PHF6-mediated transcriptional control of NSC via Ephrin receptors is impaired in the intellectual disability syndrome BFLS.

The plant homeodomain zinc-finger protein, PHF6, is a transcriptional regulator, and PHF6 germline mutations cause the X-linked intellectual disability (XLID) Börjeson-Forssman-Lehmann syndrome (BFLS). The mechanisms by which PHF6 regulates transcription and how its mutations cause BFLS remain poorly characterized. Here, we show genome-wide binding of PHF6 in the developing cortex in the vicinity of genes involved in central nervous system development and neurogenesis. Characterization of BFLS mice harbouring PHF6 patient mutations reveals an increase in embryonic neural stem cell (eNSC) self-renewal and a reduction of neural progenitors. We identify a panel of Ephrin receptors (EphRs) as direct transcriptional targets of PHF6. Mechanistically, we show that PHF6 regulation of EphR is impaired in BFLS mice and in conditional Phf6 knock-out mice. Knockdown of EphR-A phenocopies the PHF6 loss-of-function defects in altering eNSCs, and its forced expression rescues defects of BFLS mice-derived eNSCs. Our data indicate that PHF6 directly promotes Ephrin receptor expression to control eNSC behaviour in the developing brain, and that this pathway is impaired in BFLS.

Recognition of Genetic Conditions After Learning With Images Created Using Generative Artificial Intelligence.

Importance: The lack of standardized genetics training in pediatrics residencies, along with a shortage of medical geneticists, necessitates innovative educational approaches. Objective: To compare pediatric resident recognition of Kabuki syndrome (KS) and Noonan syndrome (NS) after 1 of 4 educational interventions, including generative artificial intelligence (AI) methods. Design, Setting, and Participants: This comparative effectiveness study used generative AI to create images of children with KS and NS. From October 1, 2022, to February 28, 2023, US pediatric residents were provided images through a web-based survey to assess whether these images helped them recognize genetic conditions. Interventions: Participants categorized 20 images after exposure to 1 of 4 educational interventions (text-only descriptions, real images, and 2 types of images created by generative AI). Main Outcomes and Measures: Associations between educational interventions with accuracy and self-reported confidence. Results: Of 2515 contacted pediatric residents, 106 and 102 completed the KS and NS surveys, respectively. For KS, the sensitivity of text description was 48.5% (128 of 264), which was not significantly different from random guessing (odds ratio [OR], 0.94; 95% CI, 0.69-1.29; P = .71). Sensitivity was thus compared for real images vs random guessing (60.3% [188 of 312]; OR, 1.52; 95% CI, 1.15-2.00; P = .003) and 2 types of generative AI images vs random guessing (57.0% [212 of 372]; OR, 1.32; 95% CI, 1.04-1.69; P = .02 and 59.6% [193 of 324]; OR, 1.47; 95% CI, 1.12-1.94; P = .006) (denominators differ according to survey responses). The sensitivity of the NS text-only description was 65.3% (196 of 300). Compared with text-only, the sensitivity of the real images was 74.3% (205 of 276; OR, 1.53; 95% CI, 1.08-2.18; P = .02), and the sensitivity of the 2 types of images created by generative AI was 68.0% (204 of 300; OR, 1.13; 95% CI, 0.77-1.66; P = .54) and 71.0% (247 of 328; OR, 1.30; 95% CI, 0.92-1.83; P = .14). For specificity, no intervention was statistically different from text only. After the interventions, the number of participants who reported being unsure about important diagnostic facial features decreased from 56 (52.8%) to 5 (7.6%) for KS (P < .001) and 25 (24.5%) to 4 (4.7%) for NS (P < .001). There was a significant association between confidence level and sensitivity for real and generated images. Conclusions and Relevance: In this study, real and generated images helped participants recognize KS and NS; real images appeared most helpful. Generated images were noninferior to real images and could serve an adjunctive role, particularly for rare conditions.

Effects of cleft lip on visual scanning and neural processing of infant faces.

