Duplication 8q12: confirmation of a novel recognizable phenotype with duane retraction syndrome and developmental delay

Choice of refractive surgery types for myopia assisted by machine learning based on doctors' surgical selection data

In recent years, corneal refractive surgery has been widely used in clinics as an effective means to restore vision and improve the quality of life. When choosing myopia-refractive surgery, it is necessary to comprehensively consider the differences in equipment and technology as well as the specificity of individual patients, which heavily depend on the experience of ophthalmologists. In our study, we took advantage of machine learning to learn about the experience of ophthalmologists in decision-making and assist them in the choice of corneal refractive surgery in a new case. Our study was based on the clinical data of 7,081 patients who underwent corneal refractive surgery between 2000 and 2017 at the Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences. Due to the long data period, there were data losses and errors in this dataset. First, we cleaned the data and deleted the samples of key data loss. Then, patients were divided into three groups according to the type of surgery, after which we used SMOTE technology to eliminate imbalance between groups. Six statistical machine learning models, including NBM, RF, AdaBoost, XGBoost, BP neural network, and DBN were selected, and a ten-fold cross-validation and grid search were used to determine the optimal hyperparameters for better performance. When tested on the dataset, the multi-class RF model showed the best performance, with agreement with ophthalmologist decisions as high as 0.8775 and Macro F1 as high as 0.8019. Furthermore, the results of the feature importance analysis based on the SHAP technique were consistent with an ophthalmologist's practical experience. Our research will assist ophthalmologists in choosing appropriate types of refractive surgery and will have beneficial clinical effects.

Ocular Motor Dysfunction Due to Brainstem Disorders

BACKGROUND

The brainstem contains numerous structures including afferent and efferent fibers that are involved in generation and control of eye movements.

EVIDENCE ACQUISITION

These structures give rise to distinct patterns of abnormal eye movements when damaged. Defining these ocular motor abnormalities allows a topographic diagnosis of a lesion within the brainstem.

RESULTS

Although diverse patterns of impaired eye movements may be observed in lesions of the brainstem, medullary lesions primarily cause various patterns of nystagmus and impaired vestibular eye movements without obvious ophthalmoplegia. By contrast, pontine ophthalmoplegia is characterized by abnormal eye movements in the horizontal plane, while midbrain lesions typically show vertical ophthalmoplegia in addition to pupillary and eyelid abnormalities.

CONCLUSIONS

Recognition of the patterns and characteristics of abnormal eye movements observed in brainstem lesions is important in understanding the roles of each neural structure and circuit in ocular motor control as well as in localizing the offending lesion.

Oculo-Auriculo-Fronto-Nasal Syndrome With Duane Retraction Syndrome and Dysplastic Bony Structure in the Midline of Nose

Oculo-auriculo-fronto-nasal syndrome (OAFNS) is a rare anomaly characterized by features overlapping those of frontonasal dysplasia (FND) and the oculo-auriculo-vertebral spectrum (OAVS). The FND features malformation of frontonasal process-derived structures, characterized by anomalies in the central portion of the face. The OAVS is characterized by developmental anomalies of the first and second pharyngeal arches. The OAFNS is a condition with clinical features of both FND and OAVS.Here, the authors present the case of a male with OAFNS who not only exhibited typical OAFNS symptoms but also a dysplastic bony structure that bridged the anterior nasal spine and inferior nasal bones, and unilateral type 3 Duane retraction syndrome (absence of right-eye abduction). Abnormal nasal bones are characteristic of OAFNS; such abnormalities are absent from FND and OAVS. The authors reduced the dysplastic nasal bony structure via open external rhinoplasty, followed by lateral nasal osteotomy when he was 16 years of age. The nasal dorsum appeared natural after surgery and he was satisfied with the result.

A family study of complex chromosome rearrangement involving chromosomes 1, 8, and 11 and its reproductive consequences

Complex chromosome translocations are structural chromosomal rearrangements involving three or more chromosomes and more than two breakpoints. A complex chromosome rearrangement was detected in a phenotypically normal female patient that was referred to the hospital for genetic counseling due to reproductive failure. A cytogenetic evaluation was performed, according to standard method of chromosomal analysis, using G-banding technique. The patient's karyotype showed a balanced complex chromosome rearrangement (BCCR) involving chromosomes 1, 8, and 11 with three breakpoints 1p31, 8q13, and 11q23. The karyotype designed according to ISCN (2013), is 46,XX,t(1;8;11)(p31;q13;q23) (8qter→8q13::1p31→1qter;8pter→8q13::11q23→11qter;11pter→11q23::1p31→1pter). Additionally, the proband's mother and brother were tested, resulting in the same exact translocation. In this study, we describe all possible meiotic segregations regarding this translocation, as well as the clinical phenotypes which could arise, if unbalanced products of conception survive. This is a rare case of familial complex chromosome rearrangement, giving a view for its reproductive consequences.

