia (MFD) describes a subgroup of patients with cleft lip and palate exhibiting characteristic craniofacial defects: (1) short prolabium, (2) absence of frenulum labii, (3) hypoplasia of premaxilla, (4) absent upper central and lateral incisors of the cleft side, and (5) deficient septal cartilage and nasal spine. Gross brain malformations are usually absent in MFD. The same craniofacial malformations are also described in patients with holoprosencephaly sequence (HPE-S). We report on two male patients with bilateral cleft lip and palate showing the facial findings of MFD or HPE-S. Additional congenital malformations were anal atresia in one patient and severe cardiac defect in the other. In both, HPE was excluded by brain imaging, although uncommon brain anomalies were detected consisting of multiple white-matter lesions in the one patient and unusual enlargement and tortuosity of intracerebral blood vessels in both patients. In addition to facial anomalies, the patients also had psychiatric problems typically seen in velo-cardio-facial syndrome (VCFS). Fluorescence in situ hybridization (FISH) analysis confirmed a 22q11.2 microdeletion in both.     

Misclassification risk of patients with bilateral cleft lip and palate and manifestations of median facial dysplasia: A new variant of del(22q11.2) syndrome?

The generic term median facial dysplasia (MFD) describes a subgroup of patients with cleft lip and palate exhibiting characteristic craniofacial defects: (1) short prolabium, (2) absence of frenulum labii, (3) hypoplasia of premaxilla, (4) absent upper central and lateral incisors of the cleft side, and (5) deficient septal cartilage and nasal spine. Gross brain malformations are usually absent in MFD. The same craniofacial malformations are also described in patients with holoprosencephaly sequence (HPE‐S). We report on two male patients with bilateral cleft lip and palate showing the facial findings of MFD or HPE‐S. Additional congenital malformations were anal atresia in one patient and severe cardiac defect in the other. In both, HPE was excluded by brain imaging, although uncommon brain anomalies were detected consisting of multiple white‐matter lesions in the one patient and unusual enlargement and tortuosity of intracerebral blood vessels in both patients. In addition to facial anomalies, the patients also had psychiatric problems typically seen in velo‐cardio‐facial syndrome (VCFS). Fluorescence in situ hybridization (FISH) analysis confirmed a 22q11.2 microdeletion in both. © 2001 Wiley‐Liss, Inc.     

PTCH mutations in four Brazilian patients with holoprosencephaly and in one with holoprosencephaly-like features and normal MRI

We report five Brazilian probands with PATCHED (PTCH) mutations and highly variable phenotypes with holoprosencephaly in four cases and holoprosencephaly-like facial features with a normal MRI in a fifth case. Three of our mutations were novel: Ala443Gly, Val751Gly, and Val908Gly. Two patients had the same mutation (Val908Gly), but were phenotypically different: alobar holoprosencephaly, absent nasal septum, and midline cleft lip-palate in one case, and lobar holoprosencephaly, macrocephaly, hypertelorism, clefting of the nose, severe microphthalmia, and a single maxillary central incisor in the other. One of our patients had a Thr1052Met mutation, holoprosencephaly-like facial features, and a normal MRI. Ming et al. [(2002); Hum Genet 110:297-301] reported an identical mutation, but with alobar holoprosencephaly.     

Holoprosencephaly in an infant with a minute deletion of chromosome 21(q22.3)

We evaluated an infant because holoprosencephaly had been detected by prenatal ultrasound examination and magnetic resonance imaging (MRI). Postnatally, high-resolution cytogenetic studies showed a minute deletion of chromosome 21(q22.3). This patient lacks many of the characteristics associated with monosomy 21, partial monosomy 21, and ring 21 chromosome patients. She also lacks the midline facial abnormalities often seen with holoprosencephaly. The similarity in facial appearance between this case and one previously reported patient with holoprosencephaly and a ring chromosome 21 suggests a causal relationship between holoprosencephaly and deletion of chromosome 21(q22.3). These findings also suggest that infants and children with developmental delay and apparently normal facial appearance should be examined for holoprosencephaly and that all identified patients with holoprosencephaly need high-resolution cytogenetic studies with careful attention to the terminal portion of 21q.     

