Retinoblastoma (RB) is an ocular tumor of the pediatric age caused by biallelic inactivation of the RB1 gene (13q14). About 10% of cases are due to gross-sized molecular deletions. The deletions can involve the surrounding genes delineating a contiguous gene syndrome characterized by RB, developmental anomalies, and peculiar facial dysmorphisms. Overlapping deletions previously found by traditional and/or molecular cytogenetic analysis allowed to define some critical regions for intellectual disability (ID) and multiple congenital anomalies, with key candidate genes. In the present study, using array-CGH, we characterized seven new patients with interstitial 13q deletion involving RB1. Among these cases, three patients with medium or large 13q deletions did not present psychomotor delay. This allowed defining a minimal critical region for ID that excludes the previously suggested candidate genes (HTR2A, NUFIP1, PCDH8, and PCDH17). The region contains 36 genes including NBEA, which emerged as the candidate gene associated with developmental delay. In addition, MAB21L1, DCLK1, EXOSC8, and SPART haploinsufficiency might contribute to the observed impaired neurodevelopmental phenotype. In conclusion, this study adds important novelties to the 13q deletion syndrome, although further studies are needed to better characterize the contribution of different genes and to understand how the haploinsufficiency of this region can determine ID.

BACKGROUND: The intra-arterial chemotherapy (IAC) is increasingly used as a first-line therapy for retinoblastoma. The IAC has proved to be relatively safe. However, many local side effects of IAC have been described.
METHODS: This case report describes a local side effect presenting as proptosis and myositis with vascular access difficulty of the middle meningeal artery, in a 2-year-old male with left eye diffuse multifocal stage Vb retinoblastoma complicated with retinal detachment.
CONCLUSIONS: IAC is assured to provide as efficient results in eliminating the tumor as the systemic chemotherapy, without causing the systemic side effects. It has become an alternative to systemic chemotherapy. A better understanding of the local side effects is required.

13q33-q34 microdeletions are rare chromosomal aberrations associated with a high risk of developmental disability, facial dysmorphism, cardiac defects and other malformation of organs. It is necessary to collect and report evidence of this rare chromosome mutation to improve the prognosis of this rare disease.
We report a patient harboring an 11.56 Mb microdeletion at 13q33.1-34 region, which contains about 30 OMIM genes. Besides the common clinical manifestations such as facial dysmorphism, developmental delay, intellectual disability, epilepsy, and congenital heart disease, she also suffered from a reduced anogenital distance, hematuria and left renal hypoplasia. Most related cases were characterized by facial deformity and heart defects, but there were few reports on renal malformation, especially regarding renal hypoplasia with hematuria.
We have reported a patient suffering from a reduced anogenital distance, hematuria and left renal hypoplasia. A de novo 11.56 Mb deletion ranging from 13q33.1 to 13q34 (Chr13:103542220-115,106,996) was found by SNP-array analysis. It might be the first time for hematuria and renal hypoplasia to be reported as symptoms of 13q33-q34 deletion syndrome Neurodevelopmental disability, heart defects and urogenital/anorectal anomalies may be resulted from common or overlapping regions of deletion in chromosome bands 13q33.1-q34 and may share a common molecular mechanism.

13q syndrome is a chromosomal abnormality in which there is a pathognomic deletion of the genetic material on the long arm (q) of chromosome 13. Phenotypes of this syndrome are variable depending on the location of the deleted segment. The main manifestations of the syndrome include mental retardation, craniofacial dysmorphism, and increased susceptibility to tumors. We report a unique case of recurrent sporadic bilateral retinoblastoma (Rb) in a four-year-old boy carrying 13q (q12q14) interstitial deletion, which was treated successfully via enucleation and chemotherapy. Where most patients with familial Rb receive a single mutated Rb1 allele as the \'first hit\', a small number of patients encounter interstitial deletion of the long arm of chromosome 13, resulting in the loss of the tumor suppressor Rb1 gene and presenting as sporadic cases.

We report a rare co-occurrence of intestinal malrotation and Hirschsprung\'s disease (HSCR) in a male neonate with a large 38.8 Mb interstitial deletion of chromosome 13 extending from q21.31 to q33.1 including the EDNRB gene, who presented with craniofacial dysmorphic features and central nervous system malformations. The loss of EDNRB gene in addition to bilateral hearing loss and HSCR suggested an additional diagnosis of Waardenburg-Shah\'s syndrome. This case highlights the fact that prior knowledge of this rare association in infants with 13q deletion syndrome would enable early diagnosis and prompt interventions to prevent gastrointestinal complications.

Patients with deletion of chromosome 13 present with variable clinical features, and the correlation between phenotype and genomic aberration is not well established in the literature, mainly due to variable sizes of the deleted segments and inaccuracy of breakpoint mapping. In order to improve the genotype-phenotype correlation, we obtained clinical and cytogenomic data from 5 Brazilian patients with different chromosome 13 deletions characterized by G-banding and array techniques. Breakpoints were nonrecurrent, with deletion sizes ranging from 3.8 to 43.3 Mb. Our patients showed some classic features associated with 13q deletion, independent of the location and size of the deletion: hypotonia, growth delay, psychomotor developmental delay, microcephaly, central nervous system anomalies, and minor facial dysmorphism as well as urogenital and limb abnormalities. Comparisons between the literature and our patients\' data allowed us to narrow the critical regions that were previously reported for microphthalmia and urogenital abnormalities, indicating that gene haploinsufficiency of ARHGEF7, PCDH9 and DIAPH3, of MIR17HG and GPC6, and of EFNB2 may contribute to microcephaly, cardiovascular disease, and urogenital abnormalities, respectively. The knowledge about genes involved in the phenotypic features found in 13q deletion patients may help us to understand how the genes interact and contribute to their clinical phenotype, improving the patient\'s clinical follow-up.

