Short Report: 10-year follow-up of a boy with ARID1B-related disorder. Early intervention, longitudinal dimensional phenotype, brain imaging and outcome.

ARID1B-related disorders constitute a clinical continuum, from classic Coffin-Siris syndrome to intellectual disability (ID) with or without nonspecific dysmorphic features. Here, we describe an 11-year-old boy with an ARID1B mutation whose phenotype changed from severe developmental delay and ID to a complex neurodevelopmental disorder with multidimensional impairments, including normal intelligence despite heterogeneous IQ scores, severe motor coordination disorder, oral language disorder and attention-deficit/hyperactivity disorder. Phenotypic changes occurred after early intensive remediation and paralleled the normalization of myelination impairments, as evidenced by early brain imaging. WHAT THIS PAPER ADDS?: This report describes a 10-year multidisciplinary follow-up of a child with an ARID1B mutation who received early intensive remediation and whose phenotype changed during development. Clinical improvement paralleled the normalization of myelination impairments. This case supports a dimensional approach for complex neurodevelopmental disorders.

[The use of magnetic therapy in the treatment of children with lower micrognathia using compression-distraction osteosynthesis]. / Primenenie magnitoterapii pri lechenii detei s nizhnei mikrognatiei metodom kompressionno-distraktsionnogo osteosinteza.

PURPOSE: To study the effect of magnetic therapy on the formation of distraction regenerate of the lower jaw in patients with lower micrognathia. MATERIALS AND METHODS: The study comprised 159 patients with inferior micrognathia of congenital and acquired etiology. The patients were divided into 2 groups. The main group consisted of 112 patients who received magnetic therapy: 55 patients with congenital micrognathia and 57 patients with acquired micrognathia. The control group included 47 patients who did not undergo magnetic therapy: 20 patients with congenital micrognathia and 27 patients with acquired micrognathia. Magnetic therapy was performed daily starting from day 1 or 2 after surgery. Ultrasound monitoring began on the 7th day of distraction and was carried out every 3-4 days, which made it possible to assess the dynamics of the formation of the distraction regenerate. RESULTS: Ultrasound examination on the 7th day of distraction revealed that in the main group the number of distraction regenerates of the normotrophic type was 36.5%, hypotrophic type 18%, hypertrophic type 54.5%. In the control group, the corresponding rates were 53%, 31% and 22%. CONCLUSION: Magnetic therapy induces osteogenesis and accelerates the maturation of the distraction regenerate. This makes it possible to accelerate the pace of distraction without reducing the quality of the regenerate.

Expanding the clinical spectrum of Coffin-Siris syndrome with anorectal malformations: Case report and review of the literature.

Anorectal malformations (ARMs) represent a wide spectrum of congenital anomalies of the anus and rectum, of which more than half are syndromic. Their etiology is highly heterogeneous and still poorly understood. We report a 4-year-old girl who initially presented with an isolated ARM, and subsequently developed a global developmental delay as part of an ARID1B-related Coffin-Siris syndrome (CSS). A co-occurrence of ARMs and CSS in an individual by chance is unexpected since both diseases are very rare. A review of the literature enabled us to identify 10 other individuals with both CSS and ARMs. Among the ten individuals reported in this study, 8 had a variant in ARID1A, 2 in ARID1B, and 1 in SMARCA4. This more frequent than expected association between CSS and ARM indicates that some ARMs are most likely part of the CSS spectrum, especially for ARID1A-related CSS.

DPF2-related Coffin-Siris syndrome type 7 in two generations.