What's new for us in strabismus?

Strabismus is one of the most challenging subspecialties encountered in the field of ophthalmology. The concept of etiology of strabismus is being advanced with the development of newer imaging modalities and increased understanding of the genetics of strabismus. Imaging is also being used to aid in the planning of strabismus surgery. Newer horizons are being explored in the amblyopia management. The good old eye-pad is being replaced with the iPad. Early detection of loss of stereopsis is being used to decide the timing for strabismus surgery. Improvement of binocular summation has been discovered as a benefit of corrective strabismus surgery. Newer surgical techniques such as new transposition procedures are being developed to correct complex strabismus. Strabismus surgeries aided by adjustable sutures have increased the precision of a strabismologist. A new light has been thrown on the psychosocial impact of strabismus. A present-day strabismologist has advanced from the goal of ocular alignment to a bigger perspective "to regain the paradise lost: stereopsis."

Retrospective karyotype study in mentally retarded patients

OBJECTIVE

To describe the chromosomal alterations in patients with mental retardation (MR) using G-banding karyotype analysis.

METHOD

A retrospective study of the results G-banding karyotype analysis of 369 patients investigated for MR was performed. Based on the structural rearrangements found, the authors searched all chromosomal regions related with breakpoints, and these were compared with the literature on MR and databases.

RESULTS

338 (91.6%) normal cases, and 31 (8.4%) with some type of chromosomal abnormality were identified. Among the altered cases, 21 patients (67.8%) were identified with structural chromosomal alterations, nine (29%) with numerical alterations, and one (3.2%) with numerical and structural alterations.

CONCLUSION

Structural chromosomal abnormalities were observed more frequently in this study. G-banding karyotyping contributes to the investigation of the causes of MR, showing that this technique can be useful for initial screening of patients. However, higher resolution techniques such as array based comparative genomic hybridization (aCGH) and multiplex ligation-dependent probe amplification (MPLA) can detect submicroscopic alterations commonly associated with MR.

CHARGE syndrome due to deletion of region upstream of CHD7 gene START codon

Background

CHARGE syndrome is an autosomal dominant disorder, characterized by ocular Coloboma, congenital Heart defects, choanal Atresia, Retardation, Genital anomalies and Ear anomalies. Over 90 % of typical CHARGE patients are mutated in the CHD7 gene, 65 %–70 % of the cases for all typical and suspected cases combined. The gene encoding for a protein involved in chromatin organization. The mutational spectrum include nonsense, frameshift, splice site, and missense mutations. Large deletions and genomic rearrangements are rare.

Case presentation

We report here on a 5.9 years old male of Moroccan origin displaying classic clinical features of CHARGE syndrome. Using CGH array and NGS analysis we detected a microdeletion (184 kb) involving the promoter region and exon 1 of CHD7 gene and the flanking RAB2 gene.

Conclusion

The present observation suggests that deletion limited to the regulatory region of CHD7 is sufficient to cause the full blown CHARGE phenotype. Different size of deletions can result in different phenotypes, ranging from a milder to severe CHARGE syndrome; this is based on a combination of major and minor diagnostic characteristics, therefore to a more variable clinical features, likely due to the additive effect of other genetic imbalances. MLPA and CGH techniques should be considered in the diagnostic protocol of individuals with a clinical suspect of CHARGE syndrome

The genetic basis of incomitant strabismus: consolidation of the current knowledge of the genetic foundations of disease

In recent years, our understanding of the genetic foundations of incomitant strabismus has grown significantly. Much new understanding has been gleaned since the concept of congenital cranial dysinnervation disorders (CCDDs) was introduced in 2002, and the genetic basis of CCDDs continues to be elucidated. In this review, we aim to provide an update of the genetic and clinical presentation of these disorders. Disorders reviewed include Duane syndrome (DS), HOXA1 and HOXB1 syndromes, Moebius syndrome, congenital fibrosis of the extraocular muscles (CFEOM), and horizontal gaze palsy with progressive scoliosis (HGPPS).

