Epigenotype-genotype-phenotype correlations in SETD1A and SETD2 chromatin disorders.

Germline pathogenic variants in two genes encoding the lysine-specific histone methyltransferase genes SETD1A and SETD2 are associated with neurodevelopmental disorders (NDDs) characterized by developmental delay and congenital anomalies. The SETD1A and SETD2 gene products play a critical role in chromatin-mediated regulation of gene expression. Specific methylation episignatures have been detected for a range of chromatin gene-related NDDs and have impacted clinical practice by improving the interpretation of variant pathogenicity. To investigate if SETD1A and/or SETD2-related NDDs are associated with a detectable episignature, we undertook targeted genome-wide methylation profiling of > 2 M CpGs using a next-generation sequencing-based assay. A comparison of methylation profiles in patients with SETD1A variants (n = 6) did not reveal evidence of a strong methylation episignature. A review of the clinical and genetic features of the SETD2 patient group revealed that, as reported previously, there were phenotypic differences between patients with truncating mutations (n = 4, Luscan-Lumish syndrome; MIM:616831) and those with missense codon 1740 variants [p.Arg1740Trp (n = 4) and p.Arg1740Gln (n = 2)]. Both SETD2 subgroups demonstrated a methylation episignature, which was characterized by hypomethylation and hypermethylation events, respectively. Within the codon 1740 subgroup, both the methylation changes and clinical phenotype were more severe in those with p.Arg1740Trp variants. We also noted that two of 10 cases with a SETD2-NDD had developed a neoplasm. These findings reveal novel epigenotype-genotype-phenotype correlations in SETD2-NDDs and predict a gain-of-function mechanism for SETD2 codon 1740 pathogenic variants.

Identification and functional evaluation of GRIA1 missense and truncation variants in individuals with ID: An emerging neurodevelopmental syndrome.

GRIA1 encodes the GluA1 subunit of α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors, which are ligand-gated ion channels that act as excitatory receptors for the neurotransmitter L-glutamate (Glu). AMPA receptors (AMPARs) are homo- or heteromeric protein complexes with four subunits, each encoded by different genes, GRIA1 to GRIA4. Although GluA1-containing AMPARs have a crucial role in brain function, the human phenotype associated with deleterious GRIA1 sequence variants has not been established. Subjects with de novo missense and nonsense GRIA1 variants were identified through international collaboration. Detailed phenotypic and genetic assessments of the subjects were carried out and the pathogenicity of the variants was evaluated in vitro to characterize changes in AMPAR function and expression. In addition, two Xenopus gria1 CRISPR-Cas9 F0 models were established to characterize the in vivo consequences. Seven unrelated individuals with rare GRIA1 variants were identified. One individual carried a homozygous nonsense variant (p.Arg377Ter), and six had heterozygous missense variations (p.Arg345Gln, p.Ala636Thr, p.Ile627Thr, and p.Gly745Asp), of which the p.Ala636Thr variant was recurrent in three individuals. The cohort revealed subjects to have a recurrent neurodevelopmental disorder mostly affecting cognition and speech. Functional evaluation of major GluA1-containing AMPAR subtypes carrying the GRIA1 variant mutations showed that three of the four missense variants profoundly perturb receptor function. The homozygous stop-gain variant completely destroys the expression of GluA1-containing AMPARs. The Xenopus gria1 models show transient motor deficits, an intermittent seizure phenotype, and a significant impairment to working memory in mutants. These data support a developmental disorder caused by both heterozygous and homozygous variants in GRIA1 affecting AMPAR function.

De novo missense variants in FBXO11 alter its protein expression and subcellular localization.