To date 11 patients with Coffin-Siris syndrome type 7 (OMIM 618027) have been described since the first literature report. All reported patients carried de novo variants with presumed dominant negative effect, which localized in the PHD1/PHD2 domains of DPF2. Here we report on the first familial case of Coffin-Siris syndrome type 7. The index patient presented during the 1st year of life with failure to thrive and ectodermal anomalies. The genetic analysis using whole exome sequencing showed a likely pathogenic missense variant in the PHD1 region. The family analysis showed that the mother as well as the older brother of the index patient also carried the detected DPF2 variant in heterozygous state. The mother had a history of school difficulties but no history of failure to thrive and was overall mildly affected. The brother showed developmental delay with autistic features, ectodermal anomalies and overlapping morphologic features but did not have a history of growth failure problems. To our knowledge this is the first report of an inherited likely pathogenic variant in DPF2, underlining the variability of the associated phenotype as well as the importance of considering inherited DPF2 variants during the variant filtering strategy of whole exome data.

De novo variation in ARID1B gene causes Coffin-Siris syndrome 1 in a Chinese family with excessive early-onset high myopia.

Coffin-Siris syndrome (CSS) is a rare autosomal dominant inheritance disorder characterized by distinctive facial features, hypoplasia of the distal phalanx or nail of the fifth and additional digits, developmental or cognitive delay of varying degree, hypotonia, hirsutism/hypertrichosis, sparse scalp hair and varying kind of congenital anomalies. CSS can easily be misdiagnosed as other syndromes or disorders with a similar clinical picture because of their genetic and phenotypic heterogeneity. We describde the genotype-phenotype correlation of one patient from a healthy Chinese family with a novel genotype underlying CSS, who was first diagnosed in the ophthalmology department as early-onset high myopia (eoHM). Comprehensive ophthalmic tests as well as other systemic examinations were performed on participants to confirm the phenotype. The genotype was identified using whole exome sequencing, and further verified the results among other family members by Sanger sequencing. Real-time quantitative PCR (RT-qPCR) technology was used to detect the relative mRNA expression levels of candidate genes between proband and normal family members. The pathogenicity of the identified variant was determined by The American College of Medical Genetics and Genomics (ACMG) guidelines. STRING protein-protein interactions (PPIs) network analysis was used to detect the interaction of candidate gene-related proteins with high myopia gene-related proteins. The patient had excessive eoHM, cone-rod dystrophy, coarse face, excessive hair growth on the face, sparse scalp hair, developmental delay, intellectual disability, moderate hearing loss, dental hypoplasia, patent foramen ovale, chronic non-atrophic gastritis, bilateral renal cysts, cisterna magna, and emotional outbursts with aggression. The genetic assessment revealed that the patient carries a de novo heterozygous frameshift insertion variant in the ARID1B c.3981dup (p.Glu1328ArgfsTer5), which are strongly associated with the typical clinical features of CSS patients. The test results of RT-qPCR showed that mRNA expression of the ARID1B gene in the proband was approximately 30% lower than that of the normal control in the family, suggesting that the variant had an impact on the gene function at the level of mRNA expression. The variant was pathogenic as assessed by ACMG guidelines. Analysis of protein interactions in the STRING online database revealed that the ARID1A protein interacts with the high myopia gene-related proteins FGFR3, ASXL1, ERBB3, and SOX4, whereas the ARID1A protein antagonizes the ARID1B protein. Therefore, in this paper, we are the first to report a de novo heterozygous frameshift insertion variant in the ARID1B gene causing CSS with excessive eoHM. Our study extends the genotypic and phenotypic spectrums for ARID1B-CSS and supplies evidence of significant association of eoHM with variant in ARID1B gene. As CSS has high genetic and phenotypic heterogeneity, our findings highlight the importance of molecular genetic testing and an interdisciplinary clinical diagnostic workup to avoid misdiagnosis as some disorders with similar manifestations of CSS.

Identification of a novel de novo mutation in SOX4 for syndromic tooth agenesis.

