Robin sequence without cleft palate: Genetic diagnoses and management implications

Robin sequence (RS), the triad of micrognathia, glossoptosis, and airway obstruction, is a major cause of respiratory distress and feeding difficulties in neonates. Robin sequence can be associated with other medical or developmental comorbidities in ~50% of cases (“syndromic” RS). As well, RS is variably associated with cleft palate (CP). Previous studies have not investigated differences in clinical characteristics of children with RS based on presence or absence of CP. We retrospectively reviewed 175 children with RS and compared genetic diagnoses, medical and developmental comorbidities, severity of airway obstruction, and feeding outcomes between those with and without CP. Strikingly, 45 of 45 (100%) children with RS without CP were classified as syndromic due to presence of comorbidities unrelated to RS, while 83 of 130 (64%) children with RS with CP were classified as syndromic. Among 128 children with syndromic RS, there were no differences in severity of airway obstruction, surgical intervention rate or type, or feeding outcome at 12 months based on CP status. Our findings support the conclusion that the pathogenesis of RS without CP is distinct from RS with CP and more likely to cause additional medical or developmental problems. Alternatively, children with RS without CP and without additional anomalies present may be under recognized.     

Molecular Mechanisms Leading to Null‐Protein Product from Retinoschisin (RS1) Signal‐Sequence Mutants in X‐Linked Retinoschisis (XLRS) Disease

Retinoschisin (RS1) is a cell‐surface adhesion molecule expressed by photoreceptor and bipolar cells of the retina. The 24‐kDa protein encodes two conserved sequence motifs: the initial signal sequence targets the protein for secretion while the larger discoidin domain is implicated in cell adhesion. RS1 helps to maintain the structural organization of the retinal cell layers and promotes visual signal transduction. RS1 gene mutations cause X‐linked retinoschisis disease (XLRS) in males, characterized by early‐onset central vision loss. We analyzed the biochemical consequences of several RS1 signal‐sequence mutants (c.1A>T, c.35T>A, c.38T>C, and c.52G>A) found in our subjects. Expression analysis in COS‐7 cells demonstrates that these mutations affect RS1 biosynthesis and result in an RS1 null phenotype by several different mechanisms. By comparison, discoidin‐domain mutations generally lead to nonfunctional conformational variants that remain trapped inside the cell. XLRS disease has a broad heterogeneity in general, but subjects with the RS1 null‐protein signal‐sequence mutations are on the more severe end of the clinical phenotype. Results from the signal‐sequence mutants are discussed in the context of the discoidin‐domain mutations, clinical phenotypes, genotype–phenotype correlations, and implications for RS1 gene replacement therapy. Hum Mutat 31:1251–1260, 2010. Published 2010 Wiley‐Liss, Inc.     

Lung hypoplasia in a patient with del(2)(q33‐q35) demonstrated by chromosome microdissection

We report on a 17‐month‐old girl with multiple malformations, including lung hypoplasia, multiple ventricular septal defects, craniofacial anomalies, and malrotation of the intestine. Moreover, the patient showed Robin sequence, developmental delay, as well as pre‐ and postnatal growth retardation. Postnatal cytogenetic analysis revealed an interstitial deletion on the long arm of chromosome 2. Microdissection and reverse chromosome painting of the aberrant chromosome 2 as well as FISH with a panel of chromosome 2q band‐specific YACs mapped the deletion to 2q33‐q35. Lung hypoplasia has not been described so far in patients with del(2)(q33‐q35). A review of previously reported patients showed variable phenotypes apparently due to different deleted chromosomal segments. Am. J. Med. Genet. 94:184–188, 2000. © 2000 Wiley‐Liss, Inc.     

