Duane's retraction syndrome associated with chromosome 4q27-31 segment deletion

Chromosomal microarray analysis of patients with Duane retraction syndrome

PURPOSE

Duane retraction syndrome (DS) is a rare congenital strabismus with genetic heterogeneity. The genetic causes of DS are not always of monogenic origin; various chromosomal copy number variations (CNVs) have also been reported. The objective of our study was to characterize the CNVs, including gains and losses detected by high-resolution chromosomal microarray in patients with DS.

METHODS

Twenty patients with DS were investigated using high-resolution chromosomal microarray analysis (CMA) (Affymetrix CytoScan Array 750 K). Conventional cytogenetic analysis was also performed.

RESULTS

All samples revealed normal karyotype by cytogenetic analysis. However, in all our patients, multiple CNVs, including gains and losses, were detected using the high-resolution CMA method. Chromosomal loci 1q21.2, 2p11.2-q11.1, 2q21.1-q21.2, 4p16.1, 7p11.2-q11.21, 14q32.33, 17p11.2-q11.1 and 20p11.1-q11.21 were the most frequently affected regions.

CONCLUSIONS

This study emphasized that CNVs in several chromosomal regions are known to be involved in DS. We also underscore the genetic heterogeneity of DS. Our suggestion is that genes located in the most frequently affected regions should be focused on in the following candidate gene studies.

CHN1 gene mutation analysis in patients with Duane retraction syndrome

PURPOSE

To investigate CHN1 (chimerin 1) gene mutations in patients with isolated nonsyndromic Duane syndrome and accompanying positive familial history, bilaterality, or various systemic disorders.

METHODS

Patients with Duane retraction syndrome (DRS) and a positive family history of congenital ocular motility disturbance or bilateral involvement or accompanying any congenital disorder(s) seen consecutively at a single center from 2013 to 2016 were enrolled. All subjects underwent full ophthalmologic examination, including refraction, best-corrected visual acuity, ocular alignment and motility, globe retraction, and biomicroscopic or fundus evaluation. DNA samples were investigated by direct sequencing of the coding regions of the CHN1 gene.

RESULTS

A total of 30 patients (15 males) were included (mean age, 11.8 ± 10.4 years; range, 2-45 years): 8 cases presented with bilateral DRS; 22, with unilateral DRS. Family history of ocular motility abnormality was positive in 16 patients. Eleven cases had an additional congenital disorder. In 2 patients, 2 different mutations were detected in the CHN1 gene: p.E313K (c.937G>A) and p.N224S (c.671A>G).

CONCLUSIONS

CHN1 mutations were identified in 2 bilateral cases and in 1 parent of 1 affected case. One mutation is novel and occurred with additional vertical gaze abnormalities. Additional genetic studies evaluating chimerin 1 (CHN1) and its role in the development of the ocular motor axis are needed to provide new data about these mutations and phenotypic variations.

CCDD Phenotype Associated with a Small Chromosome 2 Deletion

PURPOSE

Some individuals are born with congenital limitation of ocular motility, often associated with ptosis and retraction of the globe. Many of these disorders are now known as the congenital cranial dysinnervation disorders (CCDDs). While several genes have been associated with CCDD phenotypes, there are still patients for whom the genetic basis has not been identified.

METHODS

Clinical evaluation and neuroimaging, sequencing of candidate genes, and array comparative genomic hybridization (array CGH).

RESULTS

The patient was a four-year-old girl with mild dysmorphism; bilateral mild ptosis; substantial limitation of abduction OS with milder limitations of abduction OD, adduction OS, and vertical gaze OS; and retraction OS > OD on attempted adduction. No mutations were detected in the HOXA1, KIF21A, SALL4, TUBB3, and CHN1 genes. Array CGH revealed a 8 Kb de novo deletion on chromosome 2 (2q24.3) that encompassed a portion of only one gene, the Xin Actin-binding Repeat containing 2 (Gene Symbol XIRP2; NM_001079810). This gene encodes a protein that is involved in muscle development and protecting actin filaments from depolymerization. It interacts functionally with 10 other proteins playing a similar role in muscle development.

CONCLUSIONS

This patient's chromosomal abnormality affected only one gene that currently seems involved only in muscle development. All other genes currently associated with the CCDDs affect neurologic development. Genetic information from this patient implies that genes involved in development and maintenance of extraocular muscles can cause congenital ocular motility disorders as well.

Partial duplication of chromosome 19 associated with syndromic duane retraction syndrome

BACKGROUND

To evaluate possible monogenic and chromosomal anomalies in a patient with unilateral Duane retraction syndrome, modest dysmorphism, cerebral white matter abnormalities, and normal cognitive function.

