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Background: Factor VII deficiency is rare inherited bleeding disorders, have been identified in the Factor VII gene located on chromosome 13 with very few cases reported. Factor VII deficiency was first described by Alexander et al. in 1951.The disorder has also been known as Alexander's disease. It is the rare inherited bleeding disorders’ with an estimated incidence of 1 case per 3,00,000 to 5,00,000 individuals. Objective and method: We did a case report and literature review for deficiency of coagulation factors VII was found in a 4 years patient who had chromosomal aberration 13q deletion syndrome (46, XX, del 13q32-13q33). This loci involved in synthesis or constitution of factor VII. Results: A review of the gene map of chromosome 13 indicated that Factors VII and X are coded on the long arm of chromosome 13, within the deleted region. Conclusion: Congenital Factor VII deficiency is a rare cause of bleeding disorder, which should be suspected in a bleeding child presenting in infancy when platelets and aPTT are normal with abnormal PT. Congenital Factor VII deficiency association with 46, XX, del (13q32– 13q33) syndrome is very rare disorder and further cases should be reported to know the outcome and the risk of complication in such a cases.

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 Patients with 13q-syndrome are at risk of retinoblastoma when the RB1 gene, located in the chromosomal band 13q14.2, is deleted. This syndrome is frequently associated with congenital malformations and developmental delay, although these signs could be mild. Mosaic 13q-deletion patients have been previously reported in the literature; their phenotype is variable, and they may not be recognized. Case presentation Retinoblastoma diagnosed in a child with 13q-mosaicism confirmed in blood, oral mucosa, healthy retina and retinoblastoma. A second RB1 hit is present exclusively in the retinoblastoma sample (RB1 c.958C>T p.Arg320Ter). Other detected molecular events in retinoblastoma are 6p12.3pter gain and 6q25.3qter loss. Clinical examination is unremarkable except for clinodactyly of the right fifth finger. Discussion and conclusions We describe a case of mosaic 13q deletion syndrome affected by retinoblastoma. Molecular data obtained from the tumor analysis are similar to previous data available about this malignancy. High clinical suspicion is essential for an adequate diagnosis of mosaic cases.

The 13q deletion syndrome is a rare chromosomal disorder caused by loss of the long arm of chromosome 13, and usually entails developmental delay, intellectual disability, behavioral problems and distinctive facial features. In this study, we successfully generated a human iPSC line (MUi015-A) from skin fibroblasts of a patient who had large deletion of chromosome 13, del(13)(q14q22). The MUi015-A line exhibited embryonic stem cell characteristics with consistent pluripotency marker expression and the capability of differentiating into three germ layers. The cell line provides a good tool in studying pathophysiology of the tumors, drug testing and gene therapy.

The methylenetetrahydrofolate reductase (MTHFR) gene encodes an enzyme called MTHFR involved in the processes of DNA methylation and chromosome segregation. MTHFR polymorphisms are associated with DNA methylation disorders including congenital malformations and chromosomal abnormalities, and various obstetrical complications such as miscarriage, fetal growth retardation, preeclampsia, preterm labor, etc. Herein, we have reported a patient with compound heterozygous MTHFR polymorphisms in whom different type of adverse pregnancy outcomes (1. blighted ovum, 2. preterm delivery, and 3. pregnancy with a fetus having anencephaly and meningocele going together with 46, XX, del (13) (q22)) were observed in her previous 3 pregnancies. She was referred to our hospital during her third pregnancy for prenatal diagnosis. Her fourth baby was born healthy at 37th gestational week after having necessary precautions. Low dose low molecular weight heparin and low-dose acetylsalicylic acid were added to patient-specific management protocol immediately after the confirmation of her fourth pregnancy. In conclusion, DNA methylation enzyme pathway disorders are associated with adverse gestational outcomes., Metilentetrahidrofolat redüktaz (MTHFR) geni, DNA metilasyonu ve kromozom ayrılması süreçlerinde yer alan MTHFRadı verilen bir enzimi kodlar. MTHFR polimorfizmleri, konjenital malformasyonlar ve kromozomal anomalilerini içerenDNA metilasyon bozuklukları ve abortus, fetal büyüme geriliği, preeklampsi, erken doğum, vb. gibi çeşitli obstetrikkomplikasyonlarla ilişkilidir. Çalışmamızda compound heterozigot mutasyonu olan ve önceki üç gebeliğinde kötü obstetriksonuçları (1. blighted ovum, 2. preterm doğum ve 3. anensefali ve meningoseli, 46, XX, del (13) (q22) ile birlikte seyredenbir fetus ile gebelik) olan bir hasta değerlendirilmiştir. Hastanın dördüncü bebeği gerekli önlemleri aldıktan sonra 37.gebelik haftasında sağlıklı doğdu. Dördüncü gebeliğin doğrulanması takiben düşük doz düşük moleküler ağırlıklı heparinve düşük doz asetilsalisilik asit hastaya özgü yönetim protokolü çerçevesinde başlandı. Sonuç olarak, DNA metilasyonenzimi yolu bozuklukları, olumsuz gebelik sonuçları ile ilişkilidir.