Resolving clinical diagnoses for syndromic cleft lip and/or palate phenotypes using whole‐exome sequencing

Individuals from three families ascertained in Bogota, Colombia, showing syndromic phenotypes, including cleft lip and/or palate, were exome‐sequenced. In each case, sequencing revealed the underlying causal variation confirming or establishing diagnoses. The findings include very rare and novel variants providing insights into genotype and phenotype relationships. These include the molecular diagnosis of an individual with Nager syndrome and a family exhibiting an atypical incontinentia pigmenti phenotype with a missense mutation in IKBKG. IKBKG mutations are typically associated with preterm male death, but this variant is associated with survival for 8–15 days. The third family exhibits unusual phenotypic features and the proband received a provisional diagnosis of Pierre Robin sequence (PRS). Affected individuals share a novel deleterious mutation in IRF6. Mutations in IRF6 cause Van der Woude and popliteal pterygium syndrome and contribute to nonsyndromic cleft lip phenotypes but have not previously been associated with a PRS phenotype. Exome sequencing followed by in silico screening to identify candidate causal variant(s), and functional assay in some cases offers a powerful route to establishing molecular diagnoses. This approach is invaluable for conditions showing phenotypic and/or genetic heterogeneity including cleft lip and/or palate phenotypes where many underlying causal genes have not been identified.     

Richieri-Costa-Pereira syndrome: a unique acrofacial dysostosis type. An overview of the Brazilian cases

We reported on 16 new Brazilian patients and review findings in 12 previously reported cases (25 apparently unrelated Brazilian families) from Hospital of Rehabilitation of Craniofacial Anomalies, presenting with Richieri‐Costa–Pereira syndrome. All patients display a unique pattern of anomalies consisting of microstomia, micrognathia, abnormal fusion of mandible, cleft palate/Robin sequence, absence of central lower incisors, minor ears anomalies, hypoplastic first ray, abnormal tibiae, hypoplastic halluces, and clubfeet. Learning disability was also a common finding. The sex‐ratio showed deviation toward to female (1.8F:1M). Recurrence in sibs was observed in nine instances and consanguinity in 11, supporting the hypothesis of autosomal recessive inheritance. Nineteen of the 25 families lived in São Paulo State, seven of them (10 affected individuals) from an isolated region named “Vale do Ribeira.” The geographic barrier of this region associated with the high incidence of the consanguineous matting suggested that this condition is caused by a rare mutation with a founder effect. With the exception of one patient in France, all known cases are of Brazilian origin. The causative gene of this rare syndrome remains unknown. © 2010 Wiley‐Liss, Inc.     

Modulation of Diabetes‐Induced Palate Defects by Maternal Immune Stimulation

Maternal diabetes can induce a number of developmental abnormalities in both laboratory animals and humans, including deformities of the face and palate. The incidence of birth defects in newborns of women with diabetes is approximately 3 to 5 times higher than among nondiabetics. In mice, nonspecific activation of the maternal immune system can reduce fetal abnormalities caused by various etiologies including hyperglycemia. This study was conducted to determine whether nonspecific maternal immune stimulation could reduce diabetes‐induced palate defects and orofacial clefts. Female ICR mice were immune stimulated before induction of hyperglycemia with Freund's complete adjuvant (FCA), granulocyte‐macrophage colony‐stimulating factor (GM‐CSF), or interferon‐γ (IFNγ). Streptozocin was used to induce hyperglycemia (26–35 mmol blood glucose) in females before breeding. Fetuses from 12 to 18 litters per treatment group were collected on Day 17 of gestation. Palate width and length were measured, and the incidence of orofacial clefts was determined. Palate length and width were both decreased by maternal hyperglycemia. Maternal immune stimulation with GM‐CSF or FCA limited the degree of palate shortening from the hyperglycemia. Each of the three immune stimulants attenuated significant narrowing of the palate. Rates of orofacial clefts were not significantly different between treatment groups. Palatogenesis is a complex process driven by cellular signals, which regulate cell growth and apoptosis. Dysregulation of cellular signals by maternal hyperglycemia can result in fetal malformations. Maternal immune stimulation may prevent dysregulation of these signaling pathways thus reducing fetal malformations and normalizing palate growth. Anat Rec 2009. © 2008 Wiley‐Liss, Inc.     

