Ocular findings in a patient with oculofaciocardiodental (OFCD) syndrome and a novel BCOR pathogenic variant

Foveal photoreceptor atrophy, persistent fetal vasculature, congenital cataracts, and microphthalmia in a pediatric patient with BCOR-associated oculo-facio-cardio-dental (OFCD) syndrome

Purpose

To report a case of oculo-facio-cardio-dental (OFCD) syndrome secondary to a novel BCOR variant in a pediatric patient with congenital cataracts, microphthalmia, persistent fetal vasculature (PFV), focal chorioretinal hyperpigmentation, peripheral retinal avascularity, and foveal photoreceptor atrophy.

Observations

A 3-month-old female patient was referred for bilateral congenital cataracts with microphthalmia. Her past medical history was significant for syndactyly of the toes, left bifid rib, atrial septal defect, patent ductus arteriosus, mitral regurgitation, pulmonary hypertension, anemia of prematurity, vesicoureteral reflux, and duodenal atresia. Examination under anesthesia revealed persistent fetal vasculature (PFV) with peripheral avascularity, foveal photoreceptor atrophy, and focal chorioretinal hyperpigmentation. A bilateral lensectomy with anterior vitrectomy and posterior capsulotomy were performed. Genetic testing identified a novel heterozygous pathogenic variant in the BCOR gene (c.1612C > T (p.Gln538Ter)), confirming a diagnosis of OFCD syndrome.

Conclusions and importance

This case describes novel posterior segment findings in a patient with OFCD. A detailed examination of both anterior and posterior segments in combination with multimodal imaging should be performed in patients suspected of having OFCD, as this may be critical in determining visual potential and appropriate surgical management.

Oculo-facio-cardio-dental (OFCD) syndrome: a case report

BACKGROUND

Oculo-facio-cardio-dental (OFCD) syndrome is a rare condition that affects the eyes, face, heart, and teeth of patients. One notable dental characteristic of OFCD is radiculomegaly, or root gigantism, which highlights the role of dentists in detecting this syndrome. OFCD is an X-linked dominant syndrome that results from a variant in the BCOR gene. Our study presents the first documented case of OFCD in Vietnam and reports a novel BCOR gene variant observed in this case.

CASE PRESENTATION

A 19-year-old Vietnamese female patient with an extremely long root with an abscess was clinically examined for the expression of OFCDs. The radiograph and the variant in BCOR gene were also evaluated. We identified abnormalities in the teeth, as well as ocular, facial, and cardiac features, with radiculomegaly of the canines being a specific symptom for OFCDs. The patient's genetic analysis revealed a pathogenic heterozygous deletion at intron 11 of the BCOR gene, representing a novel variant.

CONCLUSION

Oculo-facio-cardio-dental syndrome (OFCD) is an extremely rare condition characterized by abnormalities in the eyes, face, heart, and teeth, often caused by variants in the BCOR gene. Radiculomegaly, or enlarged dental roots, is a key diagnostic feature of OFCD, and early detection is crucial for preventing future dental complications.

Ocular severe involvement in oculofaciocardiodental syndrome: Description of a case series

BACKGROUND

Oculofaciocardiodental (OFCD) syndrome is a rare genetic disorder affecting ocular, facial, dental, and cardiac systems, being an X-linked condition caused by pathogenic variants in the BCL-6 corepressor gene (BCOR). We report a case series of three female patients with OFCD syndrome with severe glaucoma.

RESULTS

Three female patients with OFCD syndrome with different variants involving BCOR gene, in heterozygosity: a seven-years-old girl with an insertion (c.2037_2038dupCT), a nine years-old girl with a microdeletion in the X (p21.2-p11.4)) spanning the BCOR gene; and a 25 years-old female with a deletion (c.3858_3859del). Systemic involvement is variable among patients ranging from one patient mainly with ocular and dental involvement to one with associated intra-auricular and intra-ventricular defects. All the patients presented with congenital cataracts diagnosed in the first days of life. Cataract surgery was performed without incidents between 6 and 16 weeks of age in all the patients. Postoperatively, the three patients developed ocular hypertension and glaucoma with the need for surgical interventions, including trabeculectomy, Ahmed valve implantation, and cyclophotocoagulation.

CONCLUSION

OFCD syndrome characterizes by a severe ocular involvement with glaucoma as a characteristic feature. Ocular hypertension after cataract surgery in these patients is challenging, almost always needing surgery during childhood. Therefore, we consider BCOR disruption may predispose to a higher incidence of glaucoma due to its aggressiveness and early onset on our case series. The awareness of these complications is crucial to an adequate follow-up of the patients.

