Evidence of predisposing epimutation in retinoblastoma.

Retinoblastoma (RB), which represents the most common childhood eye cancer, is caused by biallelic inactivation of RB1 gene. Promoter hypermethylation is quite frequent in RB tissues but conclusive evidence of soma-wide predisposing epimutations is currently scant. Here, 50 patients who tested negative for RB1 germline sequence alterations were screened for aberrant promoter methylation using methylation-specific MLPA. The assay, performed on blood, identified a sporadic patient with methylation of CpG106, absent in parents' DNA. Bisulfite pyrosequencing accurately quantified CpG methylation in blood DNA (mean ∼49%) and also confirmed the aberration in DNA isolated from oral mucosa although at lower levels (mean ∼34%). Using a tag-SNP, methylation was demonstrated to affect the maternal allele. Real-time qPCR demonstrated RB1 transcriptional silencing. In conclusion, we documented that promoter methylation can act as the first "hit" in Knudson's model. This mosaic epimutation mimics the effect of an inactivating mutation and phenocopies RB onset.

Intra-arterial chemotherapy for retinoblastoma: the dosimetric impact.

PURPOSE: Purposes are (1) to measure main radiation parameters and (2) to propose a method to estimate the absorbed doses of internal organs starting from DAP values. Measuring the exposition of internal organs by repeated irradiations on an anthropomorphic phantom with the same settings used in vivo, we could establish correlations between (1) DAP and the dose recorded by a dosimeter placed along the X-ray beam entrance pathway; (2) the dose recorded by the same dosimeter and the absorbed dose in internal organs. METHODS: Forty-four consecutive patients (16 males, 28 females) (mean age 35.4 months) treated at our institution with IAC (216 procedures: 196 via the ICA and 20 into branches of the ECA) were included in this prospective study. IAC was divided into 5 phases. Fluoroscopic time, DAP, and ESD were measured. RESULTS: The mean DAP was 595 ± 445 cGy cm2 and the mean fluoroscopic time was 540 ± 403 s. ESD was on average 9.59 mGy (range 0.8-165 mGy). The absorbed dose was lower than 12.1 mGy in the left retina (the more exposed organ) in 75% of single treatments and lower than 25 mGy in 95% of treatments. In the cases of 3 and 6 sessions, the left retina of 75% of patients absorbed respectively less than 36.3 and 72.7 mGy, whereas the left retina of 95% of patients received less than 75.2 and 150.4 mGy. Other organs were less exposed. CONCLUSION: This paper describes a method of absorbed dose estimation providing ranges used clinically in a single practice and the basis for further prospective studies.

Transorbital anastomotic pathways between the external and internal carotid systems in children affected by intraocular retinoblastoma.

PURPOSE: It is well known that many anastomoses can join the external carotid system and the ophthalmic artery. However, their frequency has never been reported. Since they can be relevant for interventional radiologists operating in the orbit, we decided to illustrate and determine the frequency of the anastomoses that can be found in children. METHODS: A retrospective study of 443 angiographic procedures (via ophthalmic artery and/or external carotid artery) carried out on 97 children affected by intraocular retinoblastoma was made to investigate the arterial anatomy of 106 orbits. RESULTS: Anastomoses were observed in 44.33 % of orbits. However, their true frequency is likely much higher as the rate of visualization increased up to 91.11 % of orbits when the angiographic study was extended to the external carotid artery. In order of frequency we detected the following anastomoses: lacrimal artery-middle meningeal artery, lacrimal artery-anterior deep temporal artery, ophthalmic artery-middle meningeal artery, ophthalmic artery-facial artery, supraorbital artery-superficial temporal artery, supratrochlear artery-superficial temporal artery, supraorbital artery-middle meningeal artery, dorsal nasal artery-infraorbital artery, supraorbital artery-zygomaticoorbital artery, lacrimal artery-zygomaticoorbital artery. CONCLUSION: When properly searched, anastomoses between the ophthalmic artery and the external carotid artery are almost constant in children. Depending on the clinical scenario, they can represent dangers or valuable alternative routes for collateral circulations and intraarterial chemotherapy.

Two masquerade presentations of retinoblastoma.

Masquerade syndromes are disorders occurring with intraocular inflammation misdiagnosed as uveitis. The underlying causes may be benign or malignant conditions, and one of the most important diagnoses to take into consideration in children is retinoblastoma. We present two cases with uncertain early misdiagnosis whose definite diagnosis eventually was retinoblastoma.