Background Retinoblastoma is a malignancy of the eye in children characterized by biallelic inactivation of the retinoblastoma 1 gene (RB1), located at chromosome 13q14.2. Children with interstitial chromosome 13q deletions that include the RB1 gene show a predisposition to develop retinoblastoma and variable other features. Large 13q deletions with severe clinical phenotype are nearly always the result of a de novo mutation, i.e. the pathogenic alteration is not detected in parents. This results in a low risk for siblings to develop 13q deletion syndrome. Result Here, we describe a patient with profound muscle hypotonia, severe developmental delay and bilateral retinoblastoma carrying a large deletion in 13q13.3q14 with the size of 16 Mb, involving the RB1 gene. Neither parent showed retinoblastoma, muscle hypotonia or developmental delay. Chromosome analysis and Fluorescence in situ hybridization (FISH) showed a balanced complex chromosomal rearrangement (CCR) between chromosome 12 and 13 [ins(12;13)(q21.2;q12.3q14.3)] and an additional balanced translocation of chromosome 7 and 15 [t(7;15)(q31.2;q25.3)] in the healthy father. Malsegregation of the paternal insertional translocation involving chromosome 12 and 13 resulted in a 13q deletion syndrome of the child [46,XY,ins(12;13)(q21.2;q12.3q14.3)]. Conclusion Balanced translocations in parents are a rare cause of de novo RB1 deletions in offspring. This case report emphasizes the need for parental chromosomal analysis and FISH in parents of children diagnosed with 13q deletion syndrome or large RB1 gene deletions to precisely determine the recurrence risk in siblings. Guidelines for genetic testing should be revised accordingly.

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.

Diabetes mellitus is a multifactorial disease caused by a complex interaction of environmental and genetic factors. Some diabetes mellitus cases, however, are caused by a limited number of mutant genes. Chromosome 13q deletion syndrome, an extremely rare genetic disorder, is caused by structural and functional monosomy of the 13q chromosomal region. We report the case of a 38-year-old Japanese man with Chr13q deletion (a mosaic pattern with heterozygous ring Chr13q) who developed diabetes mellitus. Early-onset diabetes mellitus developed in this patient because of insulin resistance and a lack of adequate insulin secretion. Microarray analysis identified a 4.8-Mb deletion of distal Chr13q, leading to a copy number loss of 40 genes. Among those genes, the insulin receptor substrate 2 gene (IRS2) was the most likely causative candidate for the development of diabetes mellitus in this patient, based on the model of IRS2 knockout mice, which have abnormal glucose and insulin homeostasis closely resembling the human diabetes phenotype. These data provide important information regarding the contribution of a microdeletion of Chr13q, including in IRS2, to the pathogenesis of diabetes mellitus in humans.

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.

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.

Germline partial chromosomal deletions of the entire RB1 gene (13q deletions), account for 6% of the RB1 mutational spectrum. The authors report the rare case of one patient with suspected bilateral iris heterochromia who actually had iris hypoplasia (often masquerading as heterochromia) and bilateral retinoblastoma, due to 13q deletion syndrome . [ J Pediatr Ophthalmol . 2018;55:e10–e13.]