A Comprehensive Study of Palate Development in Miniature Pig

Palate development is an important morphogenetic event in facial development, including the fusion of the lateral and medial nasal portions of the frontonasal process and maxilla. Derailments of any of these events may result in cleft palate, the most frequent congenital craniofacial abnormality. Recent research has shown that the microanatomy of the miniature pig oral maxillofacial region is quite similar to that of humans, and the use of miniature pigs as a large animal model for dental and orofacial research is increasing. Little information is available, however, about the development of the miniature pig palate. Here, using histological and ultrastructural methods, we describe the developmental stages of the palate in miniature pigs. Sections from E26, E30, E35, E40, E45, and E50 embryos were stained with hematoxylin–eosin, and selected specimens were also processed for electron microscopy. The development of the miniature pig palate can be divided into four stages: growth of the bilateral palatal shelves alongside the tongue at E30; elevation of the horizontal position above the tongue at E35; establishment of bilateral shelf contact at the midline from E35–50; and a final fusion step at E50, similar to the mouse and human. The histological characteristics of the miniature pig palate at different developmental stages were synchronously verified at the ultrastructural level. Our study provides a piece of first‐hand data regarding palate morphological organogenesis in the miniature pig and a foundation for further research with this model to explore mechanisms of cleft palate development. Anat Rec, 300:1409–1419, 2017. © 2017 Wiley Periodicals, Inc.     

Toriello‐Carey syndrome: Case report with additional findings

Toriello‐Carey syndrome comprises agenesis of the corpus callosum, telecanthus, small palpebral fissures, Pierre Robin sequence, abnormal ears, nuchal laxity and cardiac defects. We report on a female patient who has some additional findings including an anteriorly placed anus. This anomaly adds to the list of other midline anomalies seen in this syndrome. We compare the findings to those seen in the Opitz BBBG syndrome, a well‐defined syndrome of the midline developmental field. Our patient, having a severe manifestation of complicated congenital heart disease, died in the neonatal period, which argues against the likelihood that this is an X‐linked disorder with more severe manifestations in males. © 2001 Wiley‐Liss, Inc.     

Prenatal diagnosis of micrognathia in 41 fetuses: Retrospective analysis of outcome and genetic etiologies

Fetal micrognathia can be detected early in pregnancy. Prognosis of micrognathia depends on the risk of respiratory distress at birth and on the long‐term risk of intellectual disability. The purpose of this study was to evaluate the long‐term prognosis of fetuses with prenatal diagnosis of micrognathia by estimating the prevalence and the severity of confirmed genetic diagnosis in our cohort. Our retrospective study included 41 fetuses with prenatal diagnosis of micrognathia referred to the multidisciplinary centers for prenatal diagnosis in Nice and Marseille, France, between 2006 and 2016. Fetal micrognathia was associated with cleft palate in 27 cases. A genetic cause was confirmed in 21 cases (67%). A chromosomal abnormality was present in 12 cases, including three copy‐number variations diagnosed by array CGH. Monogenic disorders were identified in nine cases, most often after birth. Fetuses with family history of micrognathia or Pierre Robin sequence had a favorable outcome. Prognosis was good for the fetuses without associated findings and normal chromosomal analysis, with the exception of one case with a postnatal diagnosis of mandibulofacial dysostosis with microcephaly. Prognostic was poor for the fetuses with additional ultrasound anomalies, as only 5 out of 28 children had a good outcome. Prenatal diagnosis of micrognathia is an indicator of a possible fetal pathology justifying multidisciplinary management. Our study confirms the necessity of performing prenatal array CGH. Use of high‐throughput gene sequencing in prenatal period could improve diagnostic performance, prenatal counseling, and adequate postnatal care.     