Assessment of early-stage optic nerve invasion in retinoblastoma using high-resolution 1.5 Tesla MRI with surface coils: a multicentre, prospective accuracy study with histopathological correlation.

OBJECTIVES: To assess the accuracy of high-resolution (HR) magnetic resonance imaging (MRI) in diagnosing early-stage optic nerve (ON) invasion in a retinoblastoma cohort. METHODS: This IRB-approved, prospective multicenter study included 95 patients (55 boys, 40 girls; mean age, 29 months). 1.5-T MRI was performed using surface coils before enucleation, including spin-echo unenhanced and contrast-enhanced (CE) T1-weighted sequences (slice thickness, 2 mm; pixel size <0.3 × 0.3 mm(2)). Images were read by five neuroradiologists blinded to histopathologic findings. ROC curves were constructed with AUC assessment using a bootstrap method. RESULTS: Histopathology identified 41 eyes without ON invasion and 25 with prelaminar, 18 with intralaminar and 12 with postlaminar invasion. All but one were postoperatively classified as stage I by the International Retinoblastoma Staging System. The accuracy of CE-T1 sequences in identifying ON invasion was limited (AUC = 0.64; 95 % CI, 0.55 - 0.72) and not confirmed for postlaminar invasion diagnosis (AUC = 0.64; 95 % CI, 0.47 - 0.82); high specificities (range, 0.64 - 1) and negative predictive values (range, 0.81 - 0.97) were confirmed. CONCLUSION: HR-MRI with surface coils is recommended to appropriately select retinoblastoma patients eligible for primary enucleation without the risk of IRSS stage II but cannot substitute for pathology in differentiating the first degrees of ON invasion. KEY POINTS: • HR-MRI excludes advanced optic nerve invasion with high negative predictive value. • HR-MRI accurately selects patients eligible for primary enucleation. • Diagnosis of early stages of optic nerve invasion still relies on pathology. • Several physiological MR patterns may mimic optic nerve invasion.

Identification of Intraorbital Arteries in Pediatric Age by High Resolution Superselective Angiography.

PURPOSE: Angiography is a powerful tool to identify intraorbital arteries. However, the incidence by which these vessels can be identified is unknown. Our purpose was to determine such incidence and which angiographic approach is best for the identification of each artery. METHODS: A retrospective study of 353 angiographic procedures (via ophthalmic artery and/or external carotid artery) carried out on 79 children affected by intraocular retinoblastoma was made to investigate the arterial anatomy in 87 orbits. For each intraorbital artery two parameters were calculated: the angiographic incidence, as the percentage of times a given artery was identified, and the visibility index, as the ratio between the angiographic incidence and the true anatomic incidence. RESULTS: All collaterals of the ophthalmic artery could be spotted. Most of them were identified with a high angiographic incidence; some of them were less easily identified because too thin or because frequently shielded. The visibility index paralleled the angiographic incidence of most arteries. However, the lacrimal and meningolacrimal arteries had a higher visibility index suggesting that their identification was more frequent than the angiographic incidence alone could suggest. Statistical analysis demonstrated that the lacrimal artery and some muscular branches had higher chances to be identified if the angiography of the ophthalmic artery was accompanied by the study of the external carotid system. CONCLUSION: This work provides an objective measure of how powerful angiography is to identify intraorbital arteries as well as useful references for professionals who need to operate in the orbit.

Alternated intra-arterial and intravitreal chemotherapy for advanced intraocular retinoblastoma: preliminary successful results without systemic chemotherapy.

To describe the efficacy of intravitreal chemotherapy (IViC) preceded by intra-arterial chemotherapy (IAC) for the treatment of advanced stage retinoblastoma. This non-comparative interventional case series retrospectively reviewed the medical records of six patients who presented within months of each other with unilateral retinoblastoma, Reese-Ellsworth stage Vb/D of ABC classification in the affected eye. After clinical and ophthalmoscopic evaluation, they underwent MRI to exclude local and CNS dissemination. The IAC was given to treat retinal masses and intravitreal injections to treat vitreous seeding. Patients had received two cycles (six infusions) of IAC, and from six up to ten melphalan injections into the vitreous, with an interval of 7-10 days between them. From one to four intravitreal injections were performed for partial remission or consolidation. No permanent complications of procedures have been reported. All patients underwent to bimonthly MRI examination, during treatment and every 3 months for 1 year after last injection, to exclude orbital dissemination. Successful control (100 %) of tumor masses and vitreous seeds was achieved in all cases at 12 months follow-up. Complications were posterior lens opacity, acute ischemic papillitis, partial CVR thrombosis, hypotonia (case 1), partial vitreous hemorrhage (case 4). No complications appeared in cases 2, 3, 5, and 6. No intraocular or orbital tumor recurrence or retinoblastoma metastases (follow-up range, 12-33 months) were observed. Sequential IAC and intravitreal melphalan for advanced retinoblastoma allowed to provide retinal and vitreous seed control.