Strabismus genetics across a spectrum of eye misalignment disorders

Eye misalignment, called strabismus, is amongst the most common phenotypes observed, occurring in up to 5% of individuals in a studied population. While misalignment is frequently observed in rare complex syndromes, the majority of strabismus cases are non-syndromic. Over the past decade, genes and pathways associated with syndromic forms of strabismus have emerged, but the genes contributing to non-syndromic strabismus remain elusive. Genetic testing for strabismus risk may allow for earlier diagnosis and treatment, as well as decreased frequency of surgery. We review human and model organism literature describing non-syndromic strabismus, including family, twin, linkage, and gene expression studies. Recent advances in the genetics of Duane retraction syndrome are considered, as relatives of those impacted show elevated familial rates of non-syndromic strabismus. As whole genome sequencing efforts are advancing for the discovery of the elusive strabismus genes, this overview is intended to support the interpretation of the new findings.

8q12 microduplication including CHD7: clinical report on a new patient with Duane retraction syndrome type 3

Background

A novel multiple congenital anomalies syndrome has been recently identified in four patients carrying a 8q12 microduplication sharing the smallest region of overlap (SRO, size 1.6 Mb) including five genes CA8, ASPH, RAB2B, CLVS1 and CDH7. The phenotype is mainly characterized by neurodevelopmental delay, heart defects, facial features and Type 1 Duane anomaly. Increasing dosage of CDH7 was proposed to be responsible for the recurrent pattern of MCA.

Results

High resolution array-CGH analysis identified a 4.2 Mb de novo interstitial duplication of the 8q12.1-q12.3 chromosome region in a boy with developmental delay, dysmorphic features, type 3 Duane anomaly. This duplication includes several genes and spans the SRO.

Discussion

The present case represents a further patient with an interstitial duplication of chromosome 8q12 and several shared clinical features. Although more cases are needed to delineate the full-blown phenotype of 8q12 duplication syndrome, published data and present observations suggest that it results in a clinically recognizable phenotype. The presence of Duane anomaly in four out of five described patients with a 8q12 duplication definitely rules against the possibility of its being a chance finding unrelated to the imbalance and points toward a pathogenic role. Gene content analysis of the duplicated region and review of the literature suggest that gain-of-dosage of the CHD7 gene may be a good candidate for the main clinical features of the syndrome.

Complex cytogenetic rearrangements at the DURS1 locus in syndromic Duane retraction syndrome

Key Clinical Message

A patient with syndromic Duane retraction syndrome harbors a chromosome 811.1q13.2 inversion and 8p11.1-q12.3 marker chromosome containing subregions with differing mosaicism and allele frequencies. This case highlights the potential requirement for multiple genetic methods to gain insight into genotype–phenotype correlation, and ultimately into molecular mechanisms that underlie human disease.

8q12.1q12.3 de novo microdeletion involving the CHD7 gene in a patient without the major features of CHARGE syndrome: case report and critical review of the literature

CHARGE syndrome is an autosomal dominant inherited disorder characterized by a specific and recognizable pattern of anomalies. De novo mutations or deletions of the gene encoding chromodomain helicase DNA binding protein 7 (CHD7) are the major cause of CHARGE syndrome. In this report, we describe a patient with a typical phenotype characterized by psychomotor retardation, hypertrichosis, facial asymmetry, synophria, failure to thrive, developmental delay and gastro-esophageal reflux, carrying a de novo 6.04Mb interstitial deletion in 8q12.1q12.3 detected by single nucleotide polymorphism (SNP) array analysis. Despite the deletion includes CHD7 and although the patient shares some of the clinical features of the CHARGE syndrome, she does not fulfill the clinical criteria for this syndrome. To the best of our knowledge, this is the second case with an entire deletion of the CHD7 gene not leading to CHARGE syndrome and, for this reason, useful to expand and further delineate the clinical features associated with the 8q12.1q12.3 deletion. Furthermore, the literature review revealed that the phenotype secondary to duplications of the same region partially overlaps with the phenotype reported in this study. Selected genes that are present in the hemizygous state and which might be important for the phenotype of this patient, are discussed in context of the clinical features.

Duplication of 8q12 encompassing CHD7 is associated with a distinct phenotype but without duane anomaly

Interstitial duplications of 8q12 encompassing CHD7 have recently been described as a new microduplication syndrome. Three 8q12 duplications have been reported with shared recognizable phenotype: Duane anomaly, developmental delay and dysmorphic facial features. We identified a 2.7 Mb duplication on chromosome 8q12 with SNP-array in a patient with growth delay, congenital heart defects, ear anomalies and torticollis. To our knowledge, this is the smallest duplication reported to date. Our findings support the notion that increased copy number of CHD7 may underlie the phenotype of the 8q12 duplication. Our study together with previous studies suggest that the 8q12 duplication could be defined as a novel syndrome.