OBJECTIVES: Coffin-Siris Syndrome (CSS) is a congenital disorder characterized by delayed growth, dysmorphic facial features, hypoplastic nails and phalanges of the fifth digit, and dental abnormalities. Tooth agenesis has been reported in CSS patients, but the mechanisms regulating this syndromic tooth agenesis remain largely unknown. This study aims to identify the pathogenic mutation of CSS presenting tooth genesis and explore potential regulatory mechanisms. MATERIALS AND METHODS: We utilized whole-exome sequencing to identify variants in a CSS patient, followed by Sanger validation. In silico analysis including conservation analysis, pathogenicity predictions, and 3D structural assessments were carried out. Additionally, single-cell RNA sequencing and fluorescence in situ hybridization (FISH) were applied to explore the spatio-temporal expression of Sox4 expression during murine tooth development. Weighted Gene Co-expression Network Analysis (WGCNA) was employed to examine the functional role of SOX4. RESULTS: A novel de novo SOX4 missense mutation (c.1255C > G, p.Leu419Val) was identified in a Chinese CSS patient exhibiting tooth agenesis. Single-cell RNA sequencing and FISH further verified high expression of Sox4 during murine tooth development, and WGCNA confirmed its central role in tooth development pathways. Enriched functions included cell-substrate junctions, focal adhesion, and RNA splicing. CONCLUSIONS: Our findings link a novel SOX4 mutation to syndromic tooth agenesis in CSS. This is the first report of SOX4 missense mutation causing syndromic tooth agenesis. CLINICAL RELEVANCE: This study not only enhances our understanding of the pathogenic mutation for syndromic tooth agenesis but also provides genetic diagnosis and potential therapeutic insights for syndromic tooth agenesis.

Comparison of PAS and adenoids in patients with and without maxillary micrognathia before orthodontic treatment.

OBJECTIVE: Craniofacial anomalies are widely discussed as predisposing factors of breathing disorders. Since many more cofactors exist, this study investigated the association between maxillary micrognathia and morphological changes of posterior airway space and adenoids in these patients. MATERIAL AND METHODS: Cephalometric radiographs of n = 73 patients were used for data acquisition. The patients were divided into two groups according to certain skeletal characteristics: maxillary micrognathia (n = 34, 16 female, 18 male; mean age 10.55 ± 3.03 years; defined by a SNA angle < 79°) and maxillary eugnathia (n = 39, 19 female, 20 male; mean age 10.93 ± 3.26 years; defined by a SNA angle > 79°). The evaluation included established procedures for measurements of the maxilla, posterior airway space and adenoids. Statistics included Kolmogorov-Smirnov-, T- and Mann-Whitney-U-Tests for the radiographs. The level of significance was set at p < 0.05. RESULTS: The cephalometric analysis showed differences in the superior posterior face height and the depth of the posterior airway space at palatal level among the two groups. The depth of the posterior airway space at mandibular level was the same for both groups, just as the size of the area taken by adenoids in the nasopharynx. CONCLUSIONS: Skeletal anomalies affect the dimension of the posterior airway space. There were differences among the subjects with maxillary micrognathia and these with a normal maxilla. However, the maxilla was only assessed in the sagittal direction, not in the transverse. This study showed that the morphology of the maxilla relates to the posterior airway space whereas the adenoids seem not to be affected. CLINICAL RELEVANCE: Maxillary micrognathia is significantly associated with a smaller depth of the posterior airway space at the palatal level compared to patients with maxillary eugnathia.

Identification of a novel phenotype of external ear deformity related to Coffin-Siris syndrome-9 and literature review.