Toriello-Carey syndrome: Evidence for X-linked inheritance

Toriello-Carey syndrome is characterized by agenesis of the corpus callosum, telecanthus, short palpebral fissures, Robin sequence, abnormal ears, cardiac anomalies, and hypotonia. We describe two patients with Toriello-Carey syndrome and call attention to an unbalanced sex ratio. The first patient, a male, was born at term by Cesarean section and manifests micrognathia, cleft soft palate, hypoplastic right ear, anotia on the left side, cerebellar vermis hypoplasia, hydrocephalus, agenesis of the corpus callosum, and hypoplastic left heart. He died 2 days after birth. The second patient is the male sib of a patient reported previously [Am J Med Genet 42: 374–376; 1992]. He had large fontanelles, telecanthus, a short nose, small and malformed ears, micrognathia, a large ventricular septal defect, and pulmonary stenosis. At age 8 months he has growth retardation and developmental delay. A sister is unaffected. Review documented eight other patients with Toriello-Carey syndrome, six of whom were male. The two female patients are less severely affected and are still alive. Of the other male patients, all are deceased except one who is still alive at age 5 years; he has severe growth retardation (-3 SD), mental retardation (DQ44), severe speech delay, and characteristic anomalies. The predominance of affected males and the milder phenotype in the female patients suggests an X-linked gene or sex influenced gene. © 1996 Wiley-Liss, Inc.     

Molecular diversity of peanut‐nodulating rhizobia in soils of Argentina

RSα sequencing is a valuable tool for identification of bacterial strains, and for evaluating the genetic structure of indigenous rhizobial populations. The purpose of this study was to evaluate, qualitatively, the presence or absence of RSα fragment in peanut‐nodulating strains isolated from plants grown at four sites in central Argentina. RSα fragment was found in only three of 26 indigenous strains, and in one of three inoculant strains analyzed. In contrast to results from studies of other symbiotic nitrogen‐fixing bacteria, such as soybean‐nodulating strains, no correlation was found between generation time and presence of RSα sequence. Phylogenetic analysis of the 16S rRNA gene sequence grouped peanut‐nodulating strains into two clusters, Bradyrhizobium japonicum vs. B. elkanii, and showed divergence among strains positive for RSα sequence. Our results confirm the genetic diversity previously reported for various peanut‐nodulating rhizobial strains, and indicate that the RSα fragment is not applicable as a marker or tool for competition assays at the field or ecological level. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Velo-cardio-facial phenotype and deletion of 22q11.2 in Hungarian children

Velo-cardio-facial syndrome is a developmental disorder characterized by heart defects, specific facial features, cleft palate and learning disability. Most patients have a 3-Mb deletion in chromosomal region 22q11.2. This microdeletion has also been found in patients with isolated conotruncal malformations. Although no significant ethnic variability has been reported in the frequency 22q11.2 deletions, some recent studies question the high frequency of this as the underlying cause of velo-cardio-facial syndrome in Anglo-American populations. A screening program was initiated, including a detailed clinical assessment, followed by fluorescence in situ hybridization studies for microdeletion 22q11.2 in 24 children with congenital cardiac malformations referred consecutively to our genetics clinic. We found a high ratio of associated findings including cleft palate and developmental delay in our patient group. The clinical diagnosis of velo-cardio-facial syndrome was established in 8 patients. However, the common deletion was detected in only two children. We conclude that, although the 'velo-cardio-facial phenotype' appears to be common in Hungarian children with congenital cardiac malformations, many patients may have different etiologies other than del(22)(q11.2).     

Inhibition of food intake induced by acute stress in rats is due to satiation effects

Acute mild stress induces an inhibition of food intake in rats. In most studies, the cumulative daily food intake is measured but this only provides a quantitative assessment of ingestive behavior. The present study was designed to analyze the reduction in food intake induced by acute stress and to understand which behavioral and central mechanisms are responsible for it. Two different stressors, restraint stress (RS) and forced swimming stress (FSS), were applied acutely to male Wistar rats. We first measured corticosterone and ACTH in plasma samples collected immediately after acute RS and FSS in order to validate our stress models. We measured food intake after RS and FSS and determined meal patterns and behavioral satiety sequences. The expressions of CRF, NPY and POMC in the hypothalamus were also determined immediately after acute RS and FSS. The rise in corticosterone and ACTH levels after both acute RS and FSS validated our models. Furthermore, we showed that acute stress induced a reduction in cumulative food intake which lasted the whole day for RS but only for the first hour after FSS. For both stressors, this stress-induced food intake inhibition was explained by a decrease in meal size and duration, but there was no difference in ingestion speed. The behavioral satiety sequence was preserved after RS and FSS but grooming was markedly increased, which thus competed with, and could reduce, other behaviors, including eating. Lastly, we showed that RS induced an increase in hypothalamic POMC expression. These results suggest that acute stress may affect ingestive behavior by increasing satiation and to some extent by enhancing grooming, and this may be due to stimulation of the hypothalamic POMC neurons.     

