Neural misdirection in congenital ocular fibrosis syndrome: implications and pathogenesis

Variant types of Duane retraction syndrome: synergistic divergences and convergences

PURPOSE

To present the clinical features of 4 patients with Duane retraction syndrome characterized by synergistic divergence or convergence, abnormal vertical movements, and accessory fibrotic bands.

METHODS

The medical records of 4 patients were reviewed retrospectively for the following clinical manifestations: visual acuity, refraction, ocular alignments, ocular motility, head position, magnetic resonance imaging, surgical techniques, and outcomes.

RESULTS

All 4 cases were diagnosed as variants of Duane retraction syndrome. Two cases (cases 1 and 2) had synergistic divergence with unilateral adduction deficit, and 2 (cases 3 and 4) had synergistic convergence with bilateral abduction deficit. Case 2 manifested abnormal vertical movements of the right eye, which goes down with adduction of the left eye and goes up oppositely with abduction of left eye. Accessory fibrotic bands were detected beside the medial rectus muscle of both eyes in case 3. Synergistic convergence in case 4 occurred only after the first strabismus surgery. Weakening of the misinnervated horizontal rectus muscle improved ocular alignment and head position in cases 1, 3, and 4.

CONCLUSIONS

Synergistic divergence and convergence are extremely rare and may present with a great diversity of clinical features. A good outcome is very difficult to achieve; however, weakening of the misinnervated horizontal rectus muscle was therapeutic in these patients.

Magnetic Resonance Imaging in 14 Patients with Congenital Oculomotor Nerve Palsy

PURPOSE

To elucidate the imaging findings of congenital oculomotor nerve palsy by evaluating the oculomotor nerve and extraocular muscles on magnetic resonance (MR) imaging in a relatively large series of 14 patients with congenital oculomotor nerve palsy.

METHODS

Ophthalmologic examination of 14 consecutive patients diagnosed with congenital oculomotor nerve palsy, and MR imaging of the orbit and oculomotor nerves were performed.

RESULTS

Of the 14 patients with congenital oculomotor nerve palsy, 13 patients (93%) were unilateral and 12 patients (86%) had incomplete palsy. On MR imaging, 5 patients (36%) had hypoplasia or aplasia of the oculomotor nerve with variable degrees of extraocular muscle atrophy on the affected side. Of the 14 patients, nine (64%) had normal-sized oculomotor nerves with or without muscle atrophy. The most frequently involved muscles were the inferior rectus (64%) and medial rectus (50%), followed by the superior rectus (29%) and inferior oblique muscles (14%). None of the 14 patients showed an abnormal abducens nerve.

CONCLUSION

Congenital oculomotor nerve palsy was mostly incomplete and hypoplasia or aplasia of the oculomotor nerve was apparent in one third of patients showing variable degrees of extraocular muscle atrophy, mostly of the medial rectus and inferior rectus muscles.

Synergistic divergence: case series and literature review

Background

To present the data of a series of patients with synergistic divergence, to propose a different modality of surgical correction and to perform a literature review of such a rare entity.

Methods

A retrospective study was performed on all patients who presented with unilateral or bilateral synergistic divergence to the Ophthalmology Department, Cairo University, during the period from January 2007 to July 2016. The demographic data, the results of sensorimotor examination, the surgical procedures performed and the ophthalmological as well as the systemic findings of all patients were collected and tabulated. PubMed was searched for patients with features of synergistic divergence.

Results

Thirteen patients with features of synergistic divergence were identified. The mean age of the patients was 8.9±10.1 years (range 1–40 years). Only one case was orthotropic in the primary position. Lateral rectus orbital wall fixation combined with 8–10 mm medial rectus resection was done in 10 patients. The mean follow-up was 6.6±7.7 months. Exotropia was significantly reduced in all patients. All patients had complete disappearance of synergistic divergence after surgery. A total of 78 patients with features of synergistic divergence were identified from PubMed. Surgery was done for 37 patients. Synergistic divergence disappeared in patients who had lateral rectus extirpation or orbital wall fixation.

Conclusion

Synergistic divergence is a challenging rare condition. We propose that lateral rectus orbital wall fixation combined with medial rectus resection both improves the alignment in primary position and eliminates the synergistic divergence in such patients.

