Occurrence of CYP1B1 Mutations in Juvenile Open-Angle Glaucoma With Advanced Visual Field Loss

IMPORTANCE

Juvenile open-angle glaucoma (JOAG) is a severe neurodegenerative eye disorder in which most of the genetic contribution remains unexplained.

OBJECTIVE

To assess the prevalence of pathogenic CYP1B1 sequence variants in an Australian cohort of patients with JOAG and severe visual field loss.

DESIGN, SETTING, AND PARTICIPANTS

For this cohort study, we recruited 160 patients with JOAG classified as advanced (n = 118) and nonadvanced (n = 42) through the Australian and New Zealand Registry of Advanced Glaucoma from January 1, 2007, through April 1, 2014. Eighty individuals with no evidence of glaucoma served as a control group. We defined JOAG as diagnosis before age 40 years and advanced JOAG as visual field loss in 2 of the 4 central fixation squares on a reliable visual field test result. We performed direct sequencing of the entire coding region of CYP1B1. Data analysis was performed in October 2014.

MAIN OUTCOMES AND MEASURES

Identification and characterization of CYP1B1 sequence variants.

RESULTS

We identified 7 different pathogenic variants among 8 of 118 patients with advanced JOAG (6.8%) but none among the patients with nonadvanced JOAG. Three patients were homozygous or compound heterozygous for CYP1B1 pathogenic variants, which provided a likely basis for their disease. Five patients were heterozygous. The allele frequency among the patients with advanced JOAG (11 in 236 [4.7%]) was higher than among our controls (1 in 160 [0.6%]; P = .02; odds ratio, 7.8 [95% CI, 0.02-1.0]) or among the control population from the Exome Aggregation Consortium database (2946 of 122 960 [2.4%]; P = .02; odds ratio, 2.0 [95% CI, 0.3-0.9]). Individuals with CYP1B1 pathogenic variants, whether heterozygous or homozygous, had worse mean (SD) deviation on visual fields (-24.5 [5.1] [95% CI, -31.8 to -17.2] vs -15.6 [10.0] [95% CI, -17.1 to -13.6] dB; F1,126 = 5.90; P = .02; partial ηp2 = 0.05) and were younger at diagnosis (mean [SD] age, 23.1 [8.4] [95% CI, 17.2-29.1] vs 31.5 [8.0] [95% CI, 30.1-33.0] years; F1,122 = 7.18; P = .008; ηp2 = 0.06) than patients without CYP1B1 pathogenic variants.

CONCLUSIONS AND RELEVANCE

Patients with advanced JOAG based on visual field loss had enrichment of CYP1B1 pathogenic variants and a more severe phenotype compared with unaffected controls and patients with nonadvanced JOAG.

CYP1B1 copy number variation is not a major contributor to primary congenital glaucoma

PURPOSE

To evaluate the prevalence and the diagnostic utility of testing for CYP1B1 copy number variation (CNV) in primary congenital glaucoma (PCG) cases unexplained by CYP1B1 point mutations in The Australian and New Zealand Registry of Advanced Glaucoma.

METHODS

In total, 50 PCG cases either heterozygous for disease-causing variants or with no CYP1B1 sequence variants were included in the study. CYP1B1 CNV was analyzed by Multiplex Ligation-dependent Probe Amplification (MLPA).

RESULTS

No deletions or duplications were found in any of the cases.

CONCLUSION

This is the first study to report on CYP1B1 CNV in PCG cases. Our findings show that this mechanism is not a major contributor to the phenotype and is of limited diagnostic utility.

Superselective intra-arterial chemotherapy for advanced retinoblastoma complicated by metastatic disease

We present a case of a child with unilateral group E retinoblastoma (according to the International Classification of Retinoblastoma) who received superselective intra-arterial chemotherapy as primary therapy. Although the tumor showed signs of regression, the patient developed orbital metastases requiring surgical excision and chemotherapy. Eventually the affected eye progressed to total retinal detachment and required enucleation.