Recently, others and we identified de novo FBXO11 (F-Box only protein 11) variants as causative for a variable neurodevelopmental disorder (NDD). We now assembled clinical and mutational information on 23 additional individuals. The phenotypic spectrum remains highly variable, with developmental delay and/or intellectual disability as the core feature and behavioral anomalies, hypotonia and various facial dysmorphism as frequent aspects. The mutational spectrum includes intragenic deletions, likely gene disrupting and missense variants distributed across the protein. To further characterize the functional consequences of FBXO11 missense variants, we analyzed their effects on protein expression and localization by overexpression of 17 different mutant constructs in HEK293 and HeLa cells. We found that the majority of missense variants resulted in subcellular mislocalization and/or reduced FBXO11 protein expression levels. For instance, variants located in the nuclear localization signal and the N-terminal F-Box domain lead to altered subcellular localization with exclusion from the nucleus or the formation of cytoplasmic aggregates and to reduced protein levels in western blot. In contrast, variants localized in the C-terminal Zn-finger UBR domain lead to an accumulation in the cytoplasm without alteration of protein levels. Together with the mutational data, our functional results suggest that most missense variants likely lead to a loss of the original FBXO11 function and thereby highlight haploinsufficiency as the most likely disease mechanism for FBXO11-associated NDDs.

RLIM Is a Candidate Dosage-Sensitive Gene for Individuals with Varying Duplications of Xq13, Intellectual Disability, and Distinct Facial Features.

Interpretation of the significance of maternally inherited X chromosome variants in males with neurocognitive phenotypes continues to present a challenge to clinical geneticists and diagnostic laboratories. Here we report 14 males from 9 families with duplications at the Xq13.2-q13.3 locus with a common facial phenotype, intellectual disability (ID), distinctive behavioral features, and a seizure disorder in two cases. All tested carrier mothers had normal intelligence. The duplication arose de novo in three mothers where grandparental testing was possible. In one family the duplication segregated with ID across three generations. RLIM is the only gene common to our duplications. However, flanking genes duplicated in some but not all the affected individuals included the brain-expressed genes NEXMIF, SLC16A2, and the long non-coding RNA gene FTX. The contribution of the RLIM-flanking genes to the phenotypes of individuals with different size duplications has not been fully resolved. Missense variants in RLIM have recently been identified to cause X-linked ID in males, with heterozygous females typically having normal intelligence and highly skewed X chromosome inactivation. We detected consistent and significant increase of RLIM mRNA and protein levels in cells derived from seven affected males from five families with the duplication. Subsequent analysis of MDM2, one of the targets of the RLIM E3 ligase activity, showed consistent downregulation in cells from the affected males. All the carrier mothers displayed normal RLIM mRNA levels and had highly skewed X chromosome inactivation. We propose that duplications at Xq13.2-13.3 including RLIM cause a recognizable but mild neurocognitive phenotype in hemizygous males.

De Novo SOX6 Variants Cause a Neurodevelopmental Syndrome Associated with ADHD, Craniosynostosis, and Osteochondromas.

SOX6 belongs to a family of 20 SRY-related HMG-box-containing (SOX) genes that encode transcription factors controlling cell fate and differentiation in many developmental and adult processes. For SOX6, these processes include, but are not limited to, neurogenesis and skeletogenesis. Variants in half of the SOX genes have been shown to cause severe developmental and adult syndromes, referred to as SOXopathies. We here provide evidence that SOX6 variants also cause a SOXopathy. Using clinical and genetic data, we identify 19 individuals harboring various types of SOX6 alterations and exhibiting developmental delay and/or intellectual disability; the individuals are from 17 unrelated families. Additional, inconstant features include attention-deficit/hyperactivity disorder (ADHD), autism, mild facial dysmorphism, craniosynostosis, and multiple osteochondromas. All variants are heterozygous. Fourteen are de novo, one is inherited from a mosaic father, and four offspring from two families have a paternally inherited variant. Intragenic microdeletions, balanced structural rearrangements, frameshifts, and nonsense variants are predicted to inactivate the SOX6 variant allele. Four missense variants occur in residues and protein regions highly conserved evolutionarily. These variants are not detected in the gnomAD control cohort, and the amino acid substitutions are predicted to be damaging. Two of these variants are located in the HMG domain and abolish SOX6 transcriptional activity in vitro. No clear genotype-phenotype correlations are found. Taken together, these findings concur that SOX6 haploinsufficiency leads to a neurodevelopmental SOXopathy that often includes ADHD and abnormal skeletal and other features.