Gene/environment causes of cleft lip and/or palate

Craniofacial anomalies, and in particular cleft lip and palate, are major human birth defects with a worldwide frequency of 1 in 700 and substantial clinical impact. A wide range of studies in developmental biology has contributed to a better knowledge of how both genes and environmental exposures impact head organogenesis. Specific causes have now been identified for some forms of cleft lip and palate, and we are at the beginning of a time in which the common nonsyndromic forms may also have specific etiologies identified. Mouse models have an especially important role in disclosing cleft etiologies and providing models for environmental cotriggers or interventions. An overview of the gene-environment contributions to nonsyndromic forms of clefting and their implications for developmental biology and clinical counseling is presented.     

Recessive multiple epiphyseal dysplasia – Clinical characteristics caused by rare compound heterozygous SLC26A2 genotypes

Pathogenic sequence variants in the solute carrier family 26 member 2 (SLC26A2) gene result in lethal (achondrogenesis Ib and atelosteogenesis II) and non-lethal (diastrophic dysplasia and recessive multiple epiphyseal dysplasia, rMED) chondrodysplasias. We report on two new patients with rMED and very rare compound heterozygous mutation combinations in non-consanguineous families. Patient I presented in childhood with waddling gait and joint stiffness. Radiographs showed epiphyseal changes, bilateral coxa plana–deformity and knee valgus deformity, for which he underwent surgeries. At present 33 years his height is 165 cm. Patient II presented with cleft palate, small jaw, short limbs, underdeveloped thumbs and on radiographs, cervical kyphosis with an underdeveloped C4. He also developed severe scoliosis but has grown at −2.9 SD curve. Molecular analysis revealed that patient I is heterozygous for two known pathogenic variants in SLC26A2, a splice site variant c.-26+2T > C and a missense variant c.1957T > A (p.Cys653Ser), while patient II is compound heterozygous for missense variants c.835C > T (p.Arg279Trp) and c.1535C > A (p.Thr512Lys). These patients further elucidate the variability of the phenotypic and genetic presentations of rMED.     

Temperament, anxiety, and the processing of threat-relevant stimuli.

This article discusses converging evidence from developmental, clinical, and cognitive psychology suggesting that there is significant overlap between research findings on affect, temperament, and attentional processes associated with pathological anxiety. We offer a proposal for the integration of these 3 areas aimed at developing a more clear understanding of the developmental sequence and operative mechanisms in the dysregulation of negative affect and the development of symptoms of anxiety pathology. We review evidence for a model indicating that reactive and effortful temperamental processes, possibly mediated by an attentional bias toward threat-relevant information, interact to produce problems of dysregulated negative affect and elevated levels of pathological anxiety. This model may assist in understanding the development of anxiety disorders, identifying children at risk for such disorders, and selecting points of entry for both preventative and curative interventions.     