Infant faces readily capture adult attention and elicit enhanced neural processing, likely due to their importance evolutionarily in facilitating bonds with caregivers. Facial malformations have been shown to impact early infant-caregiver interactions negatively. However, it remains unclear how such facial malformations may impact early visual processing. The current study used a combination of eye tracking and electroencephalography (EEG) to investigate adults' early visual processing of infant faces with cleft lip/palate as compared to normal infant faces, as well as the impact cleft palate has on perceived cuteness. The results demonstrated a significant decrease in early visual attention to the eye region for infants with cleft palate, while increased visual attention is registered on the mouth region. Increased neural processing of the cleft palate was evident at the N170 and LPP, suggesting differences in configural processing and affective responses to the faces. Infants with cleft palate were also rated significantly less cute than their healthy counterparts (mean difference = .73, p < .001). These results suggest that infants' faces with cleft lip/palate are processed differently at early visual perception. These processing differences may contribute to several important aspects of development (e.g., joint attention) and may play a vital role in the previously observed difficulties in mother-infant interactions.

[Analysis of a case of Kabuki syndrome due to a novel variant of KMT2D gene].

OBJECTIVE: To report on a case of Kabuki syndrome (KS) due to a novel variant of KMT2D gene. METHODS: A child diagnosed with KS at the Fujian Children's Hospital on July 25, 2022 was selected as the study subject. Whole exome sequencing was carried out for the child and her parents. Candidate variant was validated by Sanger sequencing and bioinformatic analysis. RESULTS: The child, a 4-month-old female, had presented with distinctive facial features, growth retardation, cardiac malformations, horseshoe kidney, hypothyroidism, and recurrent aspiration pneumonia. Whole exome sequencing revealed that she has harbored a heterozygous c.6285dup (p.Lys2096Ter) variant of the KMT2D gene. Sanger sequencing confirmed that neither of her parents had carried the same variant. The variant was previously unreported and may result in a truncated protein and loss of an enzymatic activity region. The corresponding site of the variant is highly conserved. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was classified as pathogenic (PVS1+PS2+PM2_Supporting). CONCLUSION: The c.6285dup variant of the KMT2D gene probably underlay the KS in this child.

Partial facial duplication (diprosopus): a case report and review of the literature.

BACKGROUND: Diprosopus, or craniofacial duplication, is a rare entity that occurs in approximately 1 in 180,000 to 15 million live births. The degree of duplication varies from complete facial duplication to small facial structure duplication like the nose and eye. The cause of diprosopus is unknown though there are proposed factors. CASE PRESENTATION: Our African patient was a term 72 hours old female neonate who was referred to our center with impression of lower facial duplication with two oral cavity that are located side to side separated by large soft tissue, she also had flat nasal bridge with widely separated nostrils and widely spaced eyes. Besides the facial malformation she had multiple episodes of vomiting with aspiration. Her blood tests were normal. Precontract brain computed tomography (CT) scan confirmed partially duplicated mandible and maxilla, two oral cavity separated by large fatty tissue, brain tissue were well formed and the only abnormality was corpus callosum agenesis and interhemispheric lipoma. In her stay at hospital nasogastric tube (NG) tube feed was initiated and started with antibiotics for aspiration pneumonia. After 25th day the neonatal passed away with possible cause of death being respiratory failure. CONCLUSION: Craniofacial duplication is a very rare anomaly with only a few cases reported. Most of these patients are stillborn, even if they survive the prognosis is often poor. Early prenatal diagnosis is very important as termination of pregnancy can sometimes be considered an option.

Sex-specific difference in phenotype of Kabuki syndrome type 2 patients: a matched case-control study.