Marshall M. Parks Memorial Lecture: Ocular Motor Misbehavior in Children: Where Neuro-Ophthalmology Meets Strabismus

Clinical diagnosis has been supplemented by neuroimaging advances, genetic discoveries, and molecular research to generate new neurobiological discoveries pertaining to early maldevelopment of ocular motor control systems. In this focused review, I examine recent paradigm shifts that have transformed our understanding of pediatric ocular motor disease at the prenuclear and infranuclear levels. The pathogenesis of complex ocular motor disorders, such as paradoxical pupillary constriction to darkness, benign tonic upgaze of infancy, congenital fibrosis syndrome, and the constellation of unique eye movements that accompany Joubert syndrome, are elucidated.

Considerations on the etiology of congenital Brown syndrome

PURPOSE OF REVIEW

Brown syndrome is an ocular motility disorder characterized by limited volitional and passive elevation of the eye in adduction. Although originally thought due to abnormalities in the trochlea or tendon sheath (limiting the free movement of the tendon through the trochlea), recent evidence suggests that some cases of congenital Brown syndrome may be related to neurodevelopmental abnormalities of the extraocular muscles (congenital cranial dysinnervation disorders, CCDD).

RECENT FINDINGS

CCDD is a term encompassing congenital abnormalities of eye movements caused by congenital innervational abnormalities. The abnormal development of cranial nerve nuclei or abnormalities in cranial nerve axonal transport affects the development of the extraocular muscle(s). Currently, congenital fibrosis of the extraocular muscles, Duane syndrome, Moebius syndrome, Horizontal gaze palsy and progressive scoliosis, and synergistic divergence are included as CCDDs. In addition, congenial ptosis, Jaw Wink ptosis, and congenital superior oblique palsy are also included. Recently, it has been suggested that some cases of congenital Brown syndrome and congenital superior oblique paresis are related, and these entities may be part of the CCDDs spectrum.

SUMMARY

Important findings regarding the cause of congenital Brown syndrome will be reviewed.

Congenital and Genetic Ocular Motility Disorders: Update and Considerations

Concepts regarding certain forms of congenital eye movement disorders have recently changed, due in large part to new genetic evidence identifying causative genes and their role in the development of extraocular muscle innervation. This group is now referred to as the Congenital Cranial Dysinnervation Disorders (CCDDs). Careful assessment of phenotypic features that include both ophthalmological and non-ophthalmological features in genetically defined individuals has led to the development of a more robust classification system. Correlating phenotypes with new genetically defined syndromes has improved the ability of the clinician/researcher to better determine a definitive diagnosis in patients with complex ocular motility disorders. Nevertheless, more work is still required.

Possible association of congenital Brown syndrome with congenital cranial dysinnervation disorders

BACKGROUND

Congenital cranial dysinnervation disorders (CCDDs) are known to arise from abnormal development of individual and multiple cranial nerve nuclei or abnormalities in cranial nerve axonal transport. We report our findings for several patients with Brown syndrome in association with other known abnormalities characteristic of CCDDs.

METHODS

The medical records of patients presenting during a 4-year period with congenital Brown syndrome were retrospectively reviewed. Patients with Brown syndrome confirmed by forced ductions were included in the study if the Brown syndrome was associated with either an abnormal development of the superior oblique muscle or superior oblique paresis, ptosis, Duane syndrome, or other known CCDDs.

RESULTS

A total of 9 patients with Brown syndrome were identified. Of these, 3 also demonstrated a contralateral superior oblique palsy; 2, a contralateral Duane syndrome; 1, an ipsilateral congenital ptosis; and 3, a moderate to severely hypoplastic ipsilateral superior oblique muscle.

CONCLUSIONS

Some patients with congenital Brown syndrome are associated with and possibly in the spectrum of CCDDs. We propose that Brown syndrome may be due to abnormal development of the trochlear nerve, which results in physical changes in the superior oblique muscle-tendon-trochlea complex. This results in a tendon that is either long and lax, absent, or abnormally inserted (ie, superior oblique paresis) or a tendon that is restricted in its movements through the trochlea (Brown syndrome).

