the proband , a six and a half - year - old girl , [ figure 1 ] presented 
 with the parental observation of poor elevation of her left eye 
 towards her nose from infancy . her mother had also been 
 diagnosed as having brown syndrome in her childhood , for 
 which a strabismus surgery had been performed when she 
 was one year old . on examination , the child had a visual 
 acuity of 20/40 in the right eye and 20/30 in the left eye with a 
 stereo acuity of 500 seconds of arc . stereo acuity was tested 
 at near using the titmus test ( stereo optical , chicago , il ) 
 as per the manufacturers instructions . her ocular motility 
 showed limited dextro - elevation of the left eye with down 
 shoot on adduction . an annual orthoptic follow - up was recommended with the 
 advice that no treatment was required unless the child was 
 symptomatic with a deviation in the primary position or 
 on down gaze . given the positive family history of brown 
 syndrome a clinical examination of the siblings and mother 
 was carried out . this was the four and a half - year - old younger sister of the 
 proband [ figure 1 ] . on examination , the visual acuity was 
 20/20 bilaterally with a stereo acuity of 100 seconds of arc 
 using the titmus stereo acuity test . her ocular motility 
 examination revealed a limitation of dextro - elevation of the left 
 eye [ figure 3 ] . the cover test showed 2 diopters of exophoria 
 for distance and 4 diopters of exophoria for near . a diagnosis of familial 
 brown syndrome was made and this patient , akin to her sister 
 mentioned above was recommended an annual orthoptic 
 review . review of the records showed that the 41-year - old lady , who was 
 the mother of the above children ( the proband and her sibling ) 
 [ figure 1 ] had been diagnosed as having a left eye superior 
 oblique tendon sheath syndrome . a left superior oblique partial 
 tenotomy procedure had been performed at one year of age . her ocular motility examination showed persistent limited 
 elevation on adduction of the left eye [ figure 4 ] consistent with 
 a diagnosis of a left brown syndrome . as she was asymptomatic 
 and her visual axes parallel in the primary position and in down 
 gaze , no further treatment or follow - up the probands eldest sister , who was12 years old , and 
 youngest brother , who was one year old , were examined and 
 did not show any extraocular motility abnormality [ figure 1 ] . 
 yearly review of the brother has been recommended . the 
 father was not available for examination but he was not 
 known to have any extraocular motility abnormalities . the proband , a six and a half - year - old girl , [ figure 1 ] presented 
 with the parental observation of poor elevation of her left eye 
 towards her nose from infancy . her mother had also been 
 diagnosed as having brown syndrome in her childhood , for 
 which a strabismus surgery had been performed when she 
 was one year old . on examination , the child had a visual 
 acuity of 20/40 in the right eye and 20/30 in the left eye with a 
 stereo acuity of 500 seconds of arc . stereo acuity was tested 
 at near using the titmus test ( stereo optical , chicago , il ) 
 as per the manufacturers instructions . her ocular motility 
 showed limited dextro - elevation of the left eye with down 
 shoot on adduction . an annual orthoptic follow - up was recommended with the 
 advice that no treatment was required unless the child was 
 symptomatic with a deviation in the primary position or 
 on down gaze . given the positive family history of brown 
 syndrome a clinical examination of the siblings and mother 
 was carried out . this was the four and a half - year - old younger sister of the 
 proband [ figure 1 ] . on examination , the visual acuity was 
 20/20 bilaterally with a stereo acuity of 100 seconds of arc 
 using the titmus stereo acuity test . her ocular motility 
 examination revealed a limitation of dextro - elevation of the left 
 eye [ figure 3 ] . the cover test showed 2 diopters of exophoria 
 for distance and 4 diopters of exophoria for near . a diagnosis of familial 
 brown syndrome was made and this patient , akin to her sister 
 mentioned above was recommended an annual orthoptic 
 review . no surgical treatment was required . review of the records showed that the 41-year - old lady , who was 
 the mother of the above children ( the proband and her sibling ) 
 [ figure 1 ] had been diagnosed as having a left eye superior 
 oblique tendon sheath syndrome . a left superior oblique partial 
 tenotomy procedure had been performed at one year of age . her ocular motility examination showed persistent limited 
 elevation on adduction of the left eye [ figure 4 ] consistent with 
 a diagnosis of a left brown syndrome . as she was asymptomatic 
 and her visual axes parallel in the primary position and in down 
 gaze , no further treatment or follow - up the probands eldest sister , who was12 years old , and 
 youngest brother , who was one year old , were examined and 
 did not show any extraocular motility abnormality [ figure 1 ] . 
 yearly review of the brother has been recommended . the 
 father was not available for examination but he was not 
 known to have any extraocular motility abnormalities . the mother and her two daughters described here presented 
 with defective dextro - elevation of the left eye since childhood 
 and their ocular motility examination was consistent with 
 left brown syndrome . although the mother had undergone a 
 corrective surgery in childhood , neither of the daughters had 
 any indication for surgical intervention . the incidence of familial brown syndrome is believed to be 
 one in 20,000 live births . it equally affects males and females 
 and is bilateral in about 10% of cases.10 brown syndrome 
 together with duanes syndrome and congenital fibrosis of the 
 extraocular muscles ( cfeom ) have been classified by brown 
 as the congenital fibrosis syndromes based on the findings of 
 both active and passive restriction of ocular motility and the 
 congenital non - progressive nature of the condition.1 unlike 
 brown syndrome , genetic studies have shed light on the 
 etiology of both duanes syndrome and cfeom . heterozygous 
 mutations in kif21a have been reported in cfeom1 and 311 
 and cfeom2 has been attributed to mutation in phox2a/ 
 arix gene.12 while no gene defect has been identified for 
 isolated duanes syndrome , durs2 locus on chromosome 2 
 has been mapped , and sall4 and hoxa1 were reported in 
 other associated anomalies.13 iannacone et al.,5 described unilateral brown syndrome in 
 an italian family and excluded linkage to the known cfeom 
 gene arix and the feom3 locus . an autosomal recessive or 
 an autosomal dominant inheritance with reduced penetrance 
 was postulated . to our knowledge this is the first report to identify 
 three members of two generations of the same family with 
 ipsilateral left - sided brown syndrome . although no genetic 
 workup was carried out , the clinical presentation of the cases 
 in this report is suggestive of possible autosomal dominant 
 transmission . our family supports previous literature reports of possible 
 autosomal dominant inheritance in brown syndrome , and 
 suggests that the phenotype can breed true in terms of laterality . we recommend genetic counseling in all brown syndrome cases 
 and their families as to the probabilities of inheritance .
we present a two - generation family with brown syndrome . 
 the 
 proband was a six and a half - year - old female who presented 
 with a history of failure of dextro - elevation of her left eye . 
 a 
 full ophthalmic evaluation was consistent with a left brown 
 syndrome . 
 family history revealed that her mother was operated 
 on as a child for left brown syndrome and examination of her 
 four and a half - year - old sibling showed similar affection in the 
 left eye . 
 autosomal dominant inheritance has been postulated 
 in this condition . to our knowledge 
 this is the first report of 
 three members of a two - generation family with left - sided brown 
 syndrome . 
 genetic counseling of brown syndrome cases is 
 advised ; nevertheless , identification of the responsible gene 
 should shed more light on its genetics .