De novo germline variants of the SRY-related HMG-box 11 gene (SOX11) have been reported to cause Coffin-Siris syndrome-9 (CSS-9), a rare congenital disorder associated with multiple organ malformations, including ear anomalies. Previous clinical and animal studies have found that intragenic pathogenic variant or haploinsufficiency in the SOX11 gene could cause inner ear malformation, but no studies to date have documented the external ear malformation caused by SOX11 deficiency. Here, we reported a Chinese male with unilateral microtia and bilateral sensorineural deafness who showed CSS-like manifestations, including dysmorphic facial features, impaired neurodevelopment, and fingers/toes malformations. Using trio-based whole-exome sequencing, a de novo missense variant in SOX11 (NM_003108.4: c.347A>G, p.Y116C) was identified and classified as pathogenic variant as per American College of Medical Genetics guidelines. Moreover, a systematic search of the literature yielded 12 publications that provided data of 55 SOX11 intragenic variants affecting various protein-coding regions of SOX11 protein. By quantitatively analyzing phenotypic spectrum information related to these 56 SOX11 variants (including our case), we found variants affecting different regions of SOX11 protein (high-mobility group [HMG] domain and non-HMG regions) appear to influence the phenotypic spectrum of organ malformations in CSS-9; variants altering the HMG domain were more likely to cause the widest range of organ anomalies. In summary, this is the first report of CSS with external ear malformation caused by pathogenic variant in SOX11, indicating that the SOX11 gene may be not only essential for the development of the inner ear but also critical for the morphogenesis of the external ear. In addition, thorough clinical examination is recommended for patients who carry pathogenic SOX11 variants that affect the HMG domain, as these variants may cause the widest range of organ anomalies underlying this condition.

Auriculocondylar syndrome 2 caused by a novel PLCB4 variant in a male Chinese neonate: A case report and review of the literature.

BACKGROUND: Auriculocondylar syndrome (ARCND) is a rare congenital craniofacial developmental malformation syndrome of the first and second pharyngeal arches with external ear malformation at the junction between the lobe and helix, micromaxillary malformation, and mandibular condylar hypoplasia. Four subtypes of ARCND have been described so far, that is, ARCND1 (OMIM # 602483), ARCND2 (ARCND2A, OMIM # 614669; ARCND2B, OMIM # 620458), ARCND3 (OMIM # 615706), and ARCND4 (OMIM # 620457). METHODS: This study reports a case of ARCND2 resulting from a novel pathogenic variant in the PLCB4 gene, and summarizes PLCB4 gene mutation sites and phenotypes of ARCND2. RESULTS: The proband, a 5-day-old male neonate, was referred to our hospital for respiratory distress. Micrognathia, microstomia, distinctive question mark ears, as well as mandibular condyle hypoplasia were identified. Trio-based whole-exome sequencing identified a novel missense variant of NM_001377142.1:c.1928C>T (NP_001364071.1:p.Ser643Phe) in the PLCB4 gene, which was predicted to impair the local structural stability with a result that the protein function might be affected. From a review of the literature, only 36 patients with PLCB4 gene mutations were retrieved. CONCLUSION: As with other studies examining familial cases of ARCND2, incomplete penetrance and variable expressivity were observed within different families' heterozygous mutations in PLCB4 gene. Although, motor and intellectual development are in the normal range in the vast majority of patients with ARCND2, long-term follow-up and assessment are still required.

Oral Structural Dysphagia in Children.

Oral causes of dysphagia in infancy may involve the lips, the tongue, or the palate. Whereas ankyloglossia is commonly diagnosed in infants with dysphagia, assessment of the need for surgical intervention may be less straightforward. Tongue size (macroglossia) may be associated with dysphagia as it may cause limitation of movement of the food or milk bolus by the lips or cheeks. Congenital conditions such as cleft lip and palate, micrognathia, or craniofacial microsomia may also be associated with dysphagia. Diagnosis and treatment of these conditions can be improved with the engagement of lactation and feeding experts as well as multidisciplinary craniofacial teams.

A second hotspot for pathogenic exon-skipping variants in CDC45.

Biallelic pathogenic variants in CDC45 are associated with Meier-Gorlin syndrome with craniosynostosis (MGORS type 7), which also includes short stature and absent/hypoplastic patellae. Identified variants act through a hypomorphic loss of function mechanism, to reduce CDC45 activity and impact DNA replication initiation. In addition to missense and premature termination variants, several pathogenic synonymous variants have been identified, most of which cause increased exon skipping of exon 4, which encodes an essential part of the RecJ-orthologue's DHH domain. Here we have identified a second cohort of families segregating CDC45 variants, where patients have craniosynostosis and a reduction in height, alongside common facial dysmorphisms, including thin eyebrows, consistent with MGORS7. Skipping of exon 15 is a consequence of two different variants, including a shared synonymous variant that is enriched in individuals of East Asian ancestry, while other variants in trans are predicted to alter key intramolecular interactions in α/ß domain II, or cause retention of an intron within the 3'UTR. Our cohort and functional data confirm exon skipping is a relatively common pathogenic mechanism in CDC45, and highlights the need for alternative splicing events, such as exon skipping, to be especially considered for variants initially predicted to be less likely to cause the phenotype, particularly synonymous variants.