De Novo Missense Substitutions in the Gene Encoding CDK8, a Regulator of the Mediator Complex, Cause a Syndromic Developmental Disorder.

The Mediator is an evolutionarily conserved, multi-subunit complex that regulates multiple steps of transcription. Mediator activity is regulated by the reversible association of a four-subunit module comprising CDK8 or CDK19 kinases, together with cyclin C, MED12 or MED12L, and MED13 or MED13L. Mutations in MED12, MED13, and MED13L were previously identified in syndromic developmental disorders with overlapping phenotypes. Here, we report CDK8 mutations (located at 13q12.13) that cause a phenotypically related disorder. Using whole-exome or whole-genome sequencing, and by international collaboration, we identified eight different heterozygous missense CDK8 substitutions, including 10 shown to have arisen de novo, in 12 unrelated subjects; a recurrent mutation, c.185C>T (p.Ser62Leu), was present in five individuals. All predicted substitutions localize to the ATP-binding pocket of the kinase domain. Affected individuals have overlapping phenotypes characterized by hypotonia, mild to moderate intellectual disability, behavioral disorders, and variable facial dysmorphism. Congenital heart disease occurred in six subjects; additional features present in multiple individuals included agenesis of the corpus callosum, ano-rectal malformations, seizures, and hearing or visual impairments. To evaluate the functional impact of the mutations, we measured phosphorylation at STAT1-Ser727, a known CDK8 substrate, in a CDK8 and CDK19 CRISPR double-knockout cell line transfected with wild-type (WT) or mutant CDK8 constructs. These experiments demonstrated a reduction in STAT1 phosphorylation by all mutants, in most cases to a similar extent as in a kinase-dead control. We conclude that missense mutations in CDK8 cause a developmental disorder that has phenotypic similarity to syndromes associated with mutations in other subunits of the Mediator kinase module, indicating probable overlap in pathogenic mechanisms.

Further delineation of phenotypic spectrum of SCN2A-related disorder.

SCN2A-related disorders include intellectual disability, autism spectrum disorder, seizures, episodic ataxia, and schizophrenia. In this study, the phenotype-genotype association in SCN2A-related disorders was further delineated by collecting detailed clinical and molecular characteristics. Using previously proposed genotype-phenotype hypotheses based on variant function and position, the potential of phenotype prediction from the variants found was examined. Patients were identified through the Deciphering Developmental Disorders study and gene matching strategies. Phenotypic information and variant interpretation evidence were collated. Seventeen previously unreported patients and five patients who had been previously reported (but with minimal phenotypic and segregation data) were included (10 males, 12 females; median age 10.5 years). All patients had developmental delays and the majority had intellectual disabilities. Seizures were reported in 15 of 22 (68.2%), four of 22 (18.2%) had autism spectrum disorder and no patients were reported with episodic ataxia. The majority of variants were de novo. One family had presumed gonadal mosaicism. The correlation of the use of sodium channel-blocking antiepileptic drugs with phenotype or genotype was variable. These data suggest that variant type and position alone can provide some predictive information about the phenotype in a proportion of cases, but more precise assessment of variant function is needed for meaningful phenotype prediction.

Antenatal counselling for prospective parents whose fetus has a neurological anomaly: part 1, experiences and recommendations for service design.

Prospective parents whose fetus is diagnosed with a neurological anomaly go through a complex range of emotions. They describe their discussions of antenatal counselling from health care professionals as focusing too much on the nature of the anomaly involving unintelligible medical terminology, when what they really want is a picture of the best- and worst-case scenarios. Whilst information on the level of risk for their fetus is important, it is not the parents' primary concern. When statistics for risk are given, they may not be as well understood as the health care professionals think. This review discusses the published evidence on antenatal counselling and recommendations for explaining risk to parents of fetuses with neurological anomalies. From this data we make recommendations for the organization of antenatal counselling services.

Antenatal counselling for prospective parents whose fetus has a neurological anomaly: part 2, risks of adverse outcome in common anomalies.