Scedosporium prolificans endogenous endophthalmitis

Scedosporium prolificans is an opportunistic fungus with a predilection for sepsis and endophthalmitis in immunocompromised patients. We report a case of endogenous S. prolificans endophthalmitis in a 9-year-old girl following chemotherapy for acute myeloid leukemia. She achieved an excellent visual outcome following intensive antifungal therapy.

Familial Transmission Risk of Infantile Glaucoma in Australia

PURPOSE

Primary infantile glaucoma (PIG) is predominantly inherited as a recessive disease, whereas anterior segment dysgenesis (ASD) is usually dominantly inherited. The purpose of this study was to determine the likelihood of a person who has infantile glaucoma to produce a child who also manifests the disease.

METHODS

A retrospective cross-sectional design was utilized. The pedigrees of probands from south-eastern Australia diagnosed with infantile glaucoma since 1980 were reviewed. Cases were subdivided into two groups according to the presence or absence of ASD. Exclusion criteria included incomplete pedigree phenotype information or aphakic glaucoma following congenital cataract surgery. Fisher's exact test was used to compare the parent-offspring phenotype transmission between ASD-associated infantile glaucoma and PIG.

RESULTS

A total of 67 probands were identified; however, three pedigrees were excluded due to incomplete phenotype information. Direct parent-offspring transmission of phenotype was statistically significantly more common in ASD-associated infantile glaucoma (2/8) than in PIG (1/56) pedigrees (p = 0.039).

CONCLUSIONS

Although this study reveals that Australian patients with ASD-associated infantile glaucoma are at greater risk of having children with infantile glaucoma than patients with PIG, the number of ASD pedigrees with direct transmission of infantile glaucoma is lower than expected. Based on our population frequency analysis and the results of our study, the risk of PIG, if one parent is affected by PIG and the other is normal, is less than 2%.

Ophthalmologic presentation of oxidative phosphorylation diseases of childhood

To investigate ophthalmologic manifestations in children with definitive oxidative phosphorylation disorders, a retrospective review was conducted of clinical and laboratory records of all such pediatric patients (n = 103) diagnosed and treated at one center between 1983 and 2006. All were residents of Victoria, Australia. Nystagmus or roving eye movements were the most common ophthalmologic manifestations as a presenting symptom of disease (13/20) and were the sole manifestation at presentation in 10/13 patients. Divergent strabismus was a presenting symptom in 5/20 patients and was the sole manifestation at presentation in 3/20 patients. Abnormal eye movements were noted in 6 patients and strabismus was noted in 4 patients with Leigh's or Leigh-like disease; in 9 of these 10 patients, Leigh's disease was the result of complex I deficiency. Altogether, ophthalmologic manifestations were noted at presentation in 12/35 patients with complex I deficiency. External ophthalmoplegia in conjunction with ptosis was the presenting symptom in 3/20 patients, all with Kearns-Sayers syndrome. Patients suspected of having oxidative phosphorylation disorders should be referred for ophthalmologic examination. Prospective studies are needed for a comprehensive elucidation of the ophthalmologic findings in these disorders.

Management of congenital elevation deficiency due to congenital third nerve palsy and monocular elevation deficiency

PURPOSE

To document the presentation and management of congenital III nerve palsy and monocular elevation deficiency to single ophthalmologist over a 14-year period. Surgical management was reviewed and visual outcome was analysed.

METHODS

A retrospective study was conducted of all patients presenting during a period between 1992 and 2006 to the private practice of a paediatric ophthalmologist, with either congenital III or monocular elevation deficiency. For patients requiring surgical intervention pre- and post-surgical data were documented and analysed.

RESULTS

A total of 19 congenital III and 13 monocular elevation deficiency patients were identified. There were eight surgical patients in each congenital III nerve palsy group and in the monocular elevation deficiency group. The congenital III group had a preoperative mean exotropia for near of -36 prism dioptres (PD) compared with postoperative mean exotropia for near -16 PD. Preoperative mean hypotropia for near of -19 PD was improved to postoperative mean hypotropia of -5 PD. The monocular elevation deficiency group had preoperative mean esotropia for near of +6 PD compared with postoperative mean exotropia for near -5 PD. Preoperative mean hypotropia for near of -15 PD was improved to postoperative mean hypotropia of -7 PD. At last follow up both groups had a majority of mild or no amblyopia noted.