Congenital innervation dysgenesis syndrome (CID)/congenital cranial dysinnervation disorders (CCDDs)

Congenital loss of innervation to the extra-ocular muscles (EOMs) can have a profound effect on the target muscle. This has been well recognised in Duane's retraction syndrome. However, it has been less emphasised in other congenital oculo-motor disorders. Such congenital ocular motor defects have been expanded to include DRS, congenital fibrosis of EOMs, monocular elevation defect, Möbius syndrome, as well as several other non-ocular muscles supplied by cranial nerves such as facial muscles. Such loss of innervation to motor muscles can be unified as a defined clinical entity, which can be labelled as congenital innervation dysgenesis syndrome or CID for short. CID may also affect other muscles supplied by nerves other than the cranial nerves and may be sensory as well as motor.

Atypical Duane's retraction syndrome: congenital adduction palsy with synergistic divergence in association with aberrant trigeminal innervation and facial hypoplasia

The authors describe the atypical and unique features of trigeminal-oculomotor synkinesis in a 6-year-old boy with left congenital adduction palsy and synergistic divergence with facial hypoplasia. Adducting movements of the left eye were also seen on mastication. To the best of the authors' knowledge, a case of this nature has not previously been reported. This case illustrates the absence of changes in palpebral aperture and globe retraction on attempted adduction and also the complete absence of any abduction deficit of the involved eye. Additionally, presence of adducting movements on mastication suggests a trigemino-oculomotor synkinesis. Hypothesis favors an anomalous innervation of the medial rectus muscle from the motor branch of the trigeminal nerve that innervates the external pterygoids.

KIF21A variant R954W in familial or sporadic cases of CFEOM1

PURPOSE

To demonstrate the clinical characteristics and determine mutations in the KIF21A gene, encoding a kinesin motor protein in patients with congenital fibrosis of the extraocular muscles (CFEOM) type 1.

METHODS

Patients of five families with congenital fibrosis syndrome and two simplex patients with CFEOM underwent ophthalmologic examination and mutation analysis in the KIF21A gene.

RESULTS

Clinical examination and passive motility testing prior to surgery met criteria for CFEOM. All patients had congenital restrictive ophthalmoplegia primarily affecting muscles innervated by the oculomotor nerve. Complete mutation screening in the KIF21A gene revealed the presence of the known and most common recurrent variant R954W in three families and in two simplex cases. Two families demonstrated linkage to chromosome 16.

CONCLUSIONS

The patients included in the study had marked restriction of movement bilaterally with nearly complete loss of vertical ocular motility, graded reduction of horizontal motility, ptosis, and compensatory chin elevation. The phenotype was variable in patients carrying the same mutation. In one family, all patients were diagnosed with mental retardation, indicating that this syndrome might not only affect the development of cranial nerves, but can also be responsible for general neurologic dysfunction. The screening data suggest frequent and exclusive appearance of the R454W variant in sporadic and familial cases of CFEOM1 in Germany.

Management of congenital fibrosis of the inferior rectus muscle associated with high myopia: a case report

BACKGROUND

Congenital fibrosis of the extraocular muscles includes a wide spectrum of phenotypically heterogeneous disorders involving a single or multiple muscles.

METHODS

We present a case of congenital fibrosis of the inferior rectus associated with ipsilateral high myopia. First we tried to treat the hypotropia with inferior rectus weakening and superior rectus strengthening procedures, but this failed, so we proceeded with an ocular sling with fascia lata and a vertical Hummelsheim procedure.

RESULTS

Hypotropia improved completely after the last operation and some degree of upward movement appeared.

CONCLUSION

It seems that in a highly myopic globe with fibrotic muscles, classical methods for the correction of deviation may have poor response and more innovative procedures may be required to correct the deviation.

Towards an understanding of congenital ptosis

This paper examines the developmental substrate for congenital ptosis with particular emphasis on the transcription factors that are thought to be involved. We summarize my research findings and present a review of the relevant literature.

Die kongenitale Fibrose der äußeren Augenmuskeln (CFEOM) und andere Phänotypen der kongenitalen kranialen Dysinnervationssyndrome (CCDD)

Currently, different syndromes with congenital, nonprogressive, sporadic, or familial developmental abnormalities of the cranial nerves and its nuclei are classified as congenital cranial dysinnervation syndromes (CCDD). One of these syndromes, congenital fibrosis of extraocular muscles (CFEOM), is characterized mainly by bilateral ophthalmoplegia of the oculomotor and trochlear nerves. Within the scope of an overview, the case of a 60-year-old patient with congenital fibrosis of extraocular muscles type 1 (CFEOM1) with autosomal dominant inheritance and typical phenotype, but additional progression of the ocular symptoms, is presented. Symptoms were caused by the common C2860-->T mutation in exon 21 of the KIF21A gene on chromosome 12. Further CCDD syndromes include the following phenotypes: congenital ptosis, Duane syndrome, horizontal gaze palsy, Möbius' syndrome, and congenital facial palsy. There are 13 different known gene loci for one of these phenotypes. Five gene products have been identified: the kinesin motor protein Kif21a, the transcription factors ARIX and SALL4, and the carboxypeptidase CPAH.