Palate structure in human holoprosencephaly correlates with the facial malformation and demonstrates a new palatal developmental field

In this study we analyzed palate structure in holoprosencephaly and correlated it with the facial malformations. Eleven human holoprosencephalic fetuses (three cyclopic, two ethmocephalic, one cebocephalic, four with median cleft lip, and one with short philtrum) at 17–23 weeks of gestation and three children (age 2½, 6 and 7 years) with a single central incisor were studied. Photographic and radiographic methods were used. We found that in holoprosencephaly palate structure is abnormal. The severity of this malformation decreases with decreasing severity of facial malformation. Thus, the study shows a close relationship between the facial and the palatal malformation. In all phenotypes the premaxillary area is malformed. From this region, a fan-shaped field along the midpalatal suture is involved in all facial phenotypes, the fan being broadest in cyclopia and narrowest in the short philtrum malformation. A similar fan-shaped field can be discerned in the face, where the broadest fan also indicates the greatest severity with cyclopia, and the narrowest fan the least severe median lip malformation. In the palate field, the anteroposterior furrows seemingly demarcate the field. The findings may be of importance for the future evaluation of palatal malformations in children. Am. J. Med. Genet. 73:387–392, 1997. © 1997 Wiley-Liss, Inc.     

Recurrence of holoprosencephaly in families with a positive history

A holoprosencephalic child was born into a family with 6 other affected members in 3 generations. A chromosome study of the proband was normal. The recurrence risk of holoprosencephaly was 22% in first degree relatives of affected individuals in this family. The recurrence risk was 22.9% for holoprosencephaly and 34.3% for holoprosencephaly and facial and neural defects when families with affected members in the medical literature in two generations were added. Dominant inheritance with reduced penetrance in family members best explains the inheritance pattern of familial holoprosencephaly.     

Nasal Septal and Premaxillary Developmental Integration: Implications for Facial Reduction in Homo

The influence of the chondrocranium in craniofacial development and its role in the reduction of facial size and projection in the genus Homo is incompletely understood. As one component of the chondrocranium, the nasal septum has been argued to play a significant role in human midfacial growth, particularly with respect to its interaction with the premaxilla during prenatal and early postnatal development. Thus, understanding the precise role of nasal septal growth on the facial skeleton is potentially informative with respect to the evolutionary change in craniofacial form. In this study, we assessed the integrative effects of the nasal septum and premaxilla by experimentally reducing facial length in Sus scrofa via circummaxillary suture fixation. Following from the nasal septal‐traction model, we tested the following hypotheses: (1) facial growth restriction produces no change in nasal septum length; and (2) restriction of facial length produces compensatory premaxillary growth due to continued nasal septal growth. With respect to hypothesis 1, we found no significant differences in septum length (using the vomer as a proxy) in our experimental (n = 10), control (n = 9) and surgical sham (n = 9) trial groups. With respect to hypothesis 2, the experimental group exhibited a significant increase in premaxilla length. Our hypotheses were further supported by multivariate geometric morphometric analysis and support an integrative relationship between the nasal septum and premaxilla. Thus, continued assessment of the growth and integration of the nasal septum and premaxilla is potentially informative regarding the complex developmental mechanisms that underlie facial reduction in genus Homo evolution. Anat Rec, 2010. © 2010 Wiley‐Liss, Inc.     

Holoprosencephaly and trisomy 21 in a child born to a nondiabetic mother

This is the second reported case of a child with holoprosencephaly and trisomy 21. The first case was born to a diabetic woman; in our case, there was no evidence of diabetes in the mother. Most of the distinctive facial features of Down syndrome were obscured by the presence of cyclopia and a supraorbital proboscis in this infant. The relevance of chromosome analysis in cases with holoprosencephaly is discussed.     