After diagnosis of a fetal neurological anomaly, prospective parents want to know the best and worst-case scenarios and an estimation of the risk to their infant of having an atypical developmental outcome. The literature on developmental outcomes for fetal neurological anomalies is poor: studies are characterized by retrospective design, small sample size, often no standardized assessment of development, and differing definitions of anomalies. This review provides an aide-memoir on the risks of adverse neurodevelopmental outcome for ventriculomegaly, cortical anomalies, microcephaly, macrocephaly, agenesis of the corpus callosum, posterior fossa anomalies, and myelomeningocele, to assist healthcare professionals in counselling. The data in this review should be used alongside recommendations on counselling and service design described in part 1 to provide antenatal counselling.

Genotype-phenotype correlation at codon 1740 of SETD2.

The SET domain containing 2, histone lysine methyltransferase encoded by SETD2 is a dual-function methyltransferase for histones and microtubules and plays an important role for transcriptional regulation, genomic stability, and cytoskeletal functions. Specifically, SETD2 is associated with trimethylation of histone H3 at lysine 36 (H3K36me3) and methylation of α-tubulin at lysine 40. Heterozygous loss of function and missense variants have previously been described with Luscan-Lumish syndrome (LLS), which is characterized by overgrowth, neurodevelopmental features, and absence of overt congenital anomalies. We have identified 15 individuals with de novo variants in codon 1740 of SETD2 whose features differ from those with LLS. Group 1 consists of 12 individuals with heterozygous variant c.5218C>T p.(Arg1740Trp) and Group 2 consists of 3 individuals with heterozygous variant c.5219G>A p.(Arg1740Gln). The phenotype of Group 1 includes microcephaly, profound intellectual disability, congenital anomalies affecting several organ systems, and similar facial features. Individuals in Group 2 had moderate to severe intellectual disability, low normal head circumference, and absence of additional major congenital anomalies. While LLS is likely due to loss of function of SETD2, the clinical features seen in individuals with variants affecting codon 1740 are more severe suggesting an alternative mechanism, such as gain of function, effects on epigenetic regulation, or posttranslational modification of the cytoskeleton. Our report is a prime example of different mutations in the same gene causing diverging phenotypes and the features observed in Group 1 suggest a new clinically recognizable syndrome uniquely associated with the heterozygous variant c.5218C>T p.(Arg1740Trp) in SETD2.

Diagnosis of pyridoxine-dependent epilepsy in an adult presenting with recurrent status epilepticus.

Pyridoxine-dependent epilepsy (PDE) is a genetic metabolic disease caused by inborn errors affecting vitamin B6 metabolism, which typically presents with neonatal seizures resistant to antiepileptic drugs (AEDs). Treatment with pyridoxine terminates seizures and prevents neurological decline. We describe a case in which the diagnosis was established at the age of 22 years. Birth and development were normal, but there was a history of three isolated tonic-clonic seizures during childhood and adolescence. At the age of 18 years, she developed frequent focal motor seizures, many evolving into tonic-clonic seizures. Electroencephalography identified a focus in the posterior right hemisphere, but magnetic resonance imaging of the brain was normal. Over the next 3 years, she was hospitalized with uncontrolled seizures on six occasions and spent a total of 121 days in intensive care. The seizures proved resistant to 12 different AEDs. Exome sequencing revealed two pathogenic mutations in ALDH7A1. Since starting on pyridoxine 50 mg once daily, she has been seizure-free, all AEDs have been withdrawn, and cognition has improved to premorbid levels. This case illustrates the importance of considering PDE in drug-resistant epilepsy in adults.

PAPSS2-related brachyolmia: Clinical and radiological phenotype in 18 new cases.