CONCLUSION

Superficially, congenital III and monocular elevation deficiency may appear similar, both frequently having ptosis and hypotropia as features. Careful clinical assessment of the horizontal alignment and the result of forced duction testing will usually allow them to be distinguished. Congenital III more frequently requires surgery for exotropia as well as surgery for hypotropia and monocular elevation deficiency more often requires surgery just for hypotropia. The ptosis surgery is similar for either diagnosis in this study. Significant cosmetic improvement, as well as excellent visual acuity outcomes can be achieved.

Prevalence of CYP1B1 mutations in Australian patients with primary congenital glaucoma

Analysis of CYP1B1 in primary congenital glaucoma (PCG) patients from various ethnic populations indicates that allelic heterogeneity is high, and some mutations are population specific. No study has previously reported the rate or spectrum of CYP1B1 mutations in Australian PCG patients. The aim of this study is to determine the frequency of CYP1B1 mutations in our predominately Caucasian, Australian cohort of PCG cases. Thirty-seven probands were recruited from South-Eastern Australia, along with 100 normal control subjects. Genomic DNA was extracted and the coding regions of CYP1B1 analysed by direct sequencing. Sequence analysis identified 10 different CYP1B1 disease-causing variants in eight probands (21.6%). Five subjects were compound heterozygotes, two subjects heterozygous and one homozygous for CYP1B1 mutations. Three missense mutations are novel (D192Y, G329D, and P400S). None of the novel mutations identified were found in normal controls. One normal control subject was heterozygous for the previously reported CYP1B1 R368H mutation. Six previously described probable polymorphisms were also identified. Mutations in CYP1B1 account for approximately one in five PCG cases from Australia. Our data also supported the high degree of allelic heterogeneity seen in similar studies from other ethnic populations, thereby underscoring the fact that other PCG-related genes remain to be identified.

Retrospective analysis of patients attending a neurofibromatosis type 1 clinic

AIM

To undertake a retrospective analysis of the patients who attended the neurofibromatosis type 1 clinic (NF clinic) at the Royal Children's Hospital, Melbourne between March 2001 and May 2004. From this analysis, we aimed to ascertain the frequency and nature of complications of NF1 in this cohort and compare this with other large series.

METHODS

Genetic files and hospital records of patients who attended the NF clinic were reviewed. Data regarding the clinical features and NF1-related complications present in the patient population were entered into a database and then analysed.

RESULTS

Data were available for 121 patients with presumed or confirmed diagnoses of NF1 who attended the NF clinic between the study dates. While most patients were referred to the clinic for 'routine surveillance', complications of NF1 were common. Forty-four per cent of patients had learning difficulties, 21% had optic gliomas and 17% had plexiform neurofibromas. Fifty-five per cent of those with plexiform neurofibromas required at least one surgical procedure.

CONCLUSION

The NF clinic was accessed by patients of all ages to assist with diagnosis, provide routine surveillance and manage complex complications of NF1. The prevalence and range of complications of NF1 of the patients attending this clinic is similar to other large retrospective studies in tertiary centres.

Postmortem orbital findings in shaken baby syndrome

PURPOSE

To compare postmortem orbital findings in pediatric accidental head injury to Shaken Baby Syndrome (SBS).

DESIGN

Retrospective study.

METHODS

SETTING

Institutional.

STUDY POPULATION

Thirty-six patients underwent postmortem modified exenteration with sectioning of the orbital contents; 18 victims of SBS and 18 cases of fatal accidental head trauma.

OBSERVATION PROCEDURE

In all cases of children who died from accidental head trauma, the orbital tissues were separated to expose the optic nerve sheath. Patients with gross evidence of hemorrhage within the sheath were included. All cases of SBS were included. After accidental head injury, exenteration was performed only if optic nerve sheath hemorrhage was suspected on gross examination. All children younger than 18 years old with head injury as primary cause of death were included. SBS is defined as having at least two of the following: (1) typical abnormal findings on neuroimaging, (2) typical skeletal injury, (3) retinal hemorrhages, (4) history of abusive shaking with or without blunt head trauma, or (5) an inadequate history to explain the observed injuries.