Mandibular Distraction Osteogenesis in Children and Adolescents: A Clinical and Radiographic Research Using Cone-Beam Computed Tomography.

AIM: The aim of this cross-sectional study was to evaluate, via cone-beam computed tomography, the long-term postoperative outcome in children treated with mandibular distraction osteogenesis. MATERIALS AND METHODS: All young patients treated with mandibular distraction osteogenesis (MDO), during a 16-year period, at the University Department of Oral and Maxillofacial Surgery of a Pediatric Hospital, were recalled, and various clinical and radiographic parameters were recorded. RESULTS: Eleven patients were included: 5 with hemifacial microsomia (HFM) and 6 with mandibular micrognathia. In all cases, MDO had been successful in regular follow-up and decannulation, soon after MDO, was achieved in all tracheostomy cases. The long-term result in cases of HFM was found stable, functionally and esthetically accepted, although less satisfactory than in regular follow-up; in micrognathia patients, relapse of different degrees was registered in 4 of 6 cases, without any need for tracheostomy though. Detailed and accurate information was obtained by cone-beam computed tomography (CBCT). The shape of the regenerated bone was irregular in HFM cases and relatively normal in the micrognathia cases. Quality of the regenerated bone was normal in all patients. The irregular shape registered in HFM cases did not compromise a safe orthognathic operation. CONCLUSIONS: Distraction osteogenesis remains an early treatment choice in cases of mandibular deformities. Long-term findings showed that there is a degree of relapse with growth, which was more obvious in mandibular micrognathia cases. Computed tomography contributes to detailed evaluation of changes at the distraction site.

Protein destabilization underlies pathogenic missense mutations in ARID1B.

ARID1B is a SWI/SNF subunit frequently mutated in human Coffin-Siris syndrome (CSS) and it is necessary for proliferation of ARID1A mutant cancers. While most CSS ARID1B aberrations introduce frameshifts or stop codons, the functional consequence of missense mutations found in ARID1B is unclear. We here perform saturated mutagenesis screens on ARID1B and demonstrate that protein destabilization is the main mechanism associated with pathogenic missense mutations in patients with Coffin-Siris Syndrome.

Soft-tissue, non-osteogenic distraction of the mandible and lower face in bilateral hemifacial microsomia-technical report.

The aim of this study is to present a sequential strategy of soft-tissue, non-osteogenic distraction with a novel device, followed by microvascular bony reconstruction for severe cases of mandibular hypoplasia. The case of a 21-year-old woman with Goldenhar syndrome is presented, whose mandible remained severely hypoplastic despite previous attempts at distraction and was not suitable for further osteogenic distraction. Soft tissue deficiency and pin track scarring prevented free fibular transfers. A personalized distractor, anchored to the cranium and the mandibular symphysis, was designed to expand the soft tissues while allowing for physiological temporomandibular joint (TMJ) movement without compression forces. Internal distractors were placed along the osteotomies to prevent condylar luxation. After completion of the soft tissue distraction, the native mandible was resected except for the condyles and reconstructed with two free fibula flaps. This report represents the proof of concept of a sequential approach to severe lower face soft-tissue and bone deficiency, which preserves TMJ function and avoids the transfer of poorly matched skin to the face.

Correlation of Cerebrospinal Fluid Total Protein and Serum Neutrophil-to-Lymphocyte Ratio with Clinical Outcomes of Guillain-Barre Syndrome Variants.