BACKGROUND: Kabuki syndrome (KS) is a monogenic disorder leading to special facial features, mental retardation, and multiple system malformations. Lysine demethylase 6A, (KDM6A, MIM*300128) is the pathogenic gene of Kabuki syndrome type 2 (KS2, MIM#300867), which accounts for only 5%-8% of KS. Previous studies suggested that female patients with KS2 may have a milder phenotype. METHOD: We summarized the phenotype and genotype of KS2 patients who were diagnosed in Shanghai Children's Medical Center since July 2017 and conducted a 1:3 matched case-control study according to age and sex to investigate sex-specific differences between patients with and without KS2. RESULTS: There were 12 KS2 cases in this study, and 8 of them matched with 24 controls. The intelligence quotient (IQ) score of the case group was significantly lower than that of the control group (P < 0.001). In addition, both the incidence of intellectual disability (ID) (IQ < 70) and moderate-to-severe ID (IQ < 55) were significantly higher in the case group than those in the control group. No sex-specific difference was found in the incidence of ID or moderate-to-severe ID between the female cases and female controls, whereas there was a significant difference between male cases and male controls. Furthermore, the rate of moderate-to-severe ID and congenital heart disease (CHD) was significantly higher in the male group than that in the female group. CONCLUSIONS: Our results showed that a sex-specific difference was exhibited in the clinical phenotypes of KS2 patients. The incidence of CHD was higher in male patients, and mental retardation was significantly impaired. However, the female patients' phenotype was mild.

DNMT3B PWWP mutations cause hypermethylation of heterochromatin.

The correct establishment of DNA methylation patterns is vital for mammalian development and is achieved by the de novo DNA methyltransferases DNMT3A and DNMT3B. DNMT3B localises to H3K36me3 at actively transcribing gene bodies via its PWWP domain. It also functions at heterochromatin through an unknown recruitment mechanism. Here, we find that knockout of DNMT3B causes loss of methylation predominantly at H3K9me3-marked heterochromatin and that DNMT3B PWWP domain mutations or deletion result in striking increases of methylation in H3K9me3-marked heterochromatin. Removal of the N-terminal region of DNMT3B affects its ability to methylate H3K9me3-marked regions. This region of DNMT3B directly interacts with HP1α and facilitates the bridging of DNMT3B with H3K9me3-marked nucleosomes in vitro. Our results suggest that DNMT3B is recruited to H3K9me3-marked heterochromatin in a PWWP-independent manner that is facilitated by the protein's N-terminal region through an interaction with a key heterochromatin protein. More generally, we suggest that DNMT3B plays a role in DNA methylation homeostasis at heterochromatin, a process which is disrupted in cancer, aging and Immunodeficiency, Centromeric Instability and Facial Anomalies (ICF) syndrome.

Next generation phenotyping for diagnosis and phenotype-genotype correlations in Kabuki syndrome.

The field of dysmorphology has been changed by the use Artificial Intelligence (AI) and the development of Next Generation Phenotyping (NGP). The aim of this study was to propose a new NGP model for predicting KS (Kabuki Syndrome) on 2D facial photographs and distinguish KS1 (KS type 1, KMT2D-related) from KS2 (KS type 2, KDM6A-related). We included retrospectively and prospectively, from 1998 to 2023, all frontal and lateral pictures of patients with a molecular confirmation of KS. After automatic preprocessing, we extracted geometric and textural features. After incorporation of age, gender, and ethnicity, we used XGboost (eXtreme Gradient Boosting), a supervised machine learning classifier. The model was tested on an independent validation set. Finally, we compared the performances of our model with DeepGestalt (Face2Gene). The study included 1448 frontal and lateral facial photographs from 6 centers, corresponding to 634 patients (527 controls, 107 KS); 82 (78%) of KS patients had a variation in the KMT2D gene (KS1) and 23 (22%) in the KDM6A gene (KS2). We were able to distinguish KS from controls in the independent validation group with an accuracy of 95.8% (78.9-99.9%, p < 0.001) and distinguish KS1 from KS2 with an empirical Area Under the Curve (AUC) of 0.805 (0.729-0.880, p < 0.001). We report an automatic detection model for KS with high performances (AUC 0.993 and accuracy 95.8%). We were able to distinguish patients with KS1 from KS2, with an AUC of 0.805. These results outperform the current commercial AI-based solutions and expert clinicians.

BTB domain mutations perturbing KCTD15 oligomerisation cause a distinctive frontonasal dysplasia syndrome.

