Ophthalmic features of ataxia telangiectasia-like disorder.
BACKGROUND
Ataxia telangiectasia (AT) is a recessive neurodegenerative disease due to a faulty repair mechanism for breaks in double-stranded DNA (ATM mutation). Ophthalmic features of AT include conjunctival telangiectasia, strabismus, saccadic dysfunction with head thrusts, and convergence insufficiency. Ataxia telangiectasia-like syndrome (ATLD) is a more recently recognized condition due to homozygous mutation in MRE11, a gene also involved in the cellular repair response to double-stranded DNA breaks; ophthalmic features of ATLD are not well described. The purpose of this article is to describe the ophthalmic features of ATLD.


METHODS
Full ophthalmologic and orthoptic evaluations were obtained in 13 individuals: 10 previously reported ATLD patients, an additional related ATLD patient, and 3 nonaffected relatives. All individuals were from three unrelated consanguineous Saudi Arabian families harboring an MRE11 mutation (W210C). Age range was from 2 to 40 years of age.


RESULTS
No affected patient had structural ocular abnormality (eg, conjunctival telangiectasia), manifest strabismus at distance, or duction limitation. All but one (the youngest) had saccadic dysfunction (without head thrusts). Most patients had abnormal convergence. Older patients had nystagmus with abnormalities in smooth pursuit and vestibular ocular reflex. All patients had cerebellar atrophy by neuroimaging and slowly progressive ataxia. The unaffected heterozygous relatives had unremarkable ophthalmic and neurologic examinations.


CONCLUSIONS
Saccadic dysfunction without head thrusts and convergence abnormality are common in ATLD secondary to homozygous W210C MRE11 mutation. Older patients have nystagmus with abnormalities in smooth pursuit and vestibular ocular reflex. Eye movement control systems apparently deteriorate with time in this rare neurological disease. Ophthalmic features of AT that were not observed in any of our ATLD patients include conjunctival telangiectasia, head thrusting, and manifest strabismus at distance.
Khan
Arif O
AO
Division of Pediatric Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia. arif.khan@mssm.edu
Oystreck
Darren T
DT
Koenig
Michel
M
Salih
Mustafa A
MA
D000293:Adolescent; D000328:Adult; D001260:Ataxia Telangiectasia / Q000235:genetics / Q000503:physiopathology*; D064007:Ataxia Telangiectasia Mutated Proteins; D001921:Brain / Q000473:pathology; D018797:Cell Cycle Proteins / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D003241:Consanguinity; D004268:DNA-Binding Proteins / Q000235:genetics; D005133:Eye Movements; D006801:Humans; D000076228:MRE11 Homologue Protein; D008279:Magnetic Resonance Imaging; D009154:Mutation; D009885:Ophthalmology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D011698:Pursuit, Smooth / Q000502:physiology; D012438:Saccades; D012529:Saudi Arabia; D025521:Tumor Suppressor Proteins / Q000235:genetics
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C121766:MRE11 protein, human; D025521:Tumor Suppressor Proteins; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases; D000076228:MRE11 Homologue Protein