A Comprehensive Craniofacial Study of 22q11.2 Deletion Syndrome.

The 22q11.2 deletion syndrome (22q11.2DS) is one of the most frequent microdeletion syndromes and presents with a highly variable phenotype. In most affected individuals, specific but subtle facial features can be seen. In this observational study, we aim to investigate the craniofacial and dental features of 20 children with a confirmed diagnosis of 22q11.2DS by analyzing 3-dimensional (3D) facial surface scans, 2-dimensional (2D) clinical photographs, panoramic and cephalometric radiographs, and dental casts. The 3D facial scans were compared to scans of a healthy control group and analyzed using a spatially dense geometric morphometric approach. Cephalometric radiographs were digitally traced, and measurements were compared to existing standards. Occlusal and dental features were studied on dental casts and panoramic radiographs. Interestingly, a general trend of facial hypoplasia in the lower part of the face could be evidenced with the 3D facial analysis in children with 22q11.2DS compared to controls. Cephalometric analysis confirmed a dorsal position of the mandible to the maxilla in 2D and showed an enlarged cranial base angle. Measurements for occlusion did not differ significantly from standards. Despite individual variability, we observed a retruded lower part of the face as a common feature, and we also found a significantly higher prevalence of tooth agenesis in our cohort of 20 children with 22q11.2DS (20%). Furthermore, 3D facial surface scanning proved to be an important noninvasive, diagnostic tool to investigate external features and the underlying skeletal pattern.

Anthropometric and aesthetic outcomes for the nasolabial region in 101 consecutive African children with unilateral cleft lip one year after repair using the anatomical subunit approximation technique.

One hundred and one patients with complete or incomplete cleft lip underwent the anatomical subunit approximation technique for repair. The patients were followed up prospectively for 1year. The objective of this study was to determine the outcomes for the nasolabial area through anthropometric measurements and assessment of the Asher-McDade Aesthetic Index and Steffensen's criteria at 1year after surgery. Six assessors (three cleft surgeons and three non-surgeon medical professionals) examined cropped images; reliability was assessed using Cronbach's alpha. The difference in lip length between the healthy and operated sides was 0.61mm and the difference in nostril diameter was 0.37mm (differences not significant). The average scar width was 2.78±1.35mm. Hypertrophic scars were observed in 9.9% of cases. The average Asher-McDade Aesthetic Index rating varied between 1.35 and 1.98 for all parameters. Cronbach's alpha coefficient was 0.83, 0.89, 0.98, and 0.89 for nasal form, nasal symmetry, vermilion border, and nasolabial profile, respectively. Steffensen's criteria rated appearance as 'good' in 69.3% to 91.1% of cases. The anatomical subunit approximation technique can be performed in Sub-Saharan Africans for all types of unilateral cleft lip. It significantly improves the length of the medial and lateral lips, leaving an acceptable scar. A study with a larger sample size and longer follow-up is warranted.

Pseudoinverse of the Laplacian and best spreader node in a network.

Determining a set of "important" nodes in a network constitutes a basic endeavor in network science. Inspired by electrical flows in a resistor network, we propose the best conducting node j in a graph G as the minimizer of the diagonal element Q_{jj}^{†} of the pseudoinverse matrix Q^{†} of the weighted Laplacian matrix of the graph G. We propose a new graph metric that complements the effective graph resistance R_{G} and that specifies the heterogeneity of the nodal spreading capacity in a graph. Various formulas and bounds for the diagonal element Q_{jj}^{†} are presented. Finally, we compute the pseudoinverse matrix of the Laplacian of star, path, and cycle graphs and derive an expansion and lower bound of the effective graph resistance R_{G} based on the complement of the graph G.

Unified mean-field framework for susceptible-infected-susceptible epidemics on networks, based on graph partitioning and the isoperimetric inequality.

We propose an approximation framework that unifies and generalizes a number of existing mean-field approximation methods for the susceptible-infected-susceptible (SIS) epidemic model on complex networks. We derive the framework, which we call the unified mean-field framework (UMFF), as a set of approximations of the exact Markovian SIS equations. Our main novelty is that we describe the mean-field approximations from the perspective of the isoperimetric problem, which results in bounds on the UMFF approximation error. These new bounds provide insight in the accuracy of existing mean-field methods, such as the N-intertwined mean-field approximation and heterogeneous mean-field method, which are contained by UMFF. Additionally, the isoperimetric inequality relates the UMFF approximation accuracy to the regularity notions of Szemerédi's regularity lemma.