MATERIALS AND METHODS

Performing high-resolution array comparative genomic hybridization (array CGH) and sequencing of HOXA1, KIF21A, SALL4, and CHN1 genes.

RESULTS

The proband had unilateral Duane retraction syndrome (DRS) type III on the right with low-set ears, prominent forehead, clinodactyly, and a history of frequent infections during early childhood. Motor development and cognitive function were normal. Parents were not related, and no other family member was similarly affected. MRI revealed multiple small areas of high signal on T2 weighted images in cerebral white matter oriented along white matter tracts. Sequencing of HOXA1, KIF21A, SALL4, and CHN1 did not reveal any mutation(s). Array CGH showed a 95 Kb de novo duplication on chromosome 19q13.4 encompassing four killer cell immunoglobulin-like receptor (KIR) genes. Conclusions. KIR genes have not previously been linked to a developmental syndrome, although they are known to be expressed in the human brain and brainstem and to be associated with certain infections and autoimmune diseases, including some affecting the nervous system. DRS and brain neuroimaging abnormalities may imply a central and peripheral oligodendrocyte abnormality related in some fashion to an immunomodulatory disturbance.

Multigeneration family with short stature, developmental delay, and dysmorphic features due to 4q27-q28.1 microdeletion

Deletions of the long arm of chromosome 4 are rare but have been previously reported to be associated with craniofacial anomalies, digital anomalies, developmental delay, growth failure, and cardiovascular anomalies. Strehle et al. previously presented 20 patients with 4q deletions and began to construct a phenotype-genotype map for chromosome 4q. This report follows up on that work by providing clinical and molecular cytogenetic data on a three generation pedigree including seven patients with short stature, dysmorphic features, and developmental delay identified to have a 4q27-q28.1 microdeletion of approximately 5.68 Mb by oligonucleotide chromosomal microarray. This family represents a rare report of an inherited interstitial deletion of the long arm of chromosome 4. To our knowledge, only two cases have been previously reported. The contribution of candidate genes in the region is discussed.

Duane syndrome in association with 48,XXYY karyotype

Duane syndrome is an ocular motility disorder consisting of deficient horizontal eye movements, eyelid retraction, palpebral fissure narrowing, and abnormal vertical eye movements. It occurs in 1%-5% of patients with strabismus and has also been reported in several syndromes and chromosome abnormalities. Although most cases are sporadic, autosomal-dominant inheritance is seen in up to 10% of cases. Recently, Duane syndrome has been reported to occur in the setting of chromosomal duplication. The 48,XXYY syndrome is a rare syndrome involving duplication of the sex chromosomes. Ocular abnormalities are not typical of this condition. We report the first case of Duane syndrome presenting in an 8-month-old boy with XXYY syndrome. This case lends further support to the association of chromosomal duplication and Duane syndrome.

Duane syndrome in the setting of chromosomal duplications

PURPOSE

To describe the clinical findings in 3 patients with Duane syndrome and 3 different chromosomal duplications that may indicate the location of genes involved in the pathogenesis of this ocular motility disorder.

DESIGN

Observational case series.

METHODS

setting: Clinical practice. patient or study population: Three patients with Duane syndrome and chromosomal duplications from the clinical practice of 1 of the authors. observation procedures: Chart review and retrieval of clinical data and results of pertinent clinical tests, in this case chromosomal studies. main outcome measure: Reporting of details of clinical findings and duplicated chromosomal regions.

RESULTS

Two patients had unilateral type I Duane syndrome and 1 had bilateral type I Duane syndrome. Two had cognitive delay, and all 3 had other systemic abnormalities, including a variety of congenital malformations. The chromosomal abnormalities that were detected using microarray analysis were 2q13(RP11-20G1,RP11-461N11) × 3, 10q24.2q26.3(101,532,585-135,284, 169) × 3, 20q13.12(44,796,613-44,945, 818) × 3, and 22q11.1q11.22(RP11-701M12, RP11-71G19) × 3.

CONCLUSIONS

Patients with Duane syndrome and associated congenital malformations or developmental delay should be evaluated for the presence of underlying chromosomal duplications. The regions of chromosomes 2, 10, and 22 that we report may harbor genes involved in the pathogenesis of Duane syndrome.