Brachyolmia is a skeletal dysplasia characterized by short spine-short stature, platyspondyly, and minor long bone abnormalities. We describe 18 patients, from different ethnic backgrounds and ages ranging from infancy to 19 years, with the autosomal recessive form, associated with PAPSS2. The main clinical features include disproportionate short stature with short spine associated with variable symptoms of pain, stiffness, and spinal deformity. Eight patients presented prenatally with short femora, whereas later in childhood their short-spine phenotype emerged. We observed the same pattern of changing skeletal proportion in other patients. The radiological findings included platyspondyly, irregular end plates of the elongated vertebral bodies, narrow disc spaces and short over-faced pedicles. In the limbs, there was mild shortening of femoral necks and tibiae in some patients, whereas others had minor epiphyseal or metaphyseal changes. In all patients, exome and Sanger sequencing identified homozygous or compound heterozygous PAPSS2 variants, including c.809G>A, common to white European patients. Bi-parental inheritance was established where possible. Low serum DHEAS, but not overt androgen excess was identified. Our study indicates that autosomal recessive brachyolmia occurs across continents and may be under-recognized in infancy. This condition should be considered in the differential diagnosis of short femora presenting in the second trimester.

Heterozygous mutations affecting the protein kinase domain of CDK13 cause a syndromic form of developmental delay and intellectual disability.

INTRODUCTION: Recent evidence has emerged linking mutations in CDK13 to syndromic congenital heart disease. We present here genetic and phenotypic data pertaining to 16 individuals with CDK13 mutations. METHODS: Patients were investigated by exome sequencing, having presented with developmental delay and additional features suggestive of a syndromic cause. RESULTS: Our cohort comprised 16 individuals aged 4-16 years. All had developmental delay, including six with autism spectrum disorder. Common findings included feeding difficulties (15/16), structural cardiac anomalies (9/16), seizures (4/16) and abnormalities of the corpus callosum (4/11 patients who had undergone MRI). All had craniofacial dysmorphism, with common features including short, upslanting palpebral fissures, hypertelorism or telecanthus, medial epicanthic folds, low-set, posteriorly rotated ears and a small mouth with thin upper lip vermilion. Fifteen patients had predicted missense mutations, including five identical p.(Asn842Ser) substitutions and two p.(Gly717Arg) substitutions. One patient had a canonical splice acceptor site variant (c.2898-1G>A). All mutations were located within the protein kinase domain of CDK13. The affected amino acids are highly conserved, and in silico analyses including comparative protein modelling predict that they will interfere with protein function. The location of the missense mutations in a key catalytic domain suggests that they are likely to cause loss of catalytic activity but retention of cyclin K binding, resulting in a dominant negative mode of action. Although the splice-site mutation was predicted to produce a stable internally deleted protein, this was not supported by expression studies in lymphoblastoid cells. A loss of function contribution to the underlying pathological mechanism therefore cannot be excluded, and the clinical significance of this variant remains uncertain. CONCLUSIONS: These patients demonstrate that heterozygous, likely dominant negative mutations affecting the protein kinase domain of the CDK13 gene result in a recognisable, syndromic form of intellectual disability, with or without congenital heart disease.

Differential regulation of two FLNA transcripts explains some of the phenotypic heterogeneity in the loss-of-function filaminopathies.

Loss-of-function mutations in the X-linked gene FLNA can lead to abnormal neuronal migration, vascular and cardiac defects, and congenital intestinal pseudo-obstruction (CIPO), the latter characterized by anomalous intestinal smooth muscle layering. Survival in male hemizygotes for such mutations is dependent on retention of residual FLNA function but it is unclear why a subgroup of males with mutations in the 5' end of the gene can present with CIPO alone. Here, we demonstrate evidence for the presence of two FLNA isoforms differing by 28 residues at the N-terminus initiated at ATG+1 and ATG+82 . A male with CIPO (c.18_19del) exclusively expressed FLNA ATG+82 , implicating the longer protein isoform (ATG+1 ) in smooth muscle development. In contrast, mutations leading to reduction of both isoforms are associated with compound phenotypes affecting the brain, heart, and intestine. RNA-seq data revealed three distinct transcription start sites, two of which produce a protein isoform utilizing ATG+1 while the third utilizes ATG+82 . Transcripts sponsoring translational initiation at ATG+1 predominate in intestinal smooth muscle, and are more abundant compared with the level measured in fibroblasts. Together these observations describe a new mechanism of tissue-specific regulation of FLNA that could reflect the differing mechanical requirements of these cell types during development.