Orbeli syndrome, or 13q deletion syndrome, is a rare condition caused by a distal deletion in the long arm of chromosome 13. The syndrome is characterized by severe physical malformations and developmental delays and has been associated with numerous ocular manifestations. We report the case of a 10-year-old boy with 13q deletion syndrome, who was evaluated for impaired vision and found to have bilateral retinal pigmentary changes resembling those seen in retinitis pigmentosa. There has only been one other case of retinal pigment variation in association with 13q deletion syndrome; however, this represents the first case of bilateral symmetric retinal pigmentary changes with corresponding rod and cone dysfunction on electroretinography.

We report on a child with a de novo deletion of approximately 12 Mb detected through array comparative genomic hybridization (CGH). The deletion involved chromosome bands 13q12.3 to 13q14.11 and determined the loss of ≥ 50 genes. A second deletion on chromosome 12p11.3p11.22 of 43-167 kb, including about 12 genes, was unlikely of clinical relevance because inherited from the asymptomatic father. The child had developmental delay, dysmorphisms and many features reminiscent of ataxia-telangiectasia (A-T), as cerebellar ataxia, oculocutaneus telangiectasia and recurrent upper airway infections. Atraumatic fractures of the metatarsus were noted. Moreover, this is a rare case of 13q deletion syndrome associated with peripheral blood white cells radiosensitivity to bleomycin, reminiscent of what previously reported on X-ray hypersensitivity of fibroblasts from patients with alterations of this chromosome. The immunological evaluation revealed increased IgM serum levels and a low proliferative response to mitogens, PHA and CD3 cross-linking (CD3 XL). After 12 years of age only a mild dysmetria persisted, while the proliferative response to mitogens became normal by 9 years of age.

13q deletion syndrome is caused by the absence of a portion of the long arm of chromosome 13. This syndrome is a rare condition characterized by a wide range of clinical findings. Phenotype varies with the location and size of the deletion. We report a female dizygotic twin with a proximal deletion of 13q and failure to thrive, hypotonia, and multiple anomalies included pytosis and total ophthalmology at right side, strabismus at left, bilateral iris heterochromia and telecantus. She had a broad nasal bridge with flat philtrum, micrognathia and antevert ear lobes. Her umbilicus had vanished. Her left coxa was dislocated and left toes were overlapped. She was also found to have hypertriglyceridemia, hypercholesterolemia, and hypothyroidism. Chromosome analysis showed a proximal deletion of chromosome 13 [karyotype 46,XX,del(13) (q14.2q31.3)] which was confirmed by high-resolution microarray based comparative genomic hybridization. The described patient is unique among similar rare cases with different deletion breakpoints. It is the first case of 13q14.2q31.3 deletion where the breakpoints are clearly defined, indicating the importance of detailed clinical description and high-resolution genomic analysis for characterization of rare genetic syndromes.

Objective To present array comparative genomic hybridization (aCGH) characterization of partial monosomy 13q (13q21.32→qter) and partial trisomy 8p (8p12→pter) presenting with anencephaly and increased nuchal translucency (NT). Case Report A 34-year-old primigravid woman was referred to the hospital at 12 weeks of gestation for termination of the pregnancy because of major structural abnormalities of the fetus. Prenatal ultrasound revealed a malformed fetus with anencephaly and an increased NT thickness of 5 mm at 12 weeks of gestation. Cytogenetic analysis of the fetus revealed a derivative chromosome 13. The mother was subsequently found to carry a balanced reciprocal translocation between 8p12 and 13q21. Bacterial artificial chromosome-based aCGH using fetal DNA demonstrated partial trisomy 8p and partial monosomy 13q [arr cgh 8p23.3p12 (RP11-1150M5→RP11-1145H12)×3, 13q21.32q34 (RP11-326B4→RP11-450H16)×1]. Oligonucleotide-based aCGH showed a 36.7-Mb duplication of distal 8p and a 48.4-Mb deletion of distal 13q. The fetal karyotype was 46,XY,der(13) t(8;13)(p12;q21.32)mat. The maternal karyotype was 46,XX,t(8;13)(p12;q21.32). Conclusion The 13q deletion syndrome can be associated with neural tube defects and increased NT in the first trimester. Prenatal sonographic detection of neural tube defects should alert chromosomal abnormalities and prompt cytogenetic investigation, which may lead to the identification of an unexpected parental translocation involving chromosomal segments associated with neural tube development.