Bilateral Duane retraction syndrome associated with an extraordinary hand anomaly

Duane retraction syndrome is an ocular motility disorder with which an increasing number of congenital abnormalities appear to be associated. In the present paper the authors report a case of bilateral Duane retraction syndrome with an extraordinary hand abnormality. Numerous theories concerning the etiology and pathogenesis of Duane retraction syndrome and its relationship to the associated findings have been proposed, but the exact mechanism is still under investigation. Further multi-centered studies and the classification of the associated clinical findings in an organized manner may help to explain this mechanism.

Midline orofacial cleft defects in association with type 1 Duane's retraction syndrome

Anomalies of ocular motility associated with Duane's retraction syndrome (DRS) have often been perceived as isolated phenomena arising as a result of congenital ocular miswiring between the lateral and medial recti muscles. Interestingly, the reporting of concomitant ocular and systemic anomalies arising in the setting of DRS discounts this narrow perception and highlights the importance of a thorough investigation for non-ocular comorbidities. A 37-year-old Caucasian male presented for a routine ocular examination with complaints of gradual reduction in uncorrected near vision. Our testing confirmed the characteristic deficit of abduction, palpebral fissure narrowing and globe retraction consistent with a type 1 Duane's defect of the right eye. A midline cleft lip and palate were also noted in the absence of signs of nuchal rigidity/reduced range of motion in the cervical spine, spinal misalignment, deafness, optic nerve anomalies, hypertelorism or altered mental state. Awareness of key comorbidities and the importance of thorough clinical evaluation with appropriate supplemental testing and consultation with a paediatric ophthalmologist are warranted in non-isolated presentations of DRS.

The genetics of strabismus

Strabismus (misalignment of the eyes; also known as "squint") comprises a common heterogeneous group of disorders characterised by a constant or intermittent ocular deviation often associated with amblyopia (uniocular failure of normal visual development) and reduced or absent binocular vision. The associated poor cosmetic appearance may also interfere with social and psychological development. Extensive twin and family studies suggest a significant genetic component to the aetiology of strabismus. The complexity of the molecular basis of strabismus is now beginning to be elucidated with the identification of genetic loci and disease causing genes. Currently greater insights have been gained into the incomitant subtype (differing magnitude of ocular misalignment according to direction of gaze), whereas less is known about the pathogenesis of the more common childhood concomitant strabismus. It is hoped that a greater understanding of the molecular genetics of these disorders will lead to improved knowledge of disease mechanisms and ultimately to more effective treatment. The aim of this paper is to review current knowledge of the molecular genetics of both incomitant and concomitant strabismus.

A family with Duane anomaly and distal limb abnormalities: A further family with the arthrogryposis-ophthalmoplegia syndrome

A two-generation family is reported in which three members have Duane anomaly and distal limb abnormalities. All three affected have photopic electroretinogram responses that are abnormal or at the lower limit of the normal range with normal scotopic responses. Two affected family members also have hearing loss. The likeliest diagnosis is the syndrome listed as "arthrogryposis-ophthalmoplegia syndrome" on the London Dysmorphology Database or as "arthrogryposis with oculomotor limitation and electroretinal abnormalities" or "oculomelic aplasia" in OMIM [MIM 108145]. In view of the similarities with Okihiro syndrome, a search for mutations within the SALL4 gene was undertaken, but none were identified.

Familial ptotic lid elevation during ipsilateral abduction

PURPOSE

To report and discuss the clinical findings of a 17-member family with 2 siblings who exhibit ptosis and abnormal synkinetic lid elevation associated with ipsilateral abduction.

SUBJECTS AND METHODS

Sixteen members of the 17-member immediate family underwent ophthalmic examination.

RESULTS

Two siblings exhibited ptosis and abnormal synkinetic lid elevation associated with ipsilateral abduction. One was bilaterally affected and the other had unilateral findings. A third sibling had isolated bilateral congenital ptosis. A fourth demonstrated classic Duane syndrome Type I in the right eye. Other family members did not have ophthalmic abnormalities.

CONCLUSIONS

A unifying mechanism of congenital cranial dysinnervation may underlie these and similar phenotypes of oculomotor and/or abducens nerve abnormalities with or without abnormal synkinesis.

Paradoxical eyelid movement in trisomy 2p

Paradoxical eyelid movement was reported in a 12-year-old female with 46,XX,dup(2)(p25.3p22.2). Alternating seesaw-like movement of the eyelids during lateral gazing had been observed at 5 months of age when she was first referred to our neuropediatric outpatient department, and the abnormal lid movement persisted without any change for 11 years. The differentiation of the features of the paradoxical lid movements in our patient from those of Duane syndrome were discussed, and a possible pathogenesis is discussed as well. Besides ophthalmologic abnormalities, the patient demonstrated severe psychomotor retardation, marked growth failure, symptomatic generalized epilepsy, and multiple anomalies. The dysmorphism consisted of a cleft lip, a narrow high-arched palate, malalignment, lowset ears, and kyphoscoliosis caused by fused thoracic vertebrae.