Massive anterior chamber involvement after intra-arterial chemotherapy for retinoblastoma: ultrasound biomicroscopy and histopathology.

This case report highlights the usefulness of Ultrasound Biomicroscopy (UBM) in a case of retinoblastoma which showed massive anterior chamber involvement after treatment with intra-arterial chemotherapy. UBM was used to document tumour pseudohypopion, cells in the aqueous humor, implanted clusters of cells on the corneal endothelium, iris nodules, lens capsule deposits and ciliary body invasion. The UBM data, compared with the histopathologic analysis, performed on eye tissue, after enucleation of the affected eye, revealed a significant concordance. UBM may represent an important diagnostic tool in retinoblastoma, when the decision about enucleation of the eye must be made in the absence of histopathologic data.

Unusual anterior and posterior segment features of coats disease.

PURPOSE: To report the clinical course and management of unusual anterior and posterior segment features of Coats disease and their relation to the age of the patients to increase the awareness towards these rare clinical features rarely described in the current literature. METHODS: A retrospective descriptive review of 45 eyes of 45 patients affected by Coats disease was conducted at the Retinoblastoma Referral Center and Ophthalmology Unit of the University of Siena in Italy analyzing data from 2000 to 2022. Medical records and images were revised to find some cases presenting unusual anterior and posterior segment features in patients affected by Coats disease.We identified therefore 4 unusual clinical conditions: retinal macrocysts, anterior chamber cholesterolosis, fovea-sparing Coats disease and secondary vasoproliferative tumor. RESULTS: Two patients presented with retinal macrocyst (2/45 = 4.4%), one with anterior chamber cholesterolosis (1/45 = 2.2%), two with fovea sparing Coats disease (2/45 = 4.4%) and one with vasoproliferative tumor associated (1/45 = 2.2%) for a total of six (6/45 = 13.3%) patients manifesting unusual anterior or posterior segment features in Coats disease. CONCLUSION: Unusual anterior and posterior segment features of Coats disease such as retinal macrocyst and anterior chamber cholesterolosis have been more frequently reported in younger children while fovea-sparing and vasoproliferative tumors have been more commonly described in older patients. Age is then a strong prognostic marker which allows to distinguish two different phenotypes of Coats disease: patients younger and older than 3 years old with more aggressive and milder phenotype respectively.

MR Imaging of Adverse Effects and Ocular Growth Decline after Selective Intra-Arterial Chemotherapy for Retinoblastoma.

This retrospective multicenter study examines therapy-induced orbital and ocular MRI findings in retinoblastoma patients following selective intra-arterial chemotherapy (SIAC) and quantifies the impact of SIAC on ocular and optic nerve growth. Patients were selected based on medical chart review, with inclusion criteria requiring the availability of posttreatment MR imaging encompassing T2-weighted and T1-weighted images (pre- and post-intravenous gadolinium administration). Qualitative features and quantitative measurements were independently scored by experienced radiologists, with deep learning segmentation aiding total eye volume assessment. Eyes were categorized into three groups: eyes receiving SIAC (Rb-SIAC), eyes treated with other eye-saving methods (Rb-control), and healthy eyes. The most prevalent adverse effects post-SIAC were inflammatory and vascular features, with therapy-induced contrast enhancement observed in the intraorbital optic nerve segment in 6% of patients. Quantitative analysis revealed significant growth arrest in Rb-SIAC eyes, particularly when treatment commenced ≤ 12 months of age. Optic nerve atrophy was a significant complication in Rb-SIAC eyes. In conclusion, this study highlights the vascular and inflammatory adverse effects observed post-SIAC in retinoblastoma patients and demonstrates a negative impact on eye and optic nerve growth, particularly in children treated ≤ 12 months of age, providing crucial insights for clinical management and future research.