BACKGROUND AND PURPOSE: Although pineoblastoma is the main brain abnormality associated with hereditary retinoblastoma, recent studies suggest an association with pineal cysts. This association is important because some pineoblastomas mimic pineal cysts. If there is a relationship, then radiologists should be aware of it because diagnostic confusion is possible. Mental retardation and congenital brain anomalies are also reported in patients with retinoblastoma, mostly in combination with 13q deletion syndrome. In this retrospective study, the presence of brain abnormalities on MR images in a large group of consecutive patients with retinoblastoma is evaluated. MATERIALS AND METHODS: Brain MR images of 168 patients with retinoblastoma from 1989 to 2009 were evaluated by 2 radiologists for tumors, structural anomalies, myelinization, and coincidental findings. Clinical records were reviewed for laterality, heredity, and the presence of the 13q deletion syndrome. RESULTS: The hereditary group (patients with bilateral and unilateral proved RB1-germline mutation) included 90 (54%) of 168 patients. Seven patients had 13q deletion syndrome. Normal findings on brain MR images were seen in 150 (89%) patients. Five pineoblastomas were detected, all in patients with hereditary retinoblastoma (5.5% in the hereditary subgroup). Nine pineal cysts were detected (2.2% in the hereditary subgroup). Corpus callosum agenesis was found in 1 patient and a Dandy-Walker variant in 1 patient, both in combination with 13q deletion syndrome. CONCLUSIONS: Pineoblastoma is associated with hereditary retinoblastoma, and structural brain abnormalities are restricted to patients with the 13q deletion syndrome. The incidence of pineal cysts in patients with retinoblastomas is similar to that in healthy children and is not associated with hereditary retinoblastoma.

Waardenburg-Shah syndrome (Waardenburg syndrome type IV-WS4) is an auditory-pigmentary disorder that combines clinical features of pigmentary abnormalities of the skin, hair and irides, sensorineural hearing loss, and Hirschsprung disease (HSCR). Mutations in the endothelin-B receptor (EDNRB) gene on 13q22 have been found to cause this syndrome. Mutations in both alleles cause the full phenotype, while heterozygous mutations cause isolated HSCR or HSCR with minor pigmentary anomalies and/or sensorineural deafness. We investigated the status of the EDNRB gene, by FISH analysis, in three patients with de novo proximal 13q deletions detected at cytogenetic analysis and examined the clinical variability of WS4 among these patients. Chromosome 13q was screened with locus specific FISH probes and breakpoints were determined at 13q22.1q31.3 in Patients I and 3, and at 13q21.1q31.3 in Patient 2. An EDNRB specific FISH probe was deleted in all three patients. All patients had common facial features seen in proximal 13q deletion syndrome and mild mental retardation. However, findings related to WS4 were variable; Patient 1 had hypopigmentation of the irides and HSCR, Patient 2 had prominent bicolored irides and mild bilateral hearing loss, and Patient 3 had only mild unilateral hearing loss. These data contribute new insights into the pathogenesis of WS4. (C) 2009 Wiley-Liss, Inc. (Less)

The phenotypic description of deletion 13q syndrome is dependent on the location and size of the deleted segment. At present, the syndrome is divided into 3 groups based on the deletion's location relative to chromosomal band 13q32. Groups 1 (proximal to q32) and 2 (including q32) have shown distinctive phenotypes including mental retardation and growth deficiency, whereas group 3 (q33-34 deletion) is defined by the presence of mental retardation but usually the absence of major malformations. The authors report an 8-year-old Hispanic female with dysmorphic facial features, microcephaly, moderate to severe mental retardation, and uncontrolled epilepsy associated with a terminal 13q33.3 deletion. These features expand the characterization of the phenotype associated with group 3 of the 13q deletion syndrome to include major clinical manifestations. This case report will contribute to more accurate genetic counseling as well as may help identify more individuals with this syndrome.