De novo mutations in NALCN cause a syndrome characterized by congenital contractures of the limbs and face, hypotonia, and developmental delay.

Freeman-Sheldon syndrome, or distal arthrogryposis type 2A (DA2A), is an autosomal-dominant condition caused by mutations in MYH3 and characterized by multiple congenital contractures of the face and limbs and normal cognitive development. We identified a subset of five individuals who had been putatively diagnosed with "DA2A with severe neurological abnormalities" and for whom congenital contractures of the limbs and face, hypotonia, and global developmental delay had resulted in early death in three cases; this is a unique condition that we now refer to as CLIFAHDD syndrome. Exome sequencing identified missense mutations in the sodium leak channel, non-selective (NALCN) in four families affected by CLIFAHDD syndrome. We used molecular-inversion probes to screen for NALCN in a cohort of 202 distal arthrogryposis (DA)-affected individuals as well as concurrent exome sequencing of six other DA-affected individuals, thus revealing NALCN mutations in ten additional families with "atypical" forms of DA. All 14 mutations were missense variants predicted to alter amino acid residues in or near the S5 and S6 pore-forming segments of NALCN, highlighting the functional importance of these segments. In vitro functional studies demonstrated that NALCN alterations nearly abolished the expression of wild-type NALCN, suggesting that alterations that cause CLIFAHDD syndrome have a dominant-negative effect. In contrast, homozygosity for mutations in other regions of NALCN has been reported in three families affected by an autosomal-recessive condition characterized mainly by hypotonia and severe intellectual disability. Accordingly, mutations in NALCN can cause either a recessive or dominant condition characterized by varied though overlapping phenotypic features, perhaps based on the type of mutation and affected protein domain(s).

ADCY5-related dyskinesia presenting as familial myoclonus-dystonia.

We describe a family with an autosomal dominant familial dyskinesia resembling myoclonus-dystonia associated with a novel missense mutation in ADCY5, found through whole-exome sequencing. A tiered analytical approach was used to analyse whole-exome sequencing data from an affected grandmother-granddaughter pair. Whole-exome sequencing identified 18,000 shared variants, of which 46 were non-synonymous changes not present in a local cohort of control exomes (n = 422). Further filtering based on predicted splicing effect, minor allele frequency in the 1000 Genomes Project and on phylogenetic conservation yielded 13 candidate variants, of which the heterozygous missense mutation c.3086T>G, p. M1029R in ADCY5 most closely matched the observed phenotype. This report illustrates the utility of whole-exome sequencing in cases of undiagnosed movement disorders with clear autosomal dominant inheritance. Moreover, ADCY5 mutations should be considered in cases with apparent myoclonus-dystonia, particularly where SCGE mutations have been excluded. ADCY5-related dyskinesia may manifest variable expressivity within a single family, and affected individuals may be initially diagnosed with differing neurological phenotypes.

Further defining the phenotypic spectrum of B4GALT7 mutations.

Proteoglycans are components of the extracellular matrix with diverse biological functions. Defects in proteoglycan synthesis have been linked to several human diseases with common features of short stature, hypermobility, joint dislocations, and skeletal dysplasia. B4GALT7 encodes galactosyltransferase-I that catalyzes the addition of a galactose moiety to a xylosyl group in the tetrasaccharide linker of proteoglycans. Mutations in this gene have been associated with the rare progeroid form of Ehlers Danlos syndrome and in addition more recently found to underlie Larsen of Reunion Island syndrome. Nine individuals have been reported with a diagnosis of the progeroid form of Ehlers Danlos syndrome, four of whom have had molecular characterization showing homozygous or compound heterozygous mutations in B4GALT7. We report two newly described patients with compound heterozygous mutations in B4GALT7, and show that the six individuals with confirmed mutations do not have the progeroid features described in the original five patients with a clinical diagnosis of the progeroid form of Ehlers Danlos syndrome. We suggest that galactosyltransferase-I deficiency does not cause the progeroid form of Ehlers Danlos syndrome, but instead results in a clinically recognizable syndrome comprising short stature, joint hypermobility, radioulnar synostosis, and severe hypermetropia. This group of syndromic patients are on a phenotypic spectrum with individuals who have Larsen of Reunion Island syndrome, although the key features of osteopenia, fractures and hypermetropia have not been reported in patients from Reunion Island. © 2016 Wiley Periodicals, Inc.