A rare genotype of biallelic mosaic variants in BCOR gene causing a bilateral ocular anterior segment dysgenesis and cataracts

Oculofaciocardiodental (OFCD) syndrome is a rare X-linked dominant syndrome characterized by the involvement of the eyes, face, teeth, and heart with variable expressivity. The syndrome is caused by loss-of-function variants in the BCOR gene located on the X chromosome. OFCD affects only females with presumed embryonic lethality among males. We report a first case of a female with biallelic mosaic variants in BCOR gene, leading to a severe ocular phenotype including anterior segment dysgenesis, cataracts, and retinal involvement. The unique condition of biallelic mosaic loss-of-function mutations leads to a variable expression of an allele with the pathogenic variant, independent of the X-Inactivation pattern. This novel mechanism of co-existent biallelic mosaicism should be suspected in unexplained severe cases of OFCD.

A novel deletion mutation in the BCOR gene is associated with oculo-facio-cardio-dental syndrome: a case report

Background

Oculo-facio-cardio-dental syndrome is a rare X-linked dominant syndrome, characterized by radiculomegaly, congenital cataracts, dysmorphic facial features, and congenital heart disease. Because of the rarity, this syndrome could be misdiagnosed by the clinician, especially for the infant who may present only one to two systems involved.

Case presentation

Here we report a 3-month-old female infant presenting with typical clinical manifestations of oculo-facio-cardio-dental syndrome, like ocular, facial, cardiac, and skeletal abnormalities, and the genetic analyses of the proband and her parents were provided. Genetic evaluations were completed using whole exon sequencing, which revealed a novel heterozygous mutation between exons 7 and 14 of the BCOR gene(OMIM:300485) in this patient but not in her parents. This mutation is likely to encode a premature stop codon producing a truncated protein. Our patient was diagnosed early enough to allow for the cardiac defects to be treated first, and she will be closely followed up to ensure that any new presentations are treated in a timeous manner.

Conclusion

This patient fits the diagnostic criteria for oculo-facio-cardio-dental syndrome and is the youngest oculo-facio-cardio-dental syndrome patient ever reported, which is most important for her prognosis. In addition, this manuscript also describes a novel potenitally causative mutation for this syndrome.

Down syndrome with bilateral posterior lenticonus

We present a case of bilateral posterior lenticonus in a young boy with Down syndrome. Association of posterior lenticonus in Down syndrome is rarely reported in the literature. We have discussed the clinical features and management of this patient at our hospital.

Co-occurrence of orofacial clefts and clubfoot phenotypes in a sub-Saharan African cohort: Whole-exome sequencing implicates multiple syndromes and genes

Background

Orofacial clefts (OFCs) are congenital malformations of the face and palate, with an incidence of 1 per 700 live births. Clubfoot or congenital talipes equinovarus (CTEV) is a three‐dimensional abnormality of the leg, ankle, and feet that leads to the anomalous positioning of foot and ankle joints and has an incidence of 1 per 1000 live births. OFCs and CTEV may occur together or separately in certain genetic syndromes in addition to other congenital abnormalities. Here, we sought to decipher the genetic etiology of OFC and CTEV that occurred together in six probands.

Methods

At the time of recruitment, the most clinically obvious congenital anomalies in these individuals were the OFC and CTEV. We carried out whole‐exome sequencing (WES) on DNA samples from probands and available parents employing the Agilent SureSelect XT kit and Illumina HiSeq2500 platform, followed by bioinformatics analyses. WES variants were validated by clinical Sanger Sequencing.

Results

Of the six probands, we observed probable pathogenic genetic variants in four. In three probands with probable pathogenic genetic variants, each individual had variants in three different genes, whereas one proband had probable pathogenic variant in just one gene. In one proband, we observed variants in DIS3L2, a gene associated with Perlman syndrome. A second proband had variants in EPG5 (associated with Vici Syndrome), BARX1 and MKI67, while another proband had potentially etiologic variants in FRAS1 (associated with Fraser Syndrome 1), TCOF1 (associated with Treacher Collins Syndrome 1) and MKI67. The last proband had variants in FRAS1, PRDM16 (associated with Cardiomyopathy, dilated, 1LL/Left ventricular noncompaction 8) and CHD7 (associated with CHARGE syndrome/Hypogonadotropic hypogonadism 5 with or without anosmia).

Conclusion

Our results suggest that clubfoot and OFCs are two congenital abnormalities that can co‐occur in certain individuals with varying genetic causes and expressivity, warranting the need for deep phenotyping.