OBJECTIVE: To evaluate the correlation of cerebrospinal fluid total protein and serum neutrophil-to-lymphocyte ratio with the clinical outcomes and the various clinical and electrophysiological variants of Guillain-Barre syndrome. STUDY DESIGN: Cross-sectional study. Place and Duration of the Study: Department of Neurology, Mayo Hospital and King Edward Medical University, Lahore, Pakistan, from November 2022 to April 2023. METHODOLOGY: Fourty-six Guillain-Barre syndrome patients, aged 12-70 years, were included in the study diagnosed by using the Brighton's criteria. Functional disability and respiratory insufficiency were assessed by using the modified Hughes disability score and the Erasmus Guillain-Barre syndrome respiratory insufficiency score, respectively. Serum neutrophil-to-lymphocyte ratio and cerebrospinal fluid total protein were calculated for each patient at the time of admission. RESULTS: Axonal variants had a higher mean neutrophil-to-lymphocyte ratio (5.29 ± 4.38) than demyelinating variants (4.71 ± 3.4) and Miller-Fischer syndrome (3 ± 2.828). This ratio was positively correlated with the modified Hughes's disability score (r = 0.790, p = 0.001) and the Erasmus Guillain-Barre syndrome respiratory insufficiency score (r = 0.936, p = 0.002). Mean cerebrospinal fluid total protein was higher for demyelinating (218 ± 136 mg/dl) than axonal variants (86 ± 56 mg/dl) and Miller-Fischer syndrome (34 ± 21 mg/dl). However, higher modified Hughes disability score (4-6) (r = 0.020, p = 0.117) and a high Erasmus Guillain-Barre syndrome respiratory insufficiency score (5-7) (r = 0.115, p = 0.302) did not significantly affect mean cerebrospinal fluid total proteins. CONCLUSION: Serum neutrophil-to-lymphocyte ratio can be regarded as a reliable biomarker to assess disease severity and clinical outcome in Guillain-Barre syndrome. Cerebrospinal fluid total protein is a poor predictor of the prognosis and severity of Guillain-Barre syndrome. KEY WORDS: Guillain-Barre syndrome (GBS), Clinical outcome, Cerebrospinal fluid total protein (CSF-TP), Neutrophil-to-lymphocytic ratio (NLR), Prognostic biomarker.

ARID2, a milder cause of Coffin-Siris Syndrome? Broadening the phenotype with 17 additional individuals.

Coffin-Siris Syndrome (CSS, MIM 135900) is now a well-described genetic condition caused by pathogenic variants in the Bromocriptine activating factor (BAF) complex, including ARID1B, ARID1A, ARID2, SMARCA4, SMARCE1, SMARCB1, SOX11, SMARCC2, DPF2, and more recently, BICRA. Individuals with CSS have a spectrum of various medical challenges, most often evident at birth, including feeding difficulties, hypotonia, organ-system anomalies, and learning and developmental differences. The classic finding of fifth digit hypo- or aplasia is seen variably. ARID2, previously described, is one of the less frequently observed gene changes in CSS. Although individuals with ARID2 have been reported to have classic features of CSS including hypertrichosis, coarse facial features, short stature, and fifth digit anomalies, as with many of the other CSS genes, there appears to be a spectrum of phenotypes. We report here a cohort of 17 individuals with ARID2 variants from the Coffin-Siris/BAF clinical registry and detail their medical challenges as well as developmental progress. Feeding difficulties, hypotonia, and short stature occur often, and hip dysplasia appears to occur more often than with other genes, however more severe medical challenges such as significant brain and cardiac malformations are rarer. Individuals appear to have mild to moderate intellectual impairment and may carry additional diagnoses such as ADHD. Further phenotypic description of this gene will aid clinicians caring for individuals with this rarer form of CSS.

Difficult intubation in syndromic versus nonsyndromic forms of micrognathia in children.