Duane's syndrome

Duane's syndrome is an unusual congenital form of strabismus where there is paradoxical anomalous lateral rectus innervation of the affected eye due to misdirection of axons destined for the medial rectus. Three types of Duane's syndrome are recognized. Most cases of Duane's syndrome are sporadic but up to 10% are familial, usually with autosomal dominant inheritance. Several autosomal dominant syndromes with dysmorphic features are associated with Duane's syndrome. Chromosomal loci for genes contributing to Duane's syndrome have been suggested at 4q, 8q and 22q. Duane's syndrome is heterogeneous at multiple levels with variations in its ocular manifestations, accompanying systemic manifestations and in the chromosomal loci with which it may be associated. The definition clinically and genetically of the various subgroups of Duane's syndrome will provide a valuable insight into brainstem axonal guidance to the extraocular muscles during human development.

Clinical diversity of hereditary Duane's retraction syndrome

OBJECTIVE

To define the spectrum of ophthalmic manifestations of Duane's retraction syndrome (DRS) in a large family.

DESIGN

Cross-sectional study of 110 among 114 living relatives in an extended family.

METHODS

History and ophthalmic examination obtained on all participants.

MAIN OUTCOME MEASURES

Ocular motility, strabismus, visual acuity, binocularity, associated neurologic problems.

RESULTS

Twenty-five individuals were affected with DRS. Twenty-four subjects (96%) had bilateral DRS, but there was a broad spectrum of severity. Strabismus occurred in 76% and amblyopia in 48%. Associated findings included fourth cranial nerve palsy, partial third cranial nerve palsy, nystagmus, seizures, and deafness. Fourth cranial nerve palsies and manifest strabismus tended to cluster within single family units.

CONCLUSIONS

Strabismus and amblyopia are much more common with bilateral DRS than with unilateral DRS. There is much phenotypic variability among individuals within families with hereditary Duane's syndrome. The responsible gene(s) may affect the development of many cranial nerves. Genetic compounding may play a role in the phenotypic segregation seen within this large family.

Localization of a gene for Duane retraction syndrome to chromosome 2q31

Duane retraction syndrome (DRS) is a congenital eye-movement disorder characterized by a failure of cranial nerve VI (the abducens nerve) to develop normally, resulting in restriction or absence of abduction, restricted adduction, and narrowing of the palpebral fissure and retraction of the globe on attempted adduction. DRS has a prevalence of approximately 0.1% in the general population and accounts for 5% of all strabismus cases. Undiagnosed DRS in children can lead to amblyopia, a permanent uncorrectable loss of vision. A large family with autosomal dominant DRS was examined and tested for genetic linkage. After exclusion of candidate regions previously associated with DRS, a genomewide search with highly polymorphic microsatellite markers was performed, and significant evidence for linkage was obtained at chromosome 2q31 (D2S2314 maximum LOD score 11.73 at maximum recombination fraction. 0). Haplotype analysis places the affected gene in a 17.8-cM region between the markers D2S2330 and D2S364. No recombinants were seen with markers between these two loci. The linked region contains the homeobox D gene cluster. Three of the genes within this cluster, known to participate in hindbrain development, were sequenced in affected and control individuals. Coding sequences for these genes were normal or had genetic alterations unlikely to be responsible for the DRS phenotype. Identifying the gene responsible for DRS may lead to an improved understanding of early cranial-nerve development.

Exclusion of candidate genetic loci for Duane retraction syndrome

PURPOSE

To report preliminary linkage analysis of a large Hispanic family showing autosomal dominant inheritance for Duane retraction syndrome.

METHODS

Microsatellite analysis was used to examine genomic DNA isolated from members of a large family with autosomal dominant Duane retraction syndrome for linkage to candidate loci for Duane retraction syndrome. Chromosomes 4, 8, and 22 were chosen for study because previous reports had documented karyotypic abnormalities in unrelated patients with Duane retraction syndrome.

RESULTS

No lod scores over 0.5 were found for markers on chromosomes 4, 8, or 22. This analysis excludes these candidate sites.

CONCLUSIONS

Studies do not support linkage between Duane retraction syndrome in this family and chromosomes 4, 8, and 22. Duane retraction syndrome may result from mutations in a heterogeneous group of genes.