Bilateral retinoblastoma: clinical presentation, management and treatment.

Management of retinoblastoma (Rb), the most common intraocular malignant tumor in childhood, is tailored to each individual case and based on the overall situation. We present a case of bilateral Rbs in a 4-month-old girl, referred to our center for bilateral leukocoria. In the right eye, the optic disc was partially visible, and three large foci of retinoblastoma were noted adjective in the vitreous cavity with satellite retinal detachment. The macula was obscured by the tumors. The tumor was therefore classified as group D (International classification of retinoblastoma), and thus underwent intravenous chemotherapy with the standard three-agent protocol of ifosfamide, carboplatin and etoposide (ICE protocol) delivered monthly for six cycles, regressing with a type I calcified pattern. The left eye presented three multifocal yellow-white retinal masses, with a total retinal detachment, and secondary glaucoma. The lesions were classified as group E and, therefore, taking the results obtained by Shields et al. in group E tumors into consideration, underwent enucleation. This case clearly shows that this cancer is curable if detected at a stage in which it is still contained within the retina, subretinal space or vitreous, and that the management of Rb relies on an experienced team of ocular oncologists, pediatricians and pediatric ophthalmologists working together for the single goal of saving the child's life.

Corrigendum: Spondyloocular syndrome: A novel XYLT2 variant with description of the neonatal phenotype.

[This corrects the article DOI: 10.3389/fgene.2021.761264.].

Trilateral retinoblastoma: neuroimaging characteristics and value of routine brain screening on admission.

Trilateral retinoblastoma (TRb) is a rare disease associating intraocular retinoblastoma with intracranial primitive neuroectodermal tumor. Treatment is difficult and prognosis is poor. This multicenter study evaluates clinical findings and MR imaging characteristics of associated intracranial tumors in Rb patients. Clinical data of 17 patients (16 TRb and 1 quadrilateral Rb patients) included time intervals between Rb and TRb diagnosis and presence of baseline brain-imaging (BBI). Two reviewers reviewed all images individually and one reviewer per center evaluated their images. Consensus was reached during a joint scoring session. Studies were reviewed for tumor location, size and imaging characteristics (signal intensity (SI) on T1- and T2-weighted images, enhancement pattern and cystic appearance). Of 18 intracranial tumors, 78 % were located in the pineal gland and 22 % suprasellar. All tumors showed well-defined borders with mostly heterogenous enhancement (72 %) and isointense SI on T1- (78 %) and T2-weighted images (72 %) compared to gray matter. The majority of pineal TRbs showed a cystic component (57 %). TRb detected synchronously with the intraocular tumors on BBI (n = 7) were significantly smaller (P = 0.02), and mainly asymptomatic than TRb detected later on (n = 10). Overall, 5-year-survival of TRb patients detected on BBI was 67 % (95 % CI 29-100 %) compared to 11 % (95 % CI 0-32 %) for the group with delayed diagnosis. TRb mainly develops in the pineal gland and frequently presents with a cystic appearance that could be misinterpreted as benign pineal cysts. Routine BBI in all newly diagnosed Rb patients can detect TRb at a subclinical stage.

Analysis of aqueous humour proteins in patients with retinoblastoma.

BACKGROUND: To investigate aqueous humour protein composition from retinoblastoma patients. DESIGN: Prospective, hospital-based study. PARTICIPANTS: Eighteen retinoblastoma patients (Reese-Ellsworth stage V or ABC classification group E RB) undergoing ocular enucleation, and 10 normal subjects undergoing cataract surgery. Five of 18 patients presented with associated secondary glaucoma whereas 13 had no secondary glaucoma; 5 of 13 patients with no secondary glaucoma received chemotherapeutical treatment with melphalan. METHODS: Aqueous humour samples were collected by limbal paracentesis of the anterior chamber after ocular enucleation in patients and after the stab peripheral corneal incision in controls. Total protein concentration according to Bradford method and sodium dodecyl sulphate-polyacrylamide gel electrophoresis of the samples were performed. MAIN OUTCOME MEASURE: Aqueous humour protein concentration. RESULTS: Aqueous humour protein concentration was significantly higher in retinoblastoma patients than controls (P < 0.01); patients with secondary glaucoma presented the highest values (P < 0.05 vs. controls); patients treated with melphalan presented a significant decrease (P < 0.01) versus non-treated; controls did not significantly differ from treated patients. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis pattern in retinoblastoma patients who did not receive any treatment was very different either from treated or from controls. CONCLUSION: This study represents a preliminary step towards a more accurate two dimensional electrophoresis (2DE) pattern, which will be combined with mass spectrometry analysis to clarify the potential role of specific proteins in tumour development and progression; although these results suggest that aqueous humour protein pattern in retinoblastoma is characteristic, several aspects of the study are still under investigation.