Facial dysmorphism is influenced by ethnic background of the patient and of the evaluator.

The evaluation of facial dysmorphism is a critical step toward reaching a diagnostic. The aim of the present study was to evaluate the ability to interpret facial morphology in African children with intellectual disability (ID). First, 10 experienced clinicians (five from Africa and five from Europe) rated gestalt in 127 African non-Down Syndrome (non-DS) patients using either the score 2 for 'clearly dysmorphic', 0 for 'clearly non dysmorphic' or 1 for 'uncertain'. The inter-rater agreement was determined using kappa coefficient. There was only fair agreement between African and European raters (kappa-coefficient = 0.29). Second, we applied the FDNA Face2Gene solution to assess Down Syndrome (DS) faces. Initially, Face2Gene showed a better recognition rate for DS in Caucasian (80%) compared to African (36.8%). We trained the Face2Gene with a set of African DS and non-DS photographs. Interestingly, the recognition in African increased to 94.7%. Thus, training improved the sensitivity of Face2Gene. Our data suggest that human based evaluation is influenced by ethnic background of the evaluator. In addition, computer based evaluation indicates that the ethnic of the patient also influences the evaluation and that training may increase the detection specificity for a particular ethnic.

Novel IRF6 Mutations Detected in Orofacial Cleft Patients by Targeted Massively Parallel Sequencing.

Common variants in interferon regulatory factor 6 ( IRF6) have been associated with nonsyndromic cleft lip with or without cleft palate (NSCL/P) as well as with tooth agenesis (TA). These variants contribute a small risk towards the 2 congenital conditions and explain only a small percentage of heritability. On the other hand, many IRF6 mutations are known to be a monogenic cause of disease for syndromic orofacial clefting (OFC). We hypothesize that IRF6 mutations in some rare instances could also cause nonsyndromic OFC. To find novel rare variants in IRF6 responsible for nonsyndromic OFC and TA, we performed targeted multiplex sequencing using molecular inversion probes (MIPs) in 1,072 OFC patients, 67 TA patients, and 706 controls. We identified 3 potentially pathogenic de novo mutations in OFC patients. In addition, 3 rare missense variants were identified, for which pathogenicity could not unequivocally be shown, as all variants were either inherited from an unaffected parent or the parental DNA was not available. Retrospective investigation of the patients with these variants revealed the presence of lip pits in one of the patients with a de novo mutation suggesting a Van der Woude syndrome (VWS) phenotype, whereas, in other patients, no lip pits were identified.

Posterior amorphous corneal dystrophy caused by a de novo deletion.

We present a newborn diagnosed with posterior amorphous corneal dystrophy (PACD). PACD is a rare disorder with partial or complete posterior lamellar corneal opacification. Genetic screening showed a deletion of chromosome 12q21.33-q22 containing the identified four small leucine-rich proteoglycans (SLRP's) associated with this particular dystrophy. Neither parents were carrier of the deletion. To our knowledge, this is the first report of a de novo mutation causing PACD.

Clinical implementation of NIPT - technical and biological challenges.

Non-invasive prenatal testing (NIPT) for fetal aneuploidy detection is increasingly being offered in the clinical setting. Whereas the majority of tests only report fetal trisomies 21, 18 and 13, genome-wide analyses have the potential to detect other fetal, as well as maternal, aneuploidies. In this review, we discuss the technical and clinical advantages and challenges associated with genome-wide cell-free fetal DNA profiling.

Review: Facial endophenotypes in non-syndromic orofacial clefting.

Cleft lip and/or palate (CL/P) is one of the most frequent congenital malformations, with a frequency of 1 in 700 live births. Non-syndromic orofacial clefting is a multifactorial condition, with both a genetic and an environmental component. Although numerous studies have been published addressing the genetic etiology of CL/P, this factor remains incompletely understood. A promising approach to find candidate gene regions for CL/P is the investigation of endophenotypes, which are characteristics associated with a certain condition and that can be an expression of underlying susceptibility genes. This review focuses on the known facial endophenotypes in CL/P (such as distortion of the orbicularis oris muscle and facial features in non-affected relatives of patients with CL/P) and genes that could be associated with these characteristics. Possibilities for further endophenotype-related studies in the field of non-syndromic CL/P are discussed.