Applications of molecular genetics to the understanding of congenital ocular motility disorders

The congenital fibrosis syndromes (CFS), including congenital fibrosis of the extraocular muscles (CFEOM) and Duane syndrome (DS), are rare congenital strabismus syndromes that present with nonprogressive restrictive ophthalmoplegia with or without ptosis. Although historically believed to result from primary extraocular muscle (EOM) fibrosis, our laboratory's work is based on the hypothesis that these disorders result from distinct, but analogous, developmental defects of the oculomotor (nIII), trochlear (nIV), and abducens (nVI) nuclei. We have defined three inherited CFEOM phenotypes (CFEOM1-3) and have mapped each phenotype to a distinct genetic locus (FEOM1-3). Individuals with CFEOM1 are born with bilateral ptosis and both eyes fixed in a downward position with absent upgaze and aberrant horizontal gaze. This disorder maps to the FEOM1 locus on chromosome 12cen.(1,2) Neuropathology studies of CFEOM1 reveal the absence of the superior division of oculomotor nerve and its corresponding alpha motor neurons in the midbrain, with abnormalities of target EOMs.(3) These neuropathology findings parallel those previously identified in Duane syndrome, in which there is an absence of nVI and the abducens nerve.(4,5) Individuals with CFEOM2 are born with bilateral ptosis and exotropia. This atypical form of CFEOM maps to the FEOM2 locus on chromosome 11q13 and results from mutations in ARIX (PHOX2A).(6,7) ARIX encodes a homeodomain transcription factor protein previously shown to be required for nIII/nIV development in mouse and zebrafish.(8,9) Together, these findings support the hypothesis that the congenital fibrosis syndromes result from parallel defects in nIII, nIV, and nVI nuclear development. Functional studies of the CFEOM genes should provide additional insight into the unique features of the extraocular lower motor neuron axis in health and disease. (For full (refs. 1-9), see reference list of the main paper.)

Congenital fibrosis of the extraocular muscles associated with cortical dysplasia and maldevelopment of the basal ganglia

BACKGROUND

Congenital fibrosis of the extraocular muscles (CFEOM) is a rare condition that has been traditionally regarded as a primary eye muscle disease. Recent studies, however, suggest that CFEOM may be the result of a primary neuropathy with secondary myopathic changes.

PURPOSE

To describe a previously unrecognized association between congenital fibrosis of the extraocular muscles and structural abnormalities of the brain.

DESIGN

Small case series.

METHODS

Detailed clinical examinations and neuroradiologic studies were performed on the three affected family members. In addition, genetic analysis of the family was performed.

RESULTS

The three affected family members, mother and two children, have the ocular features of 'classic' congenital fibrosis of the extraocular muscles. All showed dilation of the left lateral ventricle secondary to hypoplasia of the body and tail of the ipsilateral caudate nucleus. There was fusion of an enlarged caudate nucleus head with the underlying putamen. Both children showed widespread bilateral cortical dysplasia. Genetic analysis of the family was inconclusive but consistent with linkage to the CFEOM1 locus on chromosome 12. Chromosomal analysis of the affected individuals did not show evidence of a deletion of chromosome 12 and haplotype analysis was not suggestive of a microdeletion.

CONCLUSIONS

Cerebral cortical and basal ganglia maldevelopment can be found in individuals with CFEOM. This suggests that neuroimaging should be considered in the initial diagnostic evaluation of these patients, particularly if there is developmental delay.

Locus heterogeneity in autosomal dominant congenital external ophthalmoplegia (CFEOM)

Congenital external ophthalmoplegia (CFEOM) is an uncommon autosomal dominant condition that has previously been mapped to the pericentromeric region of chromosome 12 in seven families with no evidence of locus heterogeneity. We report three families with typical CFEOM. One family does not map to this region of chromosome 12 or to other chromosomal locations implicated in disorders of lid or ocular movement. Recombinants in two CFEOM families potentially help to reduce the size of the candidate region on chromosome 12.