Partial deletions on the long arm of chromosome 13 lead to a number of different phenotypes depending on the size and position of the deleted region. The present study investigated 2 patients with 13q terminal (13qter) deletion syndrome, which manifested as anal atresia with rectoperineal fistula, complex type congenital heart disease, esophageal hiatus hernia with gastroesophageal reflux, facial anomalies and developmental and mental retardation. Array comparative genomic hybridization identified 2 regions of deletion on chromosome 13q31‑qter; 20.38 Mb in 13q31.3‑qter and 12.99 Mb in 13q33.1‑qter in patients 1 and 2, respectively. Comparisons between the results observed in the present study and those obtained from patients in previous studies indicate that the gene encoding ephrin B2 (EFNB2) located in the 13q33.3‑q34 region, and the gene coding for endothelin receptor type B, in the 13q22.1‑31.3 region, may be suitable candidate genes for the observed urogenital/anorectal anomalies. In addition, the microRNA‑17‑92a‑1 cluster host gene and the glypican 6 gene in the 13q31.3 region, as well as EFNB2 and the collagen type IV a1 chain (COL4A1) and COL4A2 genes in the 13q33.1‑q34 region may together contribute to cardiovascular disease development. It is therefore possible that these genes may be involved in the pathogenesis of complex type congenital heart disease in patients with 13q deletion syndrome.

We describe a boy with moderate intellectual disability associated with distinctive hand malformations (hypoplastic and angel-shaped middle phalanges) and partial growth hormone (GH) deficiency associated with mosaic deletion of 13q31.1-13q32.3. The deleted segment was mapped to a 20-Mb region bounded by BACs RP11-1143C2 and RP11-139C1, narrowing the previously described locus for hand malformations at this region and suggesting that a locus for GH deficiency is also present at this location. The deleted segment contains at least three candidate genes, glypican-5, FARP1 and SOX21, that may be contributing to the phenotype in this boy. In a significant proportion (approximately 50%) of cells, the deleted region is present as a supernumerary ring chromosome stabilized by the formation of a neocentromere at 13q31-q32, within a region with a known propensity for neocentromere formation. The ring chromosome appears to be prone to low-level misdivision and loss in vitro which, in vivo, must be countered by selection for the balanced karyotype because the level of mosaicism has remained stable over 13 years.

We present a case of a child with del(13) (q31.1qter), VACTERL association, and penoscrotal transposition. Deletion of the distal long arm of chromosome 13 is associated with variable phenotypes. These phenotypes are divided into three clusters; each cluster represents a specific deleted segment of 13q. Individuals with deletions of a critical region at 13q32 have multiple congenital malformations that include components of the VACTERL association. Our patient had all six manifestations of VACTERL association. In addition, he had complete penoscrotal transposition, a unique malformation reported rarely in VACTERL association and only twice previously in deletion of distal 13q. We reviewed all reported cases of distal 13q deletions to date. Of these 137 patients, 15 could be classified into the VACTERL association. Ours was the only patient with distal 13q deletion and all VACTERL association features and also the only one with tracheoesophageal fistula. Neither holoprosencephaly nor the other central nervous system malformations that have been seen in individuals with distal 13q deletions were apparent in him. The patient presented here appears to be unique among individuals with distal 13q deletion. His cluster of malformations strengthens the argument that distal 13q deletion is a cause for VACTERL association, and that this causal relationship implies a syndromic form of VACTERL. In addition, this case and those ascertained from the literature suggest that penoscrotal transposition should be considered part of both the distal 13q-deletion syndrome and some forms of VACTERL association.

Neural tube defects (NTD) are common findings in the 13q deletion syndrome, but the relationship between the 13q- syndrome and NTDs is poorly understood. We present a child with a 13q deletion and lumbosacral myelomeningocele. This was a boy with microcephaly, telecanthus, minor facial anomalies, and ambiguous genitalia. Cytogenetic and fluorescence in situ hybridization analysis showed a de novo 46,XY,del(13)(q33.2qter) with no visible translocation. By using microsatellite markers, the deletion breakpoint was mapped to a 350-kb region between D13S274 and D13S1311 and was paternal in origin. An analysis of 13q deletions with NTDs, including the present case, suggests that a deletion in 13q33-34 is sufficient to cause an NTD. The deletions associated with NTDs are distal to and nonoverlapping with the previously defined critical region in 13q32 for the major malformation syndrome [Brown et al., 1999: Am J Hum Genet 57: 859–866]. Our analysis also suggests that one or more genes in 13q33-34 produces NTDs by haploinsufficiency. Am. J. Med. Genet. 91:227–230, 2000. © 2000 Wiley-Liss, Inc.