Facial Characteristics and Olfactory Dysfunction: Two Endophenotypes Related to Nonsyndromic Cleft Lip and/or Palate.

Evidence exists for the presence of a specific facial phenotype in nonaffected first-degree relatives of persons with CL/P. An increased risk for olfactory dysfunction has also been reported in CL/P-relatives. These phenotypic features can probably be explained via the presence of CL/P-related susceptibility genes. We aimed at confirming the occurrence of these endophenotypic traits in first-degree CL/P-relatives, and we investigated the link between the facial phenotype and the smell capacity in this group. We studied the facial morphology of 88 nonaffected first-degree relatives of patients with CL/P and 33 control subjects without family history of facial clefting by 3D surface imaging and a spatially dense analysis of the images. Smell testing was performed in 30 relatives and compared with 23 control subjects. Nonaffected relatives showed midface retrusion, hypertelorism, and olfactory dysfunction, compared to controls. In addition, we show for the first time that olfactory dysfunction in relatives is correlated to a smaller upper nasal region. This might be explained by a smaller central olfactory system. The different facial morphology in the relatives with olfactory impairment as compared to the total group may be an illustration of the contribution of different genetic backgrounds to the occurrence of CL/P via different biological pathways.

Pierre Robin sequence: Management of respiratory and feeding complications during the first year of life in a tertiary referral centre.

OBJECTIVES: To review early clinical manifestations of Pierre Robin sequence (PRS) and their management during the first year of life in the University Hospitals Leuven. METHODS: Retrospective series of 48 patients with PRS born between 2001 and 2011 and treated at a tertiary referral hospital. Review of the current literature about management of respiratory and breathing difficulties in the early life of PRS patients. RESULTS: Of our cleft palate patients 15.3% presented with PRS. A syndrome was diagnosed in 14.6%, associated anomalies without a syndromic diagnosis in 56.3% and isolated PRS in 29.2% of the cases. Mortality rate directly related to PRS was 2.1%. Respiratory difficulties were observed in 83.3% and feeding difficulties in 95.6% of the patients. Respiratory problems were addressed in a conservative way in 75%, in a non-surgical invasive way in 42.5% and in a surgical way in 12.5%. A statistically significant relationship between the association of a syndrome or other anomalies, and a higher need for resuscitation and invasive treatment were found (chi-square test, p-values=0.019 and 0.034). Feeding difficulties were managed conservatively in 91.3%, invasively in 80.4% and surgically in 15.2%. CONCLUSIONS: PRS is frequently associated with other abnormalities or syndromes. Therefore routine screening for associated anomalies in neonates with PRS is recommendable. Respiratory and feeding complications are highly frequent and possibly severe, particularly in patients with associated anomalies or syndromes, and should be recognized and addressed appropriately in an early stage. There is a potential role for the nasopharyngeal airway in reducing the need for the more traditional surgical interventions for respiratory problems.

Short Stature in KBG Syndrome: First Responses to Growth Hormone Treatment.

BACKGROUND: KBG syndrome is a rare disorder characterized by intellectual disability and associated with macrodontia of the upper central incisors, specific craniofacial findings, short stature and skeletal anomalies. Genetic corroboration of a clinical diagnosis has been possible since 2011, upon identification of heterozygous mutations in or a deletion of the ANKRD11 gene. METHODS: We summarized the height data of 14 adults and 18 children (age range 2-16 years) with a genetically confirmed diagnosis of KBG syndrome. Two of these children were treated with growth hormones. RESULTS: Stature below the 3rd centile or -1.88 standard deviation score (SDS) was observed in 72% of KBG children and in 57% of KBG adults. Height below -2.50 SDS was observed in 62% of KBG children and in 36% of KBG adults. The mean SDS of height in KBG children was -2.56 and in KBG adults -2.17. Two KBG children on growth hormone therapy increased their height by 0.6 and 1 SDS within 1 year, respectively. The former also received a gonadotropin-releasing hormone agonist due to medical necessity. CONCLUSION: Short stature is prevalent in KBG syndrome, and spontaneous catch-up growth beyond childhood appears limited. Growth hormone intervention in short KBG children is perceived as promising.

Unilateral giant cell lesion of the jaw in Noonan syndrome.