Treatment of congenital adduction palsy with synergistic divergence

OBJECTIVE

To report on successful management of congenital adduction palsy with synergistic divergence by performing weakening surgery on the superior and inferior oblique muscles.

METHODS

We performed a total tenotomy of the lateral rectus muscle, followed by resection of the medial rectus muscle and tenotomy of the superior oblique and myectomy of the inferior oblique muscles in a patient who had congenital adduction palsy with synergistic divergence.

RESULTS

Total tenotomy of the lateral rectus muscle had no effect on synergistic divergence, resection of the medial rectus muscle reduced it to some extent and tenotomy of the superior oblique and myectomy of the inferior oblique muscles further reduced this phenomenon. The improvement in synergistic divergence was maintained at 2 1/2 years later at follow up.

CONCLUSIONS

Weakening surgery on the superior and inferior oblique muscles should be considered in the management of synergistic divergence.

Hereditary external ophthalmoplegia synergistic divergence, jaw winking, and oculocutaneous hypopigmentation: a congenital fibrosis syndrome caused by deficient innervation to extraocular muscles

BACKGROUND

The congenital fibrosis syndrome is a hereditary form of external ophthalmoplegia that is considered to be a primary myopathy.

PURPOSE

To document the coexistence of two distinct forms of ocular motor synkinesis in a subgroup of patients with congenital fibrosis syndrome.

METHODS

Clinical and intraoperative examination results and extraocular muscle biopsy specimens from four patients with congenital fibrosis syndrome were studied.

RESULTS

Three patients displayed a variant of synergistic divergence characterized by simultaneous abduction with intorsion and depression of the synkinetically abducting eye. Three patients had variant of Marcus Gunn jaw winking characterized by elevation of a ptotic eyelid during mouth opening. Three patients had oculocutaneous hypopigmentation.

CONCLUSIONS

A subgroup of patients with congenital fibrosis syndrome display two distinct synkinetic ocular movements in conjunction with oculocutaneous hypopigmentation. The patterns of neuronal misdirection implicate a regional innervational disturbance involving cranial nerves III through VI as the underlying cause of diffuse hereditary ophthalmoplegia in these patients.

Oculomotor nerve and muscle abnormalities in congenital fibrosis of the extraocular muscles

Congenital fibrosis of the extraocular muscles is an autosomal dominant congenital disorder characterized by bilateral ptosis, restrictive external ophthalmoplegia with the eyes partially or completely fixed in an infraducted (downward) and strabismic position, and markedly limited and aberrant residual eye movements. It has been generally thought that these clinical abnormalities result from myopathic fibrosis of the extraocular muscles. We describe the intracranial and orbital pathology of 1 and the muscle pathology of 2 other affected members of a family with chromosome 12-linked congenital fibrosis of the extraocular muscles. There is an absence of the superior division of the oculomotor nerve and its corresponding alpha motor neurons, and abnormalities of the levator palpebrae superioris and rectus superior (the muscles innervated by the superior division of the oculomotor nerve). In addition, increased numbers of internal nuclei and central mitochondrial clumping are found in other extraocular muscles, suggesting that the muscle pathology extends beyond the muscles innervated by the superior division of cranial nerve III. This report presents evidence that congenital fibrosis of the extraocular muscles results from an abnormality in the development of the extraocular muscle lower motor neuron system.

Congenital ocular aberrant innervation--new concepts

BACKGROUND

We have the impression that congenital aberrant innervations are more common than previously reported. Many varieties exist and typically involve the sixth nerve. The most common ocular miswirings are Duane's syndrome and Marcus Gunn jaw-winking ptosis. The second most common miswiring involves lateral rectus activation in upgaze causing a "Y" pattern exotropia (pseudo inferior oblique overaction). This commonly is confused with inferior oblique overaction but surgery on the obliques does not cure the condition. Lateral rectus recession and elevation are required.

METHODS

We selected demonstrative cases from our practices to illustrate a variety of congenital aberrant innervations. A literature search for previous reported cases of aberrant innervations was performed. This report is an eclectic collection of observations of individual selected cases.