INTRODUCTION: KCTD15 encodes an oligomeric BTB domain protein reported to inhibit neural crest formation through repression of Wnt/beta-catenin signalling, as well as transactivation by TFAP2. Heterozygous missense variants in the closely related paralogue KCTD1 cause scalp-ear-nipple syndrome. METHODS: Exome sequencing was performed on a two-generation family affected by a distinctive phenotype comprising a lipomatous frontonasal malformation, anosmia, cutis aplasia of the scalp and/or sparse hair, and congenital heart disease. Identification of a de novo missense substitution within KCTD15 led to targeted sequencing of DNA from a similarly affected sporadic patient, revealing a different missense mutation. Structural and biophysical analyses were performed to assess the effects of both amino acid substitutions on the KCTD15 protein. RESULTS: A heterozygous c.310G>C variant encoding p.(Asp104His) within the BTB domain of KCTD15 was identified in an affected father and daughter and segregated with the phenotype. In the sporadically affected patient, a de novo heterozygous c.263G>A variant encoding p.(Gly88Asp) was present in KCTD15. Both substitutions were found to perturb the pentameric assembly of the BTB domain. A crystal structure of the BTB domain variant p.(Gly88Asp) revealed a closed hexameric assembly, whereas biophysical analyses showed that the p.(Asp104His) substitution resulted in a monomeric BTB domain likely to be partially unfolded at physiological temperatures. CONCLUSION: BTB domain substitutions in KCTD1 and KCTD15 cause clinically overlapping phenotypes involving craniofacial abnormalities and cutis aplasia. The structural analyses demonstrate that missense substitutions act through a dominant negative mechanism by disrupting the higher order structure of the KCTD15 protein complex.

Hearing characteristics and otoradiological abnormalities in three patients with novel pathogenic variants of KMT2D-related Kabuki syndrome.

BACKGROUND: Kabuki syndrome 1 (KS1; OMIM:147920), which is characterized by distinctive dysmorphic facial features (such as arched eyebrows, long palpebral fissures with eversion of the lower lid, and large protuberant ears), intellectual disability, short stature, and dermatoglyphic and skeletal abnormalities, is brought on by pathogenic variants in KMT2D (OMIM:602113). In this work, three individuals with novel pathogenic KMT2D gene variants had their longitudinal audiological manifestations and ear structural characteristics outlined. METHODS: The longitudinal audiological data from neonatal hearing screening and a battery of several hearing tests were evaluated. The battery of hearing tests included tympanometry, distortion product otoacoustic emission (DPOAE), click-evoked air-conduction auditory brain-stem response (AC-ABR), click-evoked bone-conduction auditory brain-stem response (BC-ABR), narrow band CE-chirp auditory steady-state response (NB CE-chirp ASSR), and pure-tone audiometry (PTA). Phenotype identification and whole exome sequencing (WES) were performed on recruited individuals. RESULTS: All three patients (two females and on male; last evaluations at 14 months, 11 months, and 5.7 years, respectively) failed the newborn hearing screening, and the audiological follow-up data revealed mild to profound fluctuating hearing loss, which was directly influenced by the incidence and severity of otitis media with effusion (OME). When OME occurred, the AC-ABR thresholds increased from 30-75 dBnHL to 45-90 dBnHL. The threshold for the BC-ABR and BC-PTA was between 25 and 50 dBnHL, indicating mild to moderate sensorineural hearing loss (SNHL). The high-resolution computed tomography (HRCT) pictures indicated that all three patients had middle and inner ear abnormalities. Middle ear anomalies showed as diminished mastoid gasification and ossicle dysplasia. Cochlear dysplasia, a dilated vestibule, fusion of the vestibule with the horizontal semicircular canals, and a short and thick horizontal semicircular canal were visible on images of the inner ear. This study recruited three individuals with three novel pathogenic variants (c.5104C>T, c.10205delA, and c.12840delC) of KMT2D who were identified at ages 27 days, 2 months, and 5.5 years. CONCLUSIONS: Hearing characteristics of three individuals with three novel pathogenic variants of KMT2D range from mild to profound fluctuating hearing loss with mild to moderate SNHL. HRCT scans showed that all three individuals had anatomical middle and inner ear abnormalities. KS 1 patients must get clinical therapy for OME, frequent auditory monitoring, and prompt intervention.