Noonan syndrome (NS) is an etiologically heterogeneous disorder caused by mutations in the RAS-MAPK signaling pathway. Noonan-Like/Multiple Giant Cell Lesion (NL/MGCL) syndrome is initially described as the occurrence of multiple gnathic giant cell lesions in patients with phenotypic features of NS. Nowadays, NS/MGCL syndrome is considered a variant of the NS spectrum rather than a distinct entity. We report the case of a 14-year-old female patient carrying a SOS1 mutation with a unilateral giant cell lesion of the right mandible. Cross-sectional imaging such as CT and MRI are not specific for the diagnosis of oral giant cell lesions. Nonetheless, intralesional scattered foci of low SI on T2-WI, corresponding to hemosiderin deposits due to hemorrhage, can help the radiologist in narrowing down the differential diagnosis of gnathic lesions in patients with NS.

Exome sequencing identifies a recessive PIGN splice site mutation as a cause of syndromic congenital diaphragmatic hernia.

Using exome sequencing we identify a homozygous splice site mutation in the PIGN gene in a foetus with multiple congenital anomalies including bilateral diaphragmatic hernia, cardiovascular anomalies, segmental renal dysplasia, facial dysmorphism, cleft palate, and oligodactyly. This finding expands the phenotypic spectrum associated with homozygous loss of function mutations in PIGN, and adds further support for defective GPI anchor biosynthesis as a cause of developmental abnormalities. We demonstrate that exome sequencing is a valuable approach for the identification of a genetic cause in sporadic cases of multiple congenital anomalies (MCA) due to inherited mutations.

The communication of secondary variants: interviews with parents whose children have undergone array-CGH testing.

Children with unexplained developmental disabilities or congenital anomalies are increasingly being referred for genetic diagnostic testing using array-comparative genomic hybridisation (array-CGH) and next-generation sequencing (NGS) technologies. Their parents will have to deal with the secondary variants that will inevitably arise. We conducted 16 prospective semi-structured interviews with native Dutch-speaking parents whose children had undergone clinical array-CGH testing. The interviews explored the parents' experiences, expectations and opinions, specifically regarding the communication of results. Concrete examples of 'unexpected results' were provided to help guide the discussion, differing in severity, treatability, time of onset, level of risk, and carrier status. Data was analysed using content and narrative analysis methodologies. Parental motivations for and against the disclosure of unexpected results cluster around four main themes: actionability; knowledge; context; and characteristics of the result. Most parents wished to know all types of results. Disclosure was framed within a holistic, contextual, family-wide view. Genetic counselling should aim to integrate explorations of the motivations of parents surrounding the disclosure of results with good clinical care.

Identification of dosage-sensitive genes in fetuses referred with severe isolated congenital diaphragmatic hernia.

OBJECTIVE: Congenital diaphragmatic hernia (CDH) is a fetal abnormality affecting diaphragm and lung development with a high mortality rate despite advances in fetal and neonatal therapy. CDH may occur either as an isolated defect or in syndromic form for which the prognosis is worse. Although conventional karyotyping and, more recently, chromosomal microarrays support a substantial role for genetic factors, causal genes responsible for isolated CDH remain elusive. We propose that chromosomal microarray analysis will identify copy number variations (CNVs) associated with isolated CDH. METHODS: We perform a prospective genome-wide screen for CNVs using chromosomal microarrays on 75 fetuses referred with apparently isolated CDH, six of which were later reclassified as non-isolated CDH. RESULTS: The results pinpoint haploinsufficiency of NR2F2 as a cause of CDH and cardiovascular malformations. In addition, the 15q25.2 and 16p11.2 recurrent microdeletions are associated with isolated CDH. By using gene prioritisation and network analysis, we provide strong evidence for several novel dosage-sensitive candidate genes associated with CDH. CONCLUSIONS: Chromosomal microarray analysis detects submicroscopic CNVs associated with isolated CDH or CDH with cardiovascular malformations.

Aetiology of congenital hearing loss: a cohort review of 569 subjects.

OBJECTIVE: Newborn hearing screening was implemented in Flanders about fifteen years ago. The aim of this study was to determine the aetiology of hearing loss detected by the Flemish screening programme. METHODS: From 1997 to 2011, 569 neonates were referred to our tertiary referral centre after failed neonatal screening with Auditory Brainstem Responses. In case hearing loss (HL) was confirmed, further diagnostic testing was launched. A retrospective chart review was performed analysing the degree of HL, risk factor and aetiology. RESULTS: Metabolic disorders (0.5%), infectious diseases (35.8%), congenital malformations (6.1%) and genetic abnormalities (19.8%), whether or not syndromic, were retained. In 35% of the subjects no obvious aetiology could be determined in the current study. CONCLUSION: In contrast to the literature findings, this series shows a genetic syndromic cause in 80% of the genetic bilateral HL cases. On the other hand connexin positive diagnoses were mostly underrepresented in this study, showing the need for better screening.