RESULTS

We found aberrant innervations of unusual varieties. These miswirings involve simultaneous firing of the lateral rectus with other muscles, including: the ipsilateral superior rectus, causing "pseudo inferior oblique overaction"; the contralateral lateral rectus, causing synergistic divergence; the ipsilateral superior rectus, in upward saccades only; and the masticatory muscles, causing exotropia with sucking. The third nerve by itself rarely is involved in congenital miswirings, but commonly shows aberrant regeneration after traumatic injuries. We know of no cases of aberrant innervation involving the fourth nerve.

SUMMARY

We present cases describing these congenital aberrant innervations and discuss a unifying hypothesis as to their typical involvement of the sixth nerve.

Congenital fibrosis of the vertically acting extraocular muscles. A new group of dominantly inherited ocular fibrosis with radiologic findings

BACKGROUND

The authors studied a family with a form of congenital fibrosis of the extraocular muscles different from any group previously reported.

METHODS

A careful examination was done of all affected and all, except one, unaffected members of a family of 15 members extending over three generations. The authors performed computed tomography on five affected and four unaffected family members.

RESULTS

All affected family members showed complete loss of vertical ocular movement but largely free horizontal movement except for variable restriction of adduction in some members. A variable degree of ptosis was present, ranging from gross to nil, but with poor levator function and an absent Bell phenomenon in all affected members. All affected members showed superficial keratopathy, many with corneal scarring. Ocular alignment showed considerable variation. Refractive error and amblyopia also were variable. Computed tomographic scan indicated reduction in size of the extraocular muscles, particularly the superior recti with intracranial ventricular asymmetry in three of five patients examined, and abnormality in shape of the eye globes in two patients.

CONCLUSIONS

The findings indicate a new group best described as dominantly inherited congenital fibrosis of the vertical-acting extraocular muscles, which is part of the syndrome of congenital ocular fibrosis. Computed tomographic scanning suggested that the clinical picture was produced by changes present in the orbit, but intracranial ventricular asymmetry also was present in some patients and asymmetry of the eye globes in others.

Mapping a gene for congenital fibrosis of the extraocular muscles to the centromeric region of chromosome 12

Congenital Fibrosis of the Extraocular Muscles (CFEOM) is an autosomal dominant, ocular disorder characterized by congenital, nonprogressive, bilateral ptosis and external ophthalmoplegia. The pathophysiology of this disorder is unknown and it is unclear if it has a primary neurogenic or myopathic etiology. We report linkage of this disorder, in two unrelated families, to markers in the pericentromeric region of human chromosome 12. D12S59 does not recombine with the disease giving a two-point lod score of 12.5 (theta = 0.00). D12S87 and D12S85 flank the CFEOM locus with two-point lod scores of 8.9 (theta = 0.03) and 5.4 (theta = 0.03) respectively, defining a region of 8 cM. These data establish a map location for CFEOM and demonstrate that this may be a genetically homogeneous disorder.

Synergistic divergence: saccadic velocity analysis and surgical results

The clinical findings are described in four patients with synergistic divergence (SD), an ocular motility disorder which is considered to be a variant of Duane retraction syndrome (DRS). Saccadic velocity studies in three patients demonstrated preserved abducting saccades in the affected eye with equally reduced amplitudes on both attempted abduction and adduction. The preserved saccades on attempted abduction of the affected eye, coupled with electromyographic evidence that shows maintenance of normal reciprocal innervation with respect to gaze on attempted abduction as dictated by Sherrington's law, strongly suggest that the abducens nerve is not necessarily absent or severely hypoplastic in this condition. One patient showed typical DRS in the contralateral eye and had a son with bilateral DRS, attesting to a possible genetic and etiologic relationship between SD and DRS. Three patients underwent strabismus surgery. Review of our surgical results and an analysis of the literature indicate that a crippling procedure to the ipsilateral lateral rectus muscle, such as extirpation, may be necessary to eliminate simultaneous abduction. Overcorrection did not occur following lateral rectus extirpation.

Congenital ocular fibrosis with musculoskeletal abnormality: a new association

Two siblings demonstrated an association of congenital ocular fibrosis (COF) syndrome with musculoskeletal abnormalities consisting of generalized muscle wasting, scoliosis, pigeon-chest deformity, bilateral fusion of the ribs in triplets, prominent coccyx, and sacral dimple. While most of the ocular and systemic "associations" hitherto described in the literature might have been coincidental, the coexistence of a generalized musculloskeletal disease with the COF syndrome raises the possibility that the ocular condition may be part of a more widespread disease process affecting the skeletal muscles.