Attention challenges in Kabuki syndrome.

BACKGROUND: Understanding the specific neurobehavioural profile of rare genetic diseases enables clinicians to provide the best possible care for patients and families, including prognostic and treatment advisement. Previous studies suggested that a subset of individuals with Kabuki syndrome (KS), a genetic disorder causing intellectual disability and other neurodevelopmental phenotypes, have attentional deficits. However, these studies looked at relatively small numbers of molecularly confirmed cases and often used retrospective clinical data instead of standardised assessments. METHODS: Fifty-five individuals or caregivers of individuals with molecularly confirmed KS completed assessments to investigate behaviour and adaptive function. Additionally, information was collected on 23 unaffected biological siblings as controls. RESULTS: Attention Problems in children was the only behavioural category that, when averaged, was clinically significant, with the individual scores of nearly 50% of the children with KS falling in the problematic range. Children with KS scored significantly higher than their unaffected sibling on nearly all behavioural categories. A significant correlation was found between Attention Problems scores and adaptive function scores (P = 0.032), which was not explained by lower general cognitive ability. CONCLUSIONS: We found that the rates of children with attentional deficits are much more elevated than would be expected in the general population, and that attention challenges are negatively correlated with adaptive function. When averaged across KS participants, none of the behavioural categories were in the clinically significant range except Attention Problems for children, which underscores the importance of clinicians screening for attention deficit hyperactivity disorder (ADHD) in children with KS.

Cardiovascular anomalies in patients with Tessier syndrome: a systematic review.

Tessier clefts are skeletal and soft tissue abnormalities of a neonate's facial structures. They could be classified as syndromic and non-syndromic clefts, which can be attributed to disruptions in fetal development and genetic mutations, respectively. Reported cases of these clefts typically document the presence of additional abnormalities associated with these clefts. In this systematic review, we analyzed reports of Tessier clefts accompanied by cardiovascular anomalies, as one of the commonly encountered anomalies. We systematically searched PubMed (MEDLINE), Scopus, Web of Science, Science Direct, and Google Scholar. We selected and included case reports, case series, and case reviews on patients with Tessier cleft and cardiovascular anomalies. The critical appraisal of the included studies was performed by two independent investigators using the Consensus-based Clinical Case Reporting Guideline Development (CARE) checklist. Overall, 20 reports (18 case reports and 2 case series) were eligible for inclusion in this review. Tessier clefts 3 and 30 were the most commonly observed. In addition, the most prevalent cardiovascular anomalies consisted of the ventricular septal defect (VSD), double-outlet right ventricle, and atrial septal defect (ASD). Most of the patients received cosmetic and cardiovascular surgeries. However, some were not proper candidates for cardiovascular surgery because of their unstable condition and therefore did not survive.   Conclusion: Regardless of the focus placed on the cleft and subsequent plastic surgery procedures in these cases, it is important to prioritize other abnormalities that may be associated with mortality. A complete cardiovascular system and associated disorders assessment should be performed before facial cosmetic surgeries. What is Known: • Tessier clefts are congenital defects in the soft tissues and bones of the face and like many other congenital defects, they are accompanied by defects in other parts of the body. • In the current literature, the emphasis is on clefts and the cosmetic issues rather than the coinciding defects, particularly cardiovascular anomalies. What is New: • Review the cardiovascular anomalies that are commonly encountered in patients with Tessier clefts.

Craniosynostosis in molecularly diagnosed Kabuki syndrome: Prevalence and clinical implications.