Photo-evoked eyelid microvibration in newborn infants and children--reflex arc and maturational change

We studied maturational process of the photo-evoked eyelid microvibration (PEMV) in 166 newborns, 72 children and 10 adults free of any neurologic disorders. The results indicate that the latency of PEMV shortens during growth due to the myelination of the nerve fibers of the involved pathway. Age-related normal values were established. The pathway of PEMV probably consists of retina, optic nerve, pretectum, facial nerve, and orbicularis oculi muscle. We also evaluated the effect on this reflex of retinoblastoma, facial nerve paralysis, holoprosencephaly anomalad, and a muscle relaxant used for artificial respiration in respiratory distress syndrome.     

Holoprosencephaly as a possible embryonic alcohol effect

Three mothers of infants with holoprosencephaly consumed alcohol heavily in pregnancy. We postulate that early alcohol exposure is a possible cause of their malformation. The 3 mothers consumed alcohol only in the first trimester but the first mother continued to take chlordiazepoxide and imipramine throughout the pregnancy. Her infant had an alobar holoprosencephaly associated with a median cleft lip, ocular hypotelorism, and a flat nose. The other infants had semilobar holoprosencephaly and hydrocephalus. These latter 2 infants did not show the characteristic facies of the fetal alcohol syndrome. G-band chromosome studies were normal in all 3 infants. The association of holoprosencephaly with alcohol exposure during pregnancy in humans has been mentioned only briefly, although this malformation has been induced by alcohol in animals. These 3 infants may support the hypothesis that acute or subacute heavy alcohol exposure early in pregnancy could lead to holoprosencephaly without the necessity of a chronic alcohol exposure and without necessarily causing the typical facial findings of the fetal alcohol syndrome.     

Holoprosencephaly: Epidemiologic and clinical characteristics of a California population

Holoprosencephaly is a brain defect resulting from incomplete cleavage of the embryonic forebrain. It involves forebrain and facial malformations that can range from mild to severe. The epidemiology of holoprosencephaly is largely unknown. Published prevalence estimates have been derived from clinic-based case series, and suggested risk factors for holoprosencephaly have been identified in case reports, without confirmation from systematically conducted population-based studies. Using data from a population-based birth defects registry in California, we describe the epidemiologic and clinical characteristics of cytogenetically and phenotypically distinct types of holoprosencephaly. A total of 121 cases was identified among a cohort of 1,035,386 live births and fetal deaths. The prevalence of holoprosencephaly was 1.2 per 10,000 births (95% confidence interval 1.0–1.4 per 10,000). Of all cases, 41% (50/121) had a chromosomal abnormality, most commonly Trisomy 13. Among the 71 cytogenetically apparently normal cases, 18 had recognizable syndromes and the remaining 53 were of unknown cause. Among the cytogenetically abnormal cases, females had a greater risk than males (odds ratio = 2.3, 95% confidence interval [1.2, 4.4]). Among the cytogenetically normal cases, increased risks were observed among Hispanic whites (OR = 1.8 [0.9, 3.6]) and cases whose mother was born in Mexico (OR = 2.2 [1.0, 4.5]). Approximately 46% of all cases had alobar holoprosencephaly, the most severe form of the forebrain malformation. The facial phenotype did not strongly predict the severity of the brain defect; however, severity was inversely correlated with length of survival. This study is the first to present findings based on such a large population-based series of infants/fetuses affected by holoprosencephaly, and demonstrates the importance of investigating the component subgroups of this rare phenotype. © 1996 Wiley-Liss, Inc.     

Holoprosencephaly and primary craniosynostosis: The Genoa syndrome

We report on 2 sibs with holoprosencephaly of the semilobar type, unusual facial appearance not diagnostic of holoprosencephaly, and primary craniosynostosis involving the coronal and lambdoid sutures. The condition represents a newly recognized syndrome, possibly having autosomal recessive inheritance. © 1993 Wiley-Liss, Inc.     

Holoprosencephaly, hypertelorism, and ectrodactyly in a boy with an apparently balanced de novo t(2;4) (q14.2;q35)

A holoprosencephaly, hypertelorism, and ectrodactyly syndrome (HHES) was described in three previous cases in whom chromosomes were apparently normal. We report on a 3-year-old boy with HHES and a de novo apparently balanced t(2;4)(q14.2;q35) confirmed by fluorescent in situ hybridization. He had severe growth and mental retardation, lobar holoprosencephaly, hypertelorism, microphthalmos, and iris, choroid, and retina colobomata. Less-severe facial involvement correlates with the semilobar type of holoprosencephaly; limb defects consisted of foot ectrodactyly and syndactyly. All previous HHES cases were sporadic and of unknown cause. A cryptic imbalance secondary to the translocation (2;4) in our patient may explain the phenotype.     