Very late orbital recurrence of choroidal melanoma four decades post enucleation.

Orbital recurrence of malignant choroidal melanoma is quite uncommon, occurring in about 3% of patients undergoing enucleation for large tumors. Orbital recurrences after more than 10 years from enucleation are even rarer. In literature, only few reports described orbital recurrence that occurred between 10 and 40 years after primary diagnosis. Herein we report a very late choroidal melanoma recurrence, 40 years post enucleation, of a 52 year-old female who had undergone left enucleation at the age of 12. She presented to our clinic for consultation in 2017, complaining of difficulty to contain the prosthesis, as well as, presence of small pigmented palpable nodules inferiorly in her anophthalmic socket. The patient was not aware of the medical condition which had lead to the enucleation. We requested her medical reports and detailed history through her family. We realized after reviewing her charts 40 years back, that her enucleation was due to malignant choroidal melanoma (CMM). Full screening was performed. After magnetic resonance imaging (MRI), that showed the presence of nodular masses in the anophthalmic socket, an excisional biopsy was performed. Histopathology confirmed the diagnosis of CMM (epithelioid and spindle cell type), supporting the hypothesis that residual melanoma cells may remain clinically dormant for long periods, even for decades. A literature review was performed in order to review similar cases and to understand and discuss multiple factors, which may explain this extremely delayed recurrence. To the best of our knowledge, this is the third case to be reported in the literature.

Novel retinal finding in a patient with 4q12 deletion.

BACKGROUND: Chromosome 4q deletions are rare disorders phenotypically characterized by several features. The most commonly described ocular abnormalities include unilateral microphthalmia with bilateral colobomata, blue sclerae with pigmented retinal clumps, hypermetropia, and a divergent squint. PURPOSE: To report a case of 4q12 deletion with a singular retinal feature. MATERIALS AND METHODS: Case report. RESULTS: A 20-year-old Caucasian female with a history of poliosis, progressive appearance of small areas of skin depigmentation along trunk and limbs since birth and diagnosis of learning deficit was referred for a complete ocular examination. The genetic counseling showed microdeletion in the 4q12 region. An audiometric test was performed, showing a progressive bilateral neurosensorial hypoacusia. Ocular examination showed the presence of multifocal, tiny, whitish deposits in the posterior pole. Multimodal imaging defined the lesions as small elevations of the retinal pigment epithelium with slight hyper-autofluorescence and staining in the late phase of fluoresceine angiography (FA). Visual acuity was 20/20. The retinal findings did not change during the three-month follow-up. CONCLUSIONS: Although the findings herein reported have never been described before in patients affected by 4q12 mutations, we do not exclude that they could represent a manifestation of the peculiar genetic asset of the patient, related to dysfunction in pigment epithelium/neuroretinal metabolic activity.

p53 Arg72Pro and MDM2 309 SNPs in hereditary retinoblastoma.

The tumor suppressor p53 and its negative regulator MDM2 have crucial roles in a variety of cellular functions such as the control of the cell cycle, senescence, genome stability and apoptosis, and are frequently deregulated in carcinogenesis. Previous studies have highlighted the contribution of the common functional polymorphisms p53 p.Arg72Pro and MDM2 309SNP to the risk of both common cancers and Li-Fraumeni syndrome. Their possible role in retinoblastoma has recently been addressed by Castéra et al, who however only studied the MDM2 309SNP. Here, for the first time, we analyzed both single nucleotide polymorphisms (SNPs) in a case-control study of 111 Italian hereditary retinoblastoma patients. We found a significant association of the p53 Pro/Pro genotype with the disease (odds ratio=3.58, P=0.002). The MDM2 309SNP showed a weak negative association of allele G that deserves further investigation. These findings further support the hypothesis that genetic variability of the p53 pathway contributes to the individual susceptibility to retinoblastoma, as shown for Li-Fraumeni syndrome and a variety of non-hereditary cancers.