Kabuki syndrome (KS) is characterized by growth impairment, psychomotor delay, congenital heart disease, and distinctive facial features. KMT2D and KDM6A have been identified as the causative genes of KS. Craniosynostosis (CS) has been reported in individuals with KS; however, its prevalence and clinical implications remain unclear. In this retrospective study, we investigated the occurrence of CS in individuals with genetically diagnosed KS and examined its clinical significance. Among 42 individuals with genetically diagnosed KS, 21 (50%) exhibited CS, with 10 individuals requiring cranioplasty. No significant differences were observed based on sex, causative gene, and molecular consequence among individuals with KS who exhibited CS. Both individuals who underwent evaluation with three-dimensional computed tomography (3DCT) and those who required surgery tended to exhibit cranial dysmorphology. Notably, in several individuals, CS was diagnosed before KS, suggesting that CS could be one of the clinical features by which clinicians can diagnose KS. This study highlights that CS is one of the noteworthy complications in KS, emphasizing the importance of monitoring cranial deformities in the health management of individuals with KS. The findings suggest that in individuals where CS is a concern, conducting 3DCT evaluations for CS and digital impressions are crucial.

Delineation of the adult phenotype of Coffin-Siris syndrome in 35 individuals.

Coffin-Siris syndrome (CSS) is a rare multisystemic autosomal dominant disorder. Since 2012, alterations in genes of the SWI/SNF complex were identified as the molecular basis of CSS, studying largely pediatric cohorts. Therefore, there is a lack of information on the phenotype in adulthood, particularly on the clinical outcome in adulthood and associated risks. In an international collaborative effort, data from 35 individuals ≥ 18 years with a molecularly ascertained CSS diagnosis (variants in ARID1B, ARID2, SMARCA4, SMARCB1, SMARCC2, SMARCE1, SOX11, BICRA) using a comprehensive questionnaire was collected. Our results indicate that overweight and obesity are frequent in adults with CSS. Visual impairment, scoliosis, and behavioral anomalies are more prevalent than in published pediatric or mixed cohorts. Cognitive outcomes range from profound intellectual disability (ID) to low normal IQ, with most individuals having moderate ID. The present study describes the first exclusively adult cohort of CSS individuals. We were able to delineate some features of CSS that develop over time and have therefore been underrepresented in previously reported largely pediatric cohorts, and provide recommendations for follow-up.

El enigma de la enfermedad de Enrique IV, rey de Castilla: ¿padeció síndrome de McCune-Albright/displasia fibrosa? / The enigma of Henry IV's disease: Did he suffer from McCune-Albright syndrome/fibrous dysplasia?

Introducción: Enrique IV Rey de Castilla, último rey de la dinastía Trastámara, era hermano de Isabel la Católica. Se le conoce como «el impotente». Basándose en las descripciones previas de los historiadores y biógrafos, Gregorio Marañón en 1922 lo catalogó de «Displásico eunucoide con reacción acromegálica y con netos rasgos esquizoides». Métodos: En 1946 se realizó una inspección post mortem del cadáver momificado hallado en el Monasterio de Guadalupe. Se dejó constancia de un documento escrito y algunas fotografías. Hemos recogido los signos y síntomas descritos y aplicado la clasificación internacional de las enfermedades recomendada por la Organización mundial de la Salud, CIE11-2023. También nos hemos apoyado en las monedas emitidas en el monetario de Enrique IV, en las que hemos identificado aumento de la glándula tiroides. Resultados: Con los datos que están accesibles hasta este momento, sugerimos que Enrique IV padeció de forma altamente probable: displasia ósea facial y poliostótica, cifosis, cojera de una extremidad, alteraciones endocrinas múltiples, acromegalia con macrognatia, enfermedad nodular tiroidea, diaforesis maloliente, disfunción eréctil, hipospadias, desarrollo sexual anómalo, «pelvis feminoide», cólicos abdominales, oligodoncia y desplazamientos dentales. Es posible que también padeciera: pubertad precoz, litiasis renal con fosfaturia debilitante, túnel carpiano, trombocitopenia e hiperplasia o adenoma hipofisario productor de hormona de crecimiento. Conclusión: Sugerimos que Enrique IV pudo sufrir un síndrome de McCune-Albrigth asociado a Displasia fibrosa, una enfermedad rara debida a mutaciones activadoras de función en el gen GNAS.(AU)