We report a boy with constitutional deletion 13q chromosome associated with dysmorphic features and bilateral retinoblastoma. The patient developed secondary Burkitt lymphoma 5 years after the diagnosis of retinoblastoma at the age of 8 months. He has completed treatment for both malignancies. At present, he is 7 years old and still in remission.

Purpose The advent of cochlear implantation has been followed by an explosion in surgical and technological advances with subsequent alterations in the treatment of sensorineural hearing loss management. Many individuals with rare genetic abnormalities who once may have not been considered candidates for cochlear implantation are now benefiting from cochlear implantation. One of these unusual syndromes is the 13q deletion syndrome. The clinical features of 13q deletion syndrome, a rare chromosomal abnormality, were originally described in the early 1960s, though the literature currently lacks defined phenotypic abnormalities. Patients with 13q deletion syndrome present with varying degrees of cognitive and growth delay, craniofacial dysmorphisms, and congenital malformations. The etiology of the sensorineural hearing loss has not been elucidated, and genes associated with other syndromes which include sensorineural hearing loss have been proposed as the causative agents. We describe the unique clinical and surgical considerations for 13q deletion syndrome and review the considerations when deliberating on cochlear implantation in syndromic hearing loss. Materials and Methods Case report. Results Successful cochlear implantation in a patient with 13q deletion syndrome. Conclusion Many patients with 13q deletion syndrome suffer from sensorineural hearing loss, and when appropriately selected may likely benefit from cochlear implantation. Many other syndromic patients following careful selection may also benefit from cochlear implantation and should not be excluded from consideration until appropriately evaluated.

BACKGROUND Retinoblastoma is the most common primary intraocular malignancy of childhood, arising from retinal progenitor cells. The most common presenting feature is leucocoria, followed by strabismus, defective vision, and rarely nystagmus. The unusual associations reported with retinoblastoma are well-differentiated liposarcoma and lipomatous tissues, chromosome breakage syndromes, and the myriad findings of rare 13q deletion syndrome. METHOD Case report. RESULTS An 8-year-old boy presented with features of retinoblastoma, having leucocoria in the left eye and an unusual association of postaxial polydactyly in the left hand. CONCLUSIONS Postaxial polydactyly should be considered as an association of retinoblastoma.

Children with constitutional deletion of the long arm of chromosome 13 are at risk for retinoblastoma (RB) due to loss of the RB tumor suppressor gene. The prognosis is poor since the tumors are often bilateral, aggressive, and recurrent and the patients often harbor other congenital abnormalities. One further complication is that of therapy-related malignancies later in life. We report a case of allogeneic stem cell transplantation for therapy-related acute myeloid leukemia in an 8-year-old girl after multimodality treatment for refractory bilateral relapsing RB, with excellent outcome in both the ophthalmic and marrow disease.

A 10-month-old boy, known to have the 13q deletion syndrome, presented with leukocoria in a microphthalmic right eye. He was found to have bilateral retinoblastoma requiring enucleation of the right eye and laser, cryotherapy and external beam radiation to the left eye. This case demonstrates that retinoblastoma may be present in a microphthalmic eye and that more than one imaging modality should be used in the evaluation of suspected retinoblastoma, as calcification may be absent on the computed tomography scan but present on B-mode ultrasound. Children with a known 13q deletion require immediate and serial ophthalmological examinations.

13q deletion syndrome is a rare genetic disorder, especially for group 3 deletion (13q33-q34 deletion). Previously we described a patient with congenital heart defect and mental retardation and proposed that a distal 6Mb region might contain the causative gene of congenital heart defect. Here we present a new patient with congenital heart defects (CHD), hand and foot anomalies and mild mental retardation. We identified a 1.1Mb deletion at chromosome 13q34 with high resolution SNP-array BeadChips (HumanOmni1-Quad, Illumina, USA). This chromosome region contains ten annotated genes, including GRK1, TFDP1, RASA3 and GAS6. To our knowledge, this represents the smallest 13q34 deletion identified to date. Our study provides additional support that distal 13q34 deletion region might contain key gene(s) responsible for cardiac development.