Molecular Changes in Retinoblastoma beyond RB1: Findings from Next-Generation Sequencing

Simple Summary

The gene causing retinoblastoma was the first tumor suppressor cloned (1986) and because retinoblastoma is the classic example of autosomal dominant inheritance, there has been little research on non-RB1 alterations in tumors and the impact these alterations have on growth patterns in the eye, metastases and predilection for non-ocular cancers. This study interrogated enucleated retinoblastoma specimens using a MSK-IMPACT clinical next-generation sequencing panel with the aim to correlate them with clinicopathologic characteristics. We found that vitreous seeding (the main reason for eye removal) correlates with copy number variations, specifically 1q gains and 16q loss. We also found that somatic BCOR mutations correlate with propensity for metastasis and this offers a molecular pathway for monitoring high risk tumors. In addition, the finding that 11% of these retinoblastoma patients have additional germline mutations (on other chromosomes) that predispose them to a different host of cancers throughout their lives enables more targeted and specific screening strategies.

Abstract

This investigation uses hybridization capture-based next-generation sequencing to deepen our understanding of genetics that underlie retinoblastoma. Eighty-three enucleated retinoblastoma specimens were evaluated using a MSK-IMPACT clinical next-generation sequencing panel to evaluate both somatic and germline alterations. Somatic copy number variations (CNVs) were also identified. Genetic profiles were correlated to clinicopathologic characteristics. RB1 inactivation was found in 79 (97.5%) patients. All specimens had additional molecular alterations. The most common non-RB1 gene alteration was BCOR in 19 (22.9%). Five (11.0%) had pathogenic germline mutations in other non-RB1 cancer predisposition genes. Significant clinicopathologic correlations included: vitreous seeds associated with 1q gains and 16q loss of heterozygosity (BH-corrected p-value = 0.008, 0.004; OR = 12.6, 26.7, respectively). BCOR mutations were associated with poor prognosis, specifically metastases-free survival (MFS) (nominal p-value 0.03). Furthermore, retinoblastoma patients can have non-RB1 germline mutations in other cancer-associated genes. No two specimens had the identical genetic profile, emphasizing the individuality of tumors with the same clinical diagnosis.

OFCD syndrome and extraembryonic defects are revealed by conditional mutation of the Polycomb-group repressive complex 1.1 (PRC1.1) gene BCOR

BCOR is a critical regulator of human development. Heterozygous mutations of BCOR in females cause the X-linked developmental disorder Oculofaciocardiodental syndrome (OFCD), and hemizygous mutations of BCOR in males cause gestational lethality. BCOR associates with Polycomb group proteins to form one subfamily of the diverse Polycomb repressive complex 1 (PRC1) complexes, designated PRC1.1. Currently there is limited understanding of differing developmental roles of the various PRC1 complexes. We therefore generated a conditional exon 9-10 knockout Bcor allele and a transgenic conditional Bcor expression allele and used these to define multiple roles of Bcor, and by implication PRC1.1, in mouse development. Females heterozygous for Bcor exhibiting mosaic expression due to the X-linkage of the gene showed reduced postnatal viability and had OFCD-like defects. By contrast, Bcor hemizygosity in the entire male embryo resulted in embryonic lethality by E9.5. We further dissected the roles of Bcor, focusing on some of the tissues affected in OFCD through use of cell type specific Cre alleles. Mutation of Bcor in neural crest cells caused cleft palate, shortening of the mandible and tympanic bone, ectopic salivary glands and abnormal tongue musculature. We found that defects in the mandibular region, rather than in the palate itself, led to palatal clefting. Mutation of Bcor in hindlimb progenitor cells of the lateral mesoderm resulted in 2/3 syndactyly. Mutation of Bcor in Isl1-expressing lineages that contribute to the heart caused defects including persistent truncus arteriosus, ventricular septal defect and fetal lethality. Mutation of Bcor in extraembryonic lineages resulted in placental defects and midgestation lethality. Ubiquitous over expression of transgenic Bcor isoform A during development resulted in embryonic defects and midgestation lethality. The defects we have found in Bcor mutants provide insights into the etiology of the OFCD syndrome and how BCOR-containing PRC1 complexes function in development.

Recent developments in the management of congenital cataract

Congenital cataract is a rare eye disease, one of the leading treatable causes of low vision in children worldwide. Hereditary cataracts can be divided in syndromic and non-syndromic cataracts. Early diagnosis in congenital cataracts is key to reach good visual function. Current surgical techniques, that combine microincision cataract extraction and primary intraocular lens (IOL) implantation, have improved childhood cataract outcome. Complications include posterior capsule opacification (PCO), aphakic or pseudophakic glaucoma, uveitis, pupil displacement and IOL decentration. A recent study using a modified Delphi approach identified areas of consensus and disagreement in the management of pediatric cataract. A consensus or near consensus was achieved for 79% of the questions, however 21% of the questions remained controversial, as for IOL implantation strategy. Congenital cataracts show a highly variable phenotype and genotype, and can be related to different mutations, genetic variance, and other risk factors. Congenital cataracts can be associated with other ocular developmental abnormalities, including microphthalmia, microcornea, or aniridia and with systemic findings. Next-generation sequencing (NGS) and forthcoming new ultra-high-throughput sequencing represent excellent tools to investigate the genetic causes of congenital cataracts. A better recognition of different clinical presentations and underlying etiologies of congenital cataracts may lead to the development of new approaches to improve visual outcome after cataract surgery and promote early detection of systemic associated syndromes.