Developmental outcome in Pierre Robin sequence: A longitudinal and prospective study of a consecutive series of severe phenotypes

Pierre Robin sequence (PRS) is a congenital condition with a heterogeneous and imprecise developmental prognosis. We conducted a longitudinal prospective study analyzing the long‐term developmental outcome of a consecutive series of 39 children with PRS who had an a priori good prognosis (isolated PRS or PRS associated with a Stickler syndrome) but severe neonatal disorders (respiratory and feeding difficulties). Psychomotor and cognitive levels, speech, and eating behavior were assessed at 15 months of age and 3 and 6 years of age; 24 of the oldest children were interviewed at age 11 or 12 years. Results were analyzed by diagnosis, extent of respiratory and feeding disorders, and treatment modalities. Cognitive scores were within normal ranges and increased over time, from 90.5 at 15 months of age to 109.1 at 6 years. The 24 oldest children were enrolled in the appropriate junior high school grade at the normal age. For children 15 months of age, language scores were below the average, as were scores for vocabulary at 3 years for half of the patients. At 6 years, children's speech showed persistent rhinolalia, which was mild (47%), moderate (11%), or major (11%). At 15 months of age, 74% of the children had satisfactory eating behavior, and 15% had serious difficulties. At 3 and 6 years, 18% and 6% of the children, respectively, had eating problems. Treatment modalities had no significant effect on long‐term outcome. Global developmental quotient scores were lower but not significantly for children with an associated Stickler syndrome than those with isolated PRS. Children with isolated PRS showed good prognosis. © 2013 Wiley Periodicals, Inc.     

Long-term survival in TARP syndrome and confirmation of RBM10 as the disease-causing gene

TARP syndrome, comprising Talipes equinovarus, atrial septal defect (ASD), Robin sequence (micrognathia, glossoptosis, and cleft palate), and persistence of the left superior vena cava, is an X-linked condition with pre- or postnatal lethality in affected males. Based on linkage studies and massively parallel sequencing of X-chromosome exons in two families, the disease-causing gene was identified as RBM10. We identified a maternally inherited frameshift mutation in an unrelated patient, confirming RBM10 as the disease gene. This is the first reported individual with TARP syndrome who survived past early infancy, thus expanding the phenotypic spectrum of this disorder. In addition to the characteristic cleft palate, ASD, and persistent superior vena cava, he had low-set and posteriorly angulated ears, upslanting palpebral fissures, cryptorchidism, and structural brain abnormalities including partial agenesis of the corpus callosum, dysplastic enlarged caudate, and cerebellar hypoplasia with megacisterna magna. Preterm delivery, suspected pulmonary hypoplasia, and pulmonary hypertension resulted in chronic lung disease. At the age of 3(7)/(12) years, he remained ventilator-dependent at night, and he was fed exclusively through a gastro-jejunal tube. Sensorineural hearing loss required a hearing aid. Optic atrophy and cortical visual impairment were noted. He was unable to sit independently, was non-communicative and he had severe intellectual disability. Atrial flutter required recurrent ablation of intra-atrial re-entry pathways. The mother's heterozygosity for the RBM10 mutation underscored the importance of accurate diagnosis and counseling for TARP syndrome.     

Interstitial deletion 4q32‐34 with ulnar deficiency: 4q33 may be the critical region in 4q terminal deletion syndrome

We report on an infant with Robin sequence; mild developmental delay; a left ulnar ray defect with absent ulna and associated metacarpals, carpals and phalanges; and a right ulnar nerve hypoplasia. He had a de novo interstitial deletion of 4q32→q34. The critical region involved in the 4q terminal deletion syndrome may be 4q33. This conclusion was suggested by showing that del(4)(q31qter), del(4)(q32qter), and del(4)(q33qter) result in a similarly severe phenotype. In addition, we propose that genes for distal arm development, in particular for development of the left ulnar ray, central nervous system development, and cleft lip and palate, may be located at 4q33. © 2001 Wiley‐Liss, Inc.     

Catel-Manzke syndrome: a clinical report suggesting autosomal recessive inheritance

We describe a 3-month-old male infant with cleft palate, glossoptosis, micrognathia, and bilateral clinodactyly, an association which is characteristic of Catel-Manzke syndrome. In addition, the patient had ligamentous laxity in the knee which is a rare finding of this syndrome. The mode of inheritance of Catel-Manzke syndrome is unknown. Most cases are thought to be sporadic but the present patient with consanguinity between the parents and a possibly affected sib provide support for autosomal recessive inheritance.