MAIN OUTCOME MEASURE

Presence or absence of orbital hemorrhage.

RESULTS

Orbital tissue injury is more common in SBS than accidental head trauma without orbital fracture. In addition, optic nerve sheath and optic nerve intradural hemorrhage are also significantly more common in SBS (P < .0001).

CONCLUSIONS

Our study reports new evidence of injury to orbital tissues in SBS and supports the concept that these finding are due to unique acceleration-deceleration forces of this type of abusive head injury.

Two-year results of laser treatment for retinopathy of prematurity at a single neonatal intensive care unit

PURPOSE

To present the 2-year results of all patients receiving laser treatment for retinopathy of prematurity (ROP) at a single institution over a 9.5-year period. To establish the frequency of threshold ROP.

METHODS

Consecutive case series. All patients who had laser treatment for ROP at The Royal Women's Hospital, Melbourne, Australia, between January 1992 and July 2001 were prospectively recorded in a database. Their medical charts were retrospectively reviewed. Baseline birthweight, gestational age at birth, timing of treatment, and ROP severity at treatment were recorded. The main outcome measures were visual acuity (significantly reduced or not), anatomic outcome and refractive error at 2 years of age (corrected for the degree of prematurity).

RESULTS

A total of 107 eyes of 57 babies were treated with laser photocoagulation. Four children did not survive for follow-up, and 2-year follow-up data were available for 38 children (67%, 71 treated eyes). Average duration of follow-up was 26 months. Two-year visual acuity was significantly reduced in 12/71 (17%) treated eyes, and 3/38 children (8%) had significantly reduced vision in both eyes. An anatomical outcome of macular fold or worse was observed in 8/71 eyes (11%). Mean 2-year spherical equivalent refractive outcome was only minimally myopic (-0.6 D).

CONCLUSION

Visual, anatomic and refractive outcomes after laser treatment for ROP were favourable, confirming that laser photocoagulation is an effective treatment for severe ROP.

Primary trabeculodysgenesis in association with neonatal Marfan syndrome

We present the clinical and ophthalmological findings in two infants with neonatal Marfan syndrome (nMFS) and primary trabeculodysgenesis (PT). Fibrillin 1 (FBN1) mutations were confirmed in both cases. Numerous eye anomalies have been recognized in infants with nMFS, but PT has not been reported previously. Our report expands the phenotype of nMFS, and highlights the importance of early and careful ophthalmological assessment of these infants.

Primary infantile glaucoma in an Australian population

BACKGROUND

Primary infantile glaucoma presents rarely, but can be responsible for significant visual morbidity. There is little information on the clinical features and visual outcome of a pure population of primary infantile glaucoma, as opposed to a mixed population of primary and secondary glaucoma or combined group of those with trabeculodysgenesis and iridotrabeculodysgenesis.

METHODS

We conducted a retrospective review of children with primary infantile glaucoma seen in south-eastern Australia between 1980 and 2000, using The Royal Children's Hospital ophthalmic diagnostic coding database.

RESULTS

Fifty-one patients with primary infantile glaucoma were identified (83 eyes). This equates to an estimated incidence of approximately 1 in 30,000 births. The mean +/- SD age at presentation was 135 +/- 84 days. 'Burnt-out' disease (megalocornea without raised intraocular pressure) was diagnosed in 10.8%. Goniotomy was the most commonly performed surgical procedure (69.4% of 72 eyes). Surgical success with one or two goniotomies was achieved in 74% of eyes. Visual outcomes at final review were generally good with 61.8% reading 6/12 or better. There were a disproportionately high number of children having a final recorded acuity of <6/60 in the group diagnosed in the first 3 months of life.

CONCLUSIONS

Primary infantile glaucoma is a rare ocular condition in this population that presents at a mean age of 4.4 months. Surgical and visual outcomes are generally favourable.

Investigation of crystallin genes in familial cataract, and report of two disease associated mutations

AIMS

Mutations of seven crystallin genes have been shown to cause familial cataract. The authors aimed to identify disease causing crystallin mutations in paediatric cataract families from south eastern Australia.