Two Cases of Oculofaciocardiodental (OFCD) Syndrome due to X-Linked BCOR Mutations Presenting with Infantile Hemangiomas: Phenotypic Overlap with PHACE Syndrome

Background

Oculofaciocardiodental (OFCD) syndrome is due to mutations in BCOR (BCL-6 corepressor). OFCD has phenotypic overlaps with PHACE syndrome (Posterior fossa anomalies, Hemangioma, Arterial anomalies, Cardiac defects, Eye anomalies). Infantile hemangiomas are a key diagnostic criterion for PHACE, but not for OFCD. A previous study reported two cases of infantile hemangiomas in OFCD, but the authors could not exclude chance association.

Case Presentation

We describe two novel cases of female patients (one initially diagnosed with PHACE syndrome), both of whom had infantile hemangiomas. Ophthalmological findings were consistent with oculofaciocardiodental (OFCD) syndrome. Upon genetic testing, these two females were determined to have X-linked BCOR mutations confirming OFCD syndrome diagnoses.

Conclusion

These case reports add support to the hypothesis that infantile hemangiomas may be a feature of OFCD. BCOR may potentially be within a pathway of genes involved in PHACE syndrome and/or in infantile hemangioma formation.

Genetic landscape of isolated pediatric cataracts: extreme heterogeneity and variable inheritance patterns within genes

Pediatric cataract represents an important cause of pediatric visual impairment. While both genetic and environmental causes for pediatric cataract are known, a large proportion remains idiopathic. The purpose of this review is to discuss genes involved in isolated pediatric cataract, with a focus on variable inheritance patterns within genes. Mutations in over 52 genes are known to cause isolated pediatric cataract, with a major contribution from genes encoding for crystallins, transcription factors, membrane proteins, and cytoskeletal proteins. Interestingly, both dominant and recessive inheritance patterns have been reported for mutations in 13 different cataract genes. For some genes, dominant and recessive alleles represent distinct types of mutations, but for many, especially missense variants, there are no clear patterns to distinguish between dominant and recessive alleles. Further research into the functional effects of these mutations, as well as additional data on the frequency of the identified variants, is needed to clarify variant pathogenicity. Exome sequencing continues to be successful in identifying novel genes associated with congenital cataract but is hindered by the extreme genetic heterogeneity of this condition. The large number of idiopathic cases suggests that more genes and potentially novel mechanisms of gene disruption remain to be identified.

Expanding the phenotype of the X-linked BCOR microphthalmia syndromes

Two distinct syndromes arise from pathogenic variants in the X-linked gene BCOR (BCL-6 corepressor): oculofaciocardiodental (OFCD) syndrome, which affects females, and a severe microphthalmia ('Lenz'-type) syndrome affecting males. OFCD is an X-linked dominant syndrome caused by a variety of BCOR null mutations. As it manifests only in females, it is presumed to be lethal in males. The severe male X-linked recessive microphthalmia syndrome ('Lenz') usually includes developmental delay in addition to the eye findings and is caused by hypomorphic BCOR variants, mainly by a specific missense variant c.254C > T, p.(Pro85Leu). Here, we detail 16 new cases (11 females with 4 additional, genetically confirmed, affected female relatives; 5 male cases each with unaffected carrier mothers). We describe new variants and broaden the phenotypic description for OFCD to include neuropathy, muscle hypotonia, pituitary underdevelopment, brain atrophy, lipoma and the first description of childhood lymphoma in an OFCD case. Our male X-linked recessive cases show significant new phenotypes: developmental delay (without eye anomalies) in two affected half-brothers with a novel BCOR variant, and one male with high myopia, megalophthalmos, posterior embryotoxon, developmental delay, and heart and bony anomalies with a previously undescribed BCOR splice site variant. Our female OFCD cases and their affected female relatives showed variable features, but consistently had early onset cataracts. We show that a mosaic carrier mother manifested early cataract and dental anomalies. All female carriers of the male X-linked recessive cases for whom genetic confirmation was available showed skewed X-inactivation and were unaffected. In view of the extended phenotype, we suggest a new term of X-linked BCOR-related syndrome.