Occurrence of cyclopia, myelomeningocele, deafness, and abducens paralysis in siblings

As holoprosencephaly without chromosome defect may be associated with other CNS-related anomalies such as mental retardation, mental illness, facial paralysis, endocrine disorders, deafness, spina bifida, and myelomeningocele, we present a family in which one girl had a myelomeningocele, a brother had orbital hypotelorism, facial and cerebral asymmetries, cerebral palsy, abducens paralysis, and inner ear deafness. A 3rd pregnancy was terminated at 16 weeks; the fetus had cyclopia. A common cause is discussed in these cases and in those families in which holoprosencephaly and additional malformations occur among different generations.     

Patterns of orofacial clefting in the facial morphology of bats: a possible naturally occurring model of cleft palate

A normal feature of the facial anatomy of many species of bat is the presence of bony discontinuities or clefts, which bear a remarkable similarity to orofacial clefts that occur in humans as a congenital pathology. These clefts occur in two forms: a midline cleft between the two premaxillae (analogous to the rare midline craniofacial clefts in humans) and bilateral paramedian clefts between the premaxilla and the maxillae (analogous to the typical cleft lip and palate in humans). Here, we describe the distribution of orofacial clefting across major bat clades, exploring the relationship of the different patterns of clefting to feeding mode, development of the vomeronasal organ, development of the nasolacrimal duct and mode of emission of the echolocation call in different bat groups. We also present the results of detailed radiographic and soft tissue dissections of representative examples of the two types of cleft. The midline cleft has arisen independently multiple times in bat phylogeny, whereas the paramedian cleft has arisen once and is a synapomorphy uniting the Rhinolophidae and Hipposideridae. In all cases examined, the bony cleft is filled in by a robust fibrous membrane, continuous with the periosteum of the margins of the cleft. In the paramedian clefts, this membrane splits to enclose the premaxilla but forms a loose fold laterally between the premaxilla and maxilla, allowing the premaxilla and nose‐leaf to pivot dorsoventrally in the sagittal plane under the action of facial muscles attached to the nasal cartilages. It is possible that this is a specific adaptation for echolocation and/or aerial insectivory. Given the shared embryological location of orofacial clefts in bats and humans, it is likely that aspects of the developmental control networks that produce cleft lip and palate in humans may also be implicated in the formation of these clefts as a normal feature in some bats. A better understanding of craniofacial development in bats with and without clefts may therefore suggest avenues for research into abnormal craniofacial development in humans.     

Holoprosencephaly,hypertelorism, and ectrodactyly in a boy with an apparently balanced de novo t(2;4)(q14.2;q35)

A holoprosencephaly, hypertelorism, and ectrodactyly syndrome (HHES) was described in three previous cases in whom chromosomes were apparently normal. We report on a 3‐year‐old boy with HHES and a de novo apparently balanced t(2;4)(q14.2;q35) confirmed by fluorescent in situ hybridization. He had severe growth and mental retardation, lobar holoprosencephaly, hypertelorism, microphthalmos, and iris, choroid, and retina colobomata. Less‐severe facial involvement correlates with the semilobar type of holoprosencephaly; limb defects consisted of foot ectrodactyly and syndactyly. All previous HHES cases were sporadic and of unknown cause. A cryptic imbalance secondary to the translocation (2;4) in our patient may explain the phenotype. Am. J. Med. Genet. 90:423–426, 2000 © 2000 Wiley‐Liss, Inc.     

Holoprosencephaly: variation of expression in face and brain in three sibs.

A family is described containing three sibs with holoprosencephaly. They showed a striking diversity of both cerebral and facial abnormalities. Autosomal recessive inheritance seems most likely. Because of the great variety in expression of this disorder, it is of importance for genetic counselling to examine both sibs and parents.     