METHODS

38 families with autosomal dominant or recessive paediatric cataract were examined. Three large families were studied by linkage analysis. Candidate genes at regions providing significant LOD scores were sequenced. Single stranded conformational polymorphism (SSCP) analysis was used to screen five crystallin genes in the probands, followed by direct sequencing of observed electrophoretic shifts. Mutations predicted to affect the coding sequence were subsequently investigated in the entire pedigree.

RESULTS

A LOD score of 3.72 was obtained at the gamma-crystallin locus in one pedigree. Sequencing revealed a P23T mutation of CRYGD, found to segregate with disease. A splice site mutation at the first base of intron 3 of the CRYBA1/A3 gene segregating with disease was identified by SSCP in another large family. Five polymorphisms were also detected.

CONCLUSIONS

Although mutations in the five crystallin genes comprehensively screened in this study account for 38% of paediatric cataract mutations in the literature, only two causative mutations were detected in 38 pedigrees, suggesting that crystallin mutations are a relatively rare cause of the cataract phenotype in this population.

Hereditary hyperferritinemia-cataract syndrome: prevalence, lens morphology, spectrum of mutations, and clinical presentations

OBJECTIVES

To provide a comprehensive description of the clinical presentations, cataract morphology, and molecular basis of hereditary hyperferritinemia-cataract syndrome (HHCS) in 4 Australian pedigrees and to estimate its prevalence.

METHODS

All known cases of HHCS in southeastern Australia were ascertained. Family members provided a medical history and underwent physical examination, lens photography, and venipuncture for measurement of serum ferritin levels and DNA extraction. Sequence analysis of the iron-responsive element of the ferritin light chain on chromosome 19q13.3-qter was performed.

RESULTS

We investigated 26 affected individuals from 5 Australian pedigrees. Two pedigrees with HHCS ascertained independently were subsequently found to form 1 large kindred carrying the mutation A40G. The minimum estimated prevalence of HHCS is 1/200000. One pedigree had the mutation G32C. Among 2 smaller pedigrees studied, one carried a novel mutation (C39A), and the other was identified through the 2-year-old propositus with cataract but no positive family history. The latter case was shown to be due to a de novo mutation (G32U). All cataracts were highly distinctive in morphology, consisting of slowly progressive flecks, vacuoles, and distinctive crystalline deposits scattered predominantly in the lens cortex but also in the nucleus. Eight of 18 affected individuals examined have required cataract extraction to date. No other identified clinical manifestations of HHCS were delineated.

CONCLUSIONS

Cataract morphology in HHCS is highly distinctive. Longitudinal observation demonstrated slow progression of the cataracts. This study highlights that, although HHCS is an autosomal dominant condition, the diagnosis should be considered even in sporadic cataract of typical morphology. Furthermore, individuals with unexplained hyperferritinemia should be referred for ophthalmological assessment, as the cataract may be asymptomatic but lead to a correct diagnosis of HHCS. Clinical Relevance Progressive cataracts of highly distinctive morphology are an important feature of HHCS. Evaluation for this type of cataract may be of diagnostic value in patients with unexplained hyperferritinemia. Hereditary hyperferritinemia-cataract syndrome can be a cause of cataracts in pediatric patients even in the absence of any positive family history.

Mutations in a novel gene, NHS, cause the pleiotropic effects of Nance-Horan syndrome, including severe congenital cataract, dental anomalies, and mental retardation

Nance-Horan syndrome (NHS) is an X-linked disorder characterized by congenital cataracts, dental anomalies, dysmorphic features, and, in some cases, mental retardation. NHS has been mapped to a 1.3-Mb interval on Xp22.13. We have confirmed the same localization in the original, extended Australian family with NHS and have identified protein-truncating mutations in a novel gene, which we have called "NHS," in five families. The NHS gene encompasses approximately 650 kb of genomic DNA, coding for a 1,630-amino acid putative nuclear protein. NHS orthologs were found in other vertebrates, but no sequence similarity to known genes was identified. The murine developmental expression profile of the NHS gene was studied using in situ hybridization and a mouse line containing a lacZ reporter-gene insertion in the Nhs locus. We found a complex pattern of temporally and spatially regulated expression, which, together with the pleiotropic features of NHS, suggests that this gene has key functions in the regulation of eye, tooth, brain, and craniofacial development.