The Addition of Topotecan to Melphalan in the Treatment of Retinoblastoma with Intra-arterial Chemotherapy.

PURPOSE: To evaluate the effect of adding topotecan to melphalan for the treatment of retinoblastoma using intra-arterial chemotherapy (IAC). DESIGN: Single-center, consecutive case series. PARTICIPANTS: All eyes treated with IAC at the University of Siena, Siena, Italy, from 2008 to 2019. METHODS: Eyes were treated via IAC with either melphalan monotherapy or melphalan plus topotecan. The characteristics and outcomes of these 2 groups were compared. MAIN OUTCOME MEASURES: The main outcome measure was globe salvage rate. Additionally, a complete summary of all adverse events for all eyes was compared between groups and included local, regional, and systemic events causing both transient and permanent effects. RESULTS: A total of 193 patients and 208 eyes were treated with IAC between April 2008 and October 2019. Melphalan alone (MA) was used to treat 44 patients and 50 eyes for a total of 191 procedures. The combination of melphalan plus topotecan (MPT) was used to treat 149 patients and 158 eyes for a total of 780 procedures. Groups were similar in terms of age at presentation. The MPT group included more advanced eyes (P < 0.001) and had shorter follow-up time (mean 47 vs. 120 months in the MA group, P < 0.001). The MPT group required less laser and cryotherapy after treatment (32% of eyes vs. 50% of eyes in the MA group, P < 0.001); there was no other difference in the number of adjuvant treatments required between groups. There was no difference in the number of acute adverse events, both systemic and local, between groups. There was no difference in the number of transient or permanent intraocular side effects between groups. Kaplan-Meier survival analysis estimated a better globe salvage rate in the MPT group (66%) compared with the MA group (58%, P = 0.05). CONCLUSIONS: In this case series, the addition of topotecan to melphalan did not alter the IAC side effect profile and may contribute to improved globe salvage.

Fovea-sparing coats disease: A rare clinical entity.

PURPOSE: To evaluate the rarity, clinical features and management of Coats disease characterized by fovea-sparing enhancing the importance of pediatric retinal screening and early management to maintain a good visual acuity. METHODS: Retrospective analysis of approximately 40 patients affected by Coats disease between 2000 and 2020 at the Retinoblastoma Referral Center and Ophthalmology unit of the University of Siena in Italy. RESULTS: Two patients with fovea sparing Coats disease were included. Both presented an extrafoveal Coats disease (stage 2A by Shields classification) when they were 5 and 6 years old respectively.They had no anterior findings and a presenting visual acuity of 20/20 reflecting the early stage and a milder phenotype of the disease which are indeed more likely to be found in patients older than 3 years at presentation.Both presented telangiectasia and retinal exudation in the affected eye. Standard Argon laser photocoagulation and subsequently Cryotherapy were performed in the telangiectatic retinal periphery of both patients obtaining an excellent control and regression of the disease. CONCLUSIONS: Careful pediatric retinal screening and early management are crucial to ensure a good visual prognosis in such an early feature of Coats disease as fovea sparing since this condition unfortunately tends to recall the physician's attention in more advanced stages.Due to the extremely poor number of articles regarding such a rare feature of Coats disease like fovea sparing, we report our experience.

Bilateral retinoblastoma and osteogenesis imperfecta, a very rare association: Two cases.

INTRODUCTION: This case report presents two patients affected by a very rare association of bilateral retinoblastoma and osteogenesis imperfecta. CASE REPORT: Two Caucasian males with familial history and clinical signs of osteogenesis imperfecta came to our attention for bilateral leukocoria. The ocular fundus examination revealed bilateral retinoblastoma. Proper therapies were dispensed in order to achieve full regression. Genetic counseling was performed. DISCUSSION: The primary role of genetics in retinoblastoma pathogenesis in widely known, and different genes have been identified. Osteogenesis imperfecta is a rare connective tissue disorders, caused by mutated genes encoding for collagen. The single gene defect in osteogenesis imperfecta type VI is Serpin Family F Member 1 (SERPINF1), a neurotrophic factor for the neuronal differentiation in retinoblastoma cells. The association of bilateral retinoblastoma and osteogenesis imperfecta could be the result of the mutation of a single gene playing a role in a hypothetical common pathway.