The 13q deletion syndrome is a rare genetic disorder caused by structural and functional monosomy of chromosome 13. On 13q34, which is the terminal of the long arm, causative genes of coagulation factors VII and X (FVII and FX) are mapped. Patients with a combination of FVII and FX deficiencies are extremely rare and there have been few articles about perioperative coagulation support for such patients. Herein, we report on a case of bilateral cleft lip and palate accompanied by 13q deletion syndrome with deficiencies of FVII and FX. The chromosomal investigation indicated 46, XX, del(13)(q33) by G-banding. Prothrombin time and activated partial thromboplastin time were found to be 21.0 seconds (sec) (prothrombin time-international normalized ratio 1.76) and 41.6 sec (normal range; 23.9 - 39.7 sec), respectively. The activities of coagulation FVII and FX were 22% and 36%, respectively. A two-stage cheiloplasty was performed at 4 and 7 months of age followed by a palatoplasty at 1 year and 6 months. Tranexamic acid was given intravenously three times a day for three days after each surgery. There were no adverse events such as bleeding from the oral or nasal cavities and healing of the surgical wound was good without dehiscence.

BACKGROUND: The 13q deletion syndrome is a rare chromosome disorder associated with wide phenotypic spectrum, which is related to size and location of the deleted region and includes intellectual disability, growth retardation, craniofacial dysmorphisms, congenital malformations, and increased risk of retinoblastoma.
METHODS: Here, we report on a teenage boy with a mild phenotype characterized by obesity, hyperactivity, dysphagia, dysgraphia, sleep disturbance, and minor dysmorphic features (round face, bushy eyebrows, and stubby hands). Array Comparative Genomic Hybridization on blood identified a mosaic 13q14.13-13q31.1 deletion, with a mosaicism rate around 40%, which was confirmed by quantitative PCR and interphase Fluorescent In Situ Hybridization (iFISH) on both blood genomic DNA and cultured/uncultured blood lymphocytes, respectively. Conversely, karyotype analysis on blood estimated a mosaicism rate of 24% and iFISH on buccal smears revealed a borderline value of 0.4%, suggesting the absence of 13q deletion in this cell line.
CONCLUSIONS: The comparison with previous patients carrying similar deletions informed that the proband clinical presentation is the mildest reported to date, thus supporting the burden of mosaicism in modulating the phenotype also in case of large chromosomal rearrangements. Characterization of further cases by in-depth mosaicism rate in tissues with different embryonic origins might contribute in the future to a better definition of genotype-phenotype correlation, including tumor risk.

A total of 5-10% of patients with retinoblastoma (RB) harbor deletion of the long arm (q) chromosome 13 (13q-). The treatment-related toxicities in this population have not been described.
Sixty-eight RB patients on a single institutional protocol (RET5) from 2005 to 2010 were reviewed. Genetic screening identified 11 patients (seven female) with 13q-. Patients with early (Reese-Ellsworth [R-E] group I-III) disease (6/23 with 13q-) received eight courses of vincristine/carboplatin (VC). Patients with advanced (R-E group IV-V) bilateral disease (2/27 with 13q-) received two courses of vincristine/topotecan (VT) followed by nine courses of alternating VT/VC. Patients undergoing upfront enucleation received histopathology-based chemotherapy: intermediate risk (2/8 with 13q-) or high risk (1/10 with 13q-). Dose reductions were mandated for >7 day delay in two consecutive courses following hematologic toxicity. Grades 3 and 4 hematologic, infectious, and gastrointestinal toxicities were compared between RET5 patients with and without 13q-.
Demographics were similar between groups. When present, prolonged neutropenia (median 7 days, range 0-14 days) delayed chemotherapy and resulted in more frequent dose reductions among 13q- patients (5/11) than non-13q- patients (4/57) (P < 0.01). GI toxicity was similar between groups (5/11 13q- vs. 13/57 non-13q-; P = 0.14), but halted chemotherapy in one 13q- patient. Infectious complications and disease outcomes were similar between groups. At follow-up, all patients are alive (median 6.1 years, range 7.6 months-9.5 years).
13q- RB patients had a higher incidence of neutropenia requiring chemotherapy dose reductions, but did not have increased treatment failure.

Retinoblastoma is the most common primary intraocular malignancy of childhood. It typically presents with leukocoria or strabismus. In later stages of the disease, the child may exhibit proptosis, buphthalmos, or hypopyon. The pathognomonic molecular aberration is a loss of function mutation in the RB1 gene on chromosome 13q. The degree of tumor involvement within the eye is defined by its group. Grouping was historically done with Reese-Ellsworth System. Recent therapeutic advances have led to the development of a new grouping system, the International Classification of Retinoblastoma (ICRB). In cases of extraocular extension and metastatic disease, the degree of tumor involvement outside of the eye is defined by its stage. Retinoblastoma is staged using the International Retinoblastoma Staging System (IRSS). Children with intraocular retinoblastoma have an excellent overall and ocular survival. In order to avoid the morbidity of enucleation and external beam radiation, treatments for isolated intraocular retinoblastoma have progressively moved toward targeted local modalities. Patients with extraocular involvement, such as those with trilateral retinoblastoma, have a poorer prognosis. The majority of these higher stage patients are now able to be cured with combination chemotherapy.