A re-evaluation of the premaxillary bone in humans

The discovery of the premaxillary bone (os incisivum, os intermaxillare or premaxilla) in humans has been attributed to Goethe, and it has also been named os Goethei. However, Broussonet (1779) and Vicq dAzyr (1780) came to the same result with different methods. The first anatomists described this medial part of the upper jaw as a separate bone in the vertebrate skull, and, as we know, Coiter (1573) was the first to present an illustration of the sutura incisiva in the human. This fact, and furthermore its development from three parts:—(1) the alveolar part with the facial process, (2) the palatine process, and (3) the processus Stenonianus—can no longer be found in modern textbooks of developmental biology. At the end of the nineteenth and in the early twentieth century a vehement discussion focused on the number and position of its ossification centers and its sutures. Therefore, it is hard to believe that the elaborate work of the old embryologists is ignored and that the existence of a premaxillary bone in humans is even denied by many authors. Therefore this re-evaluation was done to demonstrate the early development of the premaxillary bone using the reconstructions of Felber (1919), Jarmer (1922) and data from our own observations on SEM micrographs and serial sections from 16 mm embryo to 68 mm fetus. Ossification of a separate premaxilla was first observed in a 16 mm embryo. We agree with Jarmer (1922), Peter (1924), and Shepherd and McCarthy (1955) that it develops from three anlagen, which are, however, not fully separated. The predominant sutura incisiva (rudimentarily seen on the facial side in a prematurely born child) and a shorter sutura intraincisiva argue in this sense. The later growth of this bone and its processes establish an important structure in the middle of the facial skull. Its architecture fits well with the functional test of others. We also focused on the relation of the developing premaxilla to the forming nasal septum moving from ventral to dorsal and the intercalation of the vomer. Thus the premaxilla acts as a stabilizing element within the facial skeleton comparable with the keystone of a Roman arch. Furthermore, the significance of the premaxillary anlage for the closure of the palatine was documented by a synopsis made from a stage 16, 10.2 mm GL embryo to a 49 mm GL fetus. Finally the growth of the premaxilla is closely related to the development of the human face. Abnormal growth may be correlated to characteristic malformations such as protrusion, closed bite and prognathism. Concerning the relation of the premaxillary bone to cleft lip and palate we agree with others that the position of the clefts is not always identical with the incisive suture. This is proved by the double anlagen of an upper–outer incisor in a 55 mm fetus and an adult.     

Morphological variability in unrepaired bilateral clefts with and without cleft palate evaluated with geometric morphometrics

In subjects with orofacial clefts, there is an unresolved controversy on the effect of congenital maxillary growth deficiency vs. the effect of surgical intervention on the outcome of treatment. Intrinsic growth impairment in subjects with orofacial clefts can be studied by comparing facial morphology of subjects with untreated cleft and unaffected individuals of the same ethnic background. Bilateral cleft lip and palate is the most severe and least prevalent form of the orofacial cleft. The aim of this study was to compare facial morphology in subjects with unrepaired complete bilateral clefts and unaffected controls using geometric morphometrics. Lateral cephalograms of 39 Indonesian subjects with unrepaired bilateral complete cleft lip and alveolus (mean age: 24 years), or unrepaired bilateral complete cleft lip, alveolus, and palate (mean age: 20.6 years) and 50 age and ethnically matched controls without a cleft (25 males, 25 females, mean age: 21.2 years) were digitized and traced and shape variability was explored using principal component analysis, while differences between groups and genders were evaluated with canonical variate analysis. Individuals with clefts had a more pronounced premaxilla than controls. Principal component analysis showed that facial variation in subjects with clefts occurred in the anteroposterior direction, whereas in controls it was mostly in the vertical direction. Regression analysis with group, sex, and age as covariates and principal components from 1 to 6 as dependent variables demonstrated a very limited effect of the covariates on the facial shape variability (only 11.6% of the variability was explained by the model). Differences between cleft and non-cleft subjects in the direction of facial variability suggest that individuals with bilateral clefts can have an intrinsic growth impairment affecting facial morphology later in life.