Aetiology of congenital and paediatric cataract in an Australian population

BACKGROUND/AIM

Paediatric cataract is a major cause of childhood blindness. Several genes associated with congenital and paediatric cataracts have been identified. The aim was to determine the incidence of cataract in a population, the proportion of hereditary cataracts, the mode of inheritance, and the clinical presentation.

METHODS

The Royal Children's Hospital and the Royal Victorian Eye and Ear Hospital have a referral base for almost all paediatric patients with cataracts in south eastern Australia. The database contains cases seen over the past 25 years. The medical histories of these patients were reviewed.

RESULTS

421 patients with paediatric cataract were identified, which gives an estimated incidence of 2.2 per 10,000 births. Of the 342 affected individuals with a negative family history, 50% were diagnosed during the first year of life, and 56/342 (16%) were associated with a recognised systemic disease or syndrome. Unilateral cataract was identified in 178/342 (52%) of sporadic cases. 79 children (from 54 nuclear families) had a positive family history. Of these 54 families, 45 were recruited for clinical examination and DNA collection. Ten nuclear families were subsequently found to be related, resulting in four larger pedigrees. Thus, 39 families have been studied. The mode of inheritance was autosomal dominant in 30 families, X linked in four, autosomal recessive in two, and uncertain in three. In total, 178 affected family members were examined; of these 8% presented with unilateral cataracts and 43% were diagnosed within the first year of life.

CONCLUSIONS

In the paediatric cataract population examined, approximately half of the patients were diagnosed in the first year of life. More than 18% had a positive family history of cataracts. Of patients with hereditary cataracts 8% presented with unilateral involvement. Identification of the genes that cause paediatric and congenital cataract should help clarify the aetiology of some sporadic and unilateral cataracts.

Visual improvement despite radiologically stable disease after treatment with carboplatin in children with progressive low-grade optic/thalamic gliomas

BACKGROUND

The purpose of this study was to examine the clinical and radiologic response to carboplatin by children with progressive optic/thalamic gliomas.

PATIENTS AND METHODS

Between July 1997 and July 1999, 12 consecutive children were treated with monthly carboplatin for progressive optic/thalamic gliomas.

RESULTS

Five children have completed 12 cycles of carboplatin and five children are currently receiving treatment. Two children had progressive disease noted both clinically and radiologically. Nine children have stable radiologic disease and one child has had a partial radiologic response to chemotherapy. Eight children have had regular visual assessments. Four children (three with stable radiology and one with a partial radiologic response) have had improvement in their vision. Three children with radiologically stable disease have had no change in vision. One child has had deterioration in vision despite radiologically stable disease.

CONCLUSIONS

The results suggest that the clinical response of optic/thalamic gliomas to carboplatin, as measured by visual acuity and visual fields, may be better than predicted by radiologic assessment. These data suggest that a prospective clinical study is warranted of the role of carboplatin in children with progressive optic/thalamic gliomas and visual impairment.

Tension pneumo-orbitus and pneumocephalus induced by a nasal oxygen cannula: report on two paediatric cases

The present paper highlights the potential dangers of misplaced nasopharyngeal oxygen cannulae causing secondary pneumo-orbitus and pneumocephalus in two paediatric patients. While this complication is uncommon, early recognition allows prompt and appropriate intervention, with cessation of nasal oxygen, cannula removal, early investigation with computed tomography (CT) head/orbit scan and orbital or cranial decompression, if required. Early CT imaging identifies medial orbital or paranasal sinus fractures, the presence of sinusitis, associated intracranial air and assessment of the degree of orbital or intracranial tension. Antibiotics are not usually required for this type of clean injury unless pre-existing sinusitis is identified. In both cases, direct orbital decompression was performed with excellent results after identification of marked unilateral tense exophthalmos, delayed pupillary reactions to light and ophthalmopegia.