Clinical and genetic aspects of KBG syndrome.

KBG syndrome is characterized by short stature, distinctive facial features, and developmental/cognitive delay and is caused by mutations in ANKRD11, one of the ankyrin repeat-containing cofactors. We describe 32 KBG patients aged 2-47 years from 27 families ascertained via two pathways: targeted ANKRD11 sequencing (TS) in a group who had a clinical diagnosis of KBG and whole exome sequencing (ES) in a second group in whom the diagnosis was unknown. Speech delay and learning difficulties were almost universal and variable behavioral problems frequent. Macrodontia of permanent upper central incisors was seen in 85%. Other clinical features included short stature, conductive hearing loss, recurrent middle ear infection, palatal abnormalities, and feeding difficulties. We recognized a new feature of a wide anterior fontanelle with delayed closure in 22%. The subtle facial features of KBG syndrome were recognizable in half the patients. We identified 20 ANKRD11 mutations (18 novel: all truncating) confirmed by Sanger sequencing in 32 patients. Comparison of the two ascertainment groups demonstrated that facial/other typical features were more subtle in the ES group. There were no conclusive phenotype-genotype correlations. Our findings suggest that mutation of ANKRD11 is a common Mendelian cause of developmental delay. Affected patients may not show the characteristic KBG phenotype and the diagnosis is therefore easily missed. We propose updated diagnostic criteria/clinical recommendations for KBG syndrome and suggest that inclusion of ANKRD11 will increase the utility of gene panels designed to investigate developmental delay. © 2016 The Authors. American Journal of Medical Genetics Part A Published by Wiley Periodicals, Inc.

Clinical delineation of the PACS1-related syndrome--Report on 19 patients.

We report on 19 individuals with a recurrent de novo c.607C>T mutation in PACS1. This specific mutation gives rise to a recognizable intellectual disability syndrome. There is a distinctive facial appearance (19/19), characterized by full and arched eyebrows, hypertelorism with downslanting palpebral fissures, long eye lashes, ptosis, low set and simple ears, bulbous nasal tip, wide mouth with downturned corners and a thin upper lip with an unusual "wavy" profile, flat philtrum, and diastema of the teeth. Intellectual disability, ranging from mild to moderate, was present in all. Hypotonia is common in infancy (8/19). Seizures are frequent (12/19) and respond well to anticonvulsive medication. Structural malformations are common, including heart (10/19), brain (12/16), eye (10/19), kidney (3/19), and cryptorchidism (6/12 males). Feeding dysfunction is presenting in infancy with failure to thrive (5/19), gastroesophageal reflux (6/19), and gastrostomy tube placement (4/19). There is persistence of oral motor dysfunction. We provide suggestions for clinical work-up and management and hope that the present study will facilitate clinical recognition of further cases.

Two further patients with the 1q24 deletion syndrome expand the phenotype: A possible role for the miR199-214 cluster in the skeletal features of the condition.

Submicroscopic deletions within chromosome 1q24q25 are associated with a syndromic phenotype of short stature, brachydactyly, learning difficulties, and facial dysmorphism. The critical region for the deletion phenotype has previously been narrowed to a 1.9 Mb segment containing 13 genes. We describe two further patients with 1q24 microdeletions and the skeletal phenotype, the first of whom has normal intellect, whereas the second has only mild learning impairment. The deletion in the first patient is very small and further narrows the critical interval for the striking skeletal aspects of this condition to a region containing only Dynamin 3 (DNM3) and two microRNAs that are harbored within intron 14 of this gene: miR199 and miR214. Mouse studies raise the possibility that these microRNAs may be implicated in the short stature and skeletal abnormalities of this microdeletion condition. The deletion in the second patient spans the previously reported critical region and indicates that the cognitive impairment may not always be as severe as previous reports suggest.