Spectrum of temporal bone abnormalities in patients with Waardenburg syndrome and SOX10 mutations.

BACKGROUND AND PURPOSE: Waardenburg syndrome, characterized by deafness and pigmentation abnormalities, is clinically and genetically heterogeneous, consisting of 4 distinct subtypes and involving several genes. SOX10 mutations have been found both in types 2 and 4 Waardenburg syndrome and neurologic variants. The purpose of this study was to evaluate both the full spectrum and relative frequencies of inner ear malformations in these patients. MATERIALS AND METHODS: Fifteen patients with Waardenburg syndrome and different SOX10 mutations were studied retrospectively. Imaging was performed between February 2000 and March 2010 for cochlear implant work-up, diagnosis of hearing loss, and/or evaluation of neurologic impairment. Eleven patients had both CT and MR imaging examinations, 3 had MR imaging only, and 1 had CT only. RESULTS: Temporal bone abnormalities were bilateral. The most frequent pattern associated agenesis or hypoplasia of ≥1 semicircular canal, an enlarged vestibule, and a cochlea with a reduced size and occasionally an abnormal shape, but with normal partition in the 13/15 cases that could be analyzed. Three patients lacked a cochlear nerve, bilaterally in 2 patients. In addition, associated abnormalities were found when adequate MR imaging sequences were available: agenesis of the olfactory bulbs (7/8), hypoplastic or absent lacrimal glands (11/14), hypoplastic parotid glands (12/14), and white matter signal anomalies (7/13). CONCLUSIONS: In the appropriate clinical context, bilateral agenesis or hypoplasia of the semicircular canals or both, associated with an enlarged vestibule and a cochlear deformity, strongly suggests a diagnosis of Waardenburg syndrome linked to a SOX10 mutation.

Microduplication 22q11.2: a description of the clinical, developmental and behavioral characteristics during childhood.

Microduplication 22q11.2 is a recently discovered genomic disorder. So far, targeted research on the cognitive and behavioral characteristics of individuals with this microduplication is limited. Therefore, 11 Flemish children (3-13 years old) with a microduplication 22q 1.2 were investigated in order to describe their clinical, developmental and behavioral characteristics. We measured their general intelligence, visual-motor capacities, attention, behavioral problems and characteristics of autism. In addition, there was an interview with the parents on developmental history and we reviewed available information from other specialists. The results show that the cognitive and behavioral phenotype of the children with microduplication 22q.11.2 is very wide and heterogeneous. Some of the children have a cognitively nearly normal development whereas others are more severely affected. All children had some degree of developmental delay and some of them have an intellectual disability. The most common clinical features include congenital malformations such as heart defects and cleft lip, feeding problems, hearing impairment and facial dysmorphism. The most common non-medical problems are learning difficulties, motor impairment, attention deficits, social problems and behavioral problems. There is no correlation between the size of the duplication and the phenotype.

Neuropsychopathology in 7 Patients with the 22q13 Deletion Syndrome: Presence of Bipolar Disorder and Progressive Loss of Skills.

The 22q13 deletion syndrome is characterised by intellectual disability (ID), delayed or absent speech, autistic-like behaviour and minor, nonspecific dysmorphic features. The deletion of the SHANK3 gene is thought to be responsible for these features. In this study, the clinical data of 7 patients with the 22q13 deletion syndrome are presented, obtained by clinical genetic examination, direct behavioural observation and by interview of family members and/or caregivers, complemented by behavioural questionnaires. The specific focus was on behaviour, psychopathology and the level of functioning during life course in order to determine common features that might contribute to the delineation of the syndrome. Major findings were a high incidence of psychiatric disorders, more in particular bipolar disorder (BPD) and attention deficit hyperactivity disorder (ADHD), and a sudden deterioration after acute events, in addition to a progressive loss of skills over years. Therefore, a deletion of SHANK3 may result in a dysfunctional nervous system, more susceptible to developmental problems and psychiatric disorders on the one hand, less able to recuperate after psychiatric and somatic events, and more vulnerable to degeneration at long term on the other hand. These results are exploratory and need to be confirmed in a larger sample.