Background: Henry IV King of Castile, last king of the Trastámara dynasty, was the brother of Isabella the Catholic. He is known as “the impotent”. Based on previous descriptions by historians and biographers, Gregorio Marañón in 1922 described him as “eunuchoid dysplastic with acromegalic reaction and clear schizoid features”. Methods: In 1946, a post-mortem inspection was carried out on the mummified corpse found in the Monastery of Guadalupe. A written document and some photographs were recorded. We have collected the signs and symptoms described and applied the international classification of diseases recommended by the World Health Organisation, ICD11-2023. We have relied on the coins issued in the money of Henry IV, on which we have identified enlargement of the thyroid gland. Results: With the data available at this time, we suggest that Henry IV most probably suffered from: facial and polyostotic bone dysplasia, kyphosis, limb limping, multiple endocrine disorders, acromegaly with macrognatia, nodular thyroid disease, malodorous diaphoresis, erectile dysfunction, hypospadias, abnormal sexual development, “feminoid pelvis”, abdominal colic, oligodontia and dental displacement. It is possible that he also suffered from: precocious puberty, renal lithiasis with debilitating phosphaturia, carpal tunnel, thrombopenia and growth hormone-producing pituitary hyperplasia or adenoma. Conclusion: We suggest that Henry IV may have suffered from McCune–Albrigth syndrome associated with fibrous dysplasia, a rare disease due to gain-of-function mutations in the GNAS gene.(AU)

Intraoral findings of a patient with Nablus mask-like facial syndrome and dental treatment approaches: a case report and literature review.

Nablus mask-like facial syndrome (NMLFS) (OMIM: 608156) is an extremely rare genetic syndrome first reported by Ahmad Teebi in 2000. Although it is a rare condition, it is characterized by distinctive facial features such as, expressionless facial appearance, tight, glistening facial skin, low anterior hairline, sparse eyebrows, small palpebral fissures (blepharophimosis), hypertolerism, bulbous nose with prominent columella, abnormally short nose and flat nasal bridge, abnormal ear configuration, bilateral longitudinal cheek dimples, everted lower lip, long philtrum, and maxillary hypoplasia. In addition, a happy and friendly disposition is considered to be the common symptom of this syndrome. Previous studies revealing the intraoral findings of this rare symptom are inadequate and the present report is the first one that presents a dental case involving Nablus syndrome in detail. The aim of this report is to contribute to the current literature through our oral findings in an NMFLS patient, presented at our clinic with toothache and through our treatment approach.

Molecular insights of KMT2D and clinical aspects of Kabuki syndrome type 1.

BACKGROUND: Kabuki syndrome type 1 (KS1), a rare multisystem congenital disorder, presents with characteristic facial features, intellectual disability, persistent fetal fingertip pads, skeletal abnormalities, and postnatal growth delays. KS1 results from pathogenic variants in the KMT2D gene, which encodes a histone methyltransferase protein involved in chromatin remodeling, promoter and enhancer regulation, and scaffold formation during early development. KMT2D also mediates cell signaling pathways, responding to external stimuli and organizing effector protein assembly. Research on KMT2D's molecular mechanisms in KS1 has primarily focused on its histone methyltransferase activity, leaving a gap in understanding the methyltransferase-independent roles in KS1 clinical manifestations. METHODS: This scoping review examines KMT2D's role in gene expression regulation across various species, cell types, and contexts. We analyzed human pathogenic KMT2D variants using publicly available databases and compared them to research organism models of KS1. We also conducted a systematic search of healthcare and governmental databases for clinical trials, studies, and therapeutic approaches. RESULTS: Our review highlights KMT2D's critical roles beyond methyltransferase activity in diverse cellular contexts and conditions. We identified six distinct groups of KMT2D as a cell signaling mediator, including evidence of methyltransferase-dependent and -independent activity. A comprehensive search of the literature, clinical databases, and public registries emphasizes the need for basic research on KMT2D's functional complexity and longitudinal studies of KS1 patients to establish objective outcome measurements for therapeutic development. CONCLUSION: We discuss how KMT2D's role in translating external cellular communication can partly explain the clinical heterogeneity observed in KS1 patients. Additionally, we summarize the current molecular diagnostic approaches and clinical trials targeting KS1. This review is a resource for patient advocacy groups, researchers, and physicians to support KS1 diagnosis and therapeutic development.