BACKGROUND: We investigated how syndromic versus nonsyndromic forms of micrognathia impacted difficult intubation outcomes in children. Primary outcome was the first-attempt success rate of tracheal intubation, secondary outcomes were number of intubation attempts and complications. We hypothesized that syndromic micrognathia would be associated with lower first-attempt success rate. METHODS: In micrognathic patients enrolled in the Pediatric Difficult Intubation Registry (08/2012-03/2019) we retrospectively compared demographic and clinical characteristics between children with nonsyndromic and syndromic micrognathia using standardized mean differences (SMD) and assessed the association of the presence of syndrome with the primary and secondary outcomes using propensity score matching analysis with and without matching for airway assessment findings. RESULTS: Nonsyndromic patients (628) were less likely to have additional airway abnormalities. Syndromic patients (216) were less likely to have unanticipated difficult intubation (2% vs. 20%, SMD 0.59). First-attempt success rates of intubation were: 38% in the syndromic versus 34% in the nonsyndromic group (odds ratio [OR] 1.18; 95% confidence intervals [95% CI] 0.74, 1.89; p = .478), and 37% versus 37% (OR 0.99; 95% CI 0.66, 1.48; p = .959). Median number of intubation attempts were 2 (interquartile range [IQR]: 1, 3; range: 1, 8) versus 2 (IQR: 1, 3; range 1, 12) (median regression coefficient = 0; 95% CI: -0.7, 0.7; p = .999) and 2 (IQR: 1, 3; range: 1, 12) versus 2 (IQR: 1, 3; range 1, 8) (median regression coefficient = 0; 95% CI: -0.5, 0.5; p = .999). Complication rates were 14% versus 22% (OR 0.6; 95% CI 0.34, 1.04; p = .07) and 16% versus 21% (OR 0.71; 95% CI 0.43, 1.17; p = .185). CONCLUSIONS: Presence of syndrome was not associated with lower first-attempt success rate on intubation, number of intubation attempts, or complication rate among micrognathic patients difficult to intubate, despite more associated craniofacial abnormalities. Nonsyndromic patients were more likely to have unanticipated difficult intubations, first attempt with direct laryngoscopy.

[Genetic analysis of two children with Coffin-Siris syndrome due to variants of ARID1B gene].

OBJECTIVE: To explore the genetic basis of two children with unexplained psychomotor developmental delay and facial dysmorphisms suggestive of Coffin-Siris syndrome (CSS). METHODS: A boy and a girl suspected for CSS at the 980th Hospital of the People's Liberation Army Joint Service Support Force respectively in July 2019 and January 2021, and seven members from their families, were selected as the study subjects. Clinical data and family history of the children were collected, and detailed physical examination was carried out, in addition with laboratory and related auxiliary examinations. Potential variants and copy number variations (CNVs) were detected by whole exome sequencing (WES) and copy number variation sequencing (CNV-seq). RESULTS: Child 1, an 8-month-old female, had featured microcephaly, atrial septal defect, curving of fifth finger/toe, and low limb muscle tone. Child 2 was a 2.5-year-old male with language delay, social impairment, dense hair but no curving of the fifth fingers. Genetic testing revealed that child 1 had loss of heterozygosity for exons 8 to 21 of the ARID1B gene, which was unreported previously. Family verification showed that both of her parents were of the wild type. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG) and American Society of Molecular Pathology (AMP), the variant was rated as pathogenic (PVS1+PS2+PM2-supporting). Child 2 was found to harbor a heterozygous c.4263-6 (IVS17) T>G variant of the ARID1B gene. Transcriptome sequencing confirmed that the variant can affect the normal splicing, resulting in retention of a 5 bp sequence in intron 17. Family verification showed that both of his parents were of the wild type. Based on the guidelines from the ACMG, the variant was rated as pathogenic (PS2+PM2-supporting+PP3+PS3). CONCLUSION: WES and RNA-seq have confirmed the diagnosis of CSS in both children. Discovery of the novel variants has expanded the spectrum of pathogenic mutations underlying CSS, and provided a basis for the genetic counseling.