PURPOSE To report the case of identical dichorionic diamniotic female twins with unilateral retinoblastoma in 13q deletion syndrome. METHODS Clinical and ophthalmoscopic evaluation, combination of multiple ligation-dependent probe amplification, array-comparative genomic hybridization analyses, and magnetic resonance imaging were performed. RESULTS Peculiar facial features, marked hypotonia, gastroesophageal reflux, interatrial septal defect with left to right shunt and light dilatation of right chambers, 5th finger hypoplasia, 3rd-5th toes clinodactyly, 2nd toe overlapped to 3rd toe, and cutis marmorata were found. Ophthalmoscopic evaluation revealed unilateral retinoblastoma in both girls. Magnetic resonance imaging detected corpus callosum hypoplasia in both twins. A 34.4-Mb deletion involving bands 13q13.2-q21.33 and including the RB1 gene was identified in both twins. The deletion was not present in the DNA of their parents and older brother. CONCLUSIONS Dysmorphic features in children must be always suspicious of 13q deletion syndrome and a short ophthalmoscopic follow-up is necessary to detect the presence of a retinoblastoma.

13q deletion syndrome is a rare genetic disorder caused by deletions of the long arm of chromosome 13. Patients with 13q deletion display a variety of phenotypic features. We describe a one-year-old female patient with congenital heart defects (CHD), facial anomalies, development and mental retardation. We identified a 12.75Mb deletion in chromosome region 13q33.1-34 with high resolution SNP Array (Human660W-Quad, Illumina, USA). This chromosome region contains about 55 genes, including EFNB2, ERCC5, VGCNL1, F7, and F10. Comparing our findings with previously reported 13q deletion patients with congenital heart defects, we propose that the 13q33.1-34 deletion region might contain key gene(s) associated with cardiac development. Our study also identified a subclinical deficiency of Factors VII and X in our patient with Group 3 of 13q deletion syndrome.

We report on 14 patients with partial deletions of chromosome 13q. These patients exhibit a wide spectrum of phenotypes. Deletions limited to proximal bands q13-q31 are associated with growth retardation but not with major malformations. We review the literature since 1975 and summarize 13q deletion cases which have a phenotype involving one or more major malformations and mental retardation. Analysis of the breakpoints of these cases, as well as those reported by us, supports the hypothesis that only deletions involving at least part of band q32 are associated with major malformations and digital abnormalities. Patients with more distal deletions have severe mental retardation but do not have major malformations or growth retardation. A group of patients in whom the breakpoint is stated to be within q32 has had an intermediate phenotype. This suggests that it may be possible to define subregions within q32 whose deletion is associated with particular developmental defects.

Purpose We report two (twin A and twin B) cases of unilateral retinoblastoma in identical female twins with 13q deletion syndrome. Family history for retinoblastoma was negative. Karyotypic analyses (peripheral lymphocytes) of the brother and their parents showed no abnormalities. Methods Twin A has demonstrated unilateral, multifocal retinoblastoma (left eye), diagnosed at the age of 5 months, which was recalcitrant to systemic chemoreduction, than treated with intraarterial chemotherapy. Twin B has demonstrated unilateral unifocal retinoblastoma (right eye) at 9 months of age, successfully treated with brachytherapy. Both had prominent eyebrows, broad nasal bridge, large, prominent, low – set ears, bulbous tipped nose, large mouth, and thin upper lip. MRI revealed ventricles dilatation associated with corpus callosum agenesis. DNA analysis was performed with polymorphic microsatellite markers to confirm monozygosity. Single-stranded conformation polymorphism and Southern blot analysis of the retinoblastoma gene were performed. Results Molecular genetic analyses confirmed monozygosity. Conclusion We describe two cases of 13q deletion syndrome in bicorial identical twins.

International audience; 13q deletion is characterized by a wide phenotypic spectrum resulting from a partial deletion of the long arm of chromosome 13. The main clinical features are mental retardation, growth retardation, craniofacial dysmorphy and various congenital defects. Only one recent Italian study was aimed at determining genotype-phenotype correlations among 13q deletions from a group of mainly live born children, using array-CGH and FISH. In order to improve the molecular characterization of 13q monosomy, 12 new patients (9 foetuses and 3 children) were collected based on a cohort of holoprosencephaly (HPE) linked to ZIC2 gene deletion and/or patients with 13q deletion diagnosed by standard karyotype. First, quantitative gene screening using MLPA (Multiplex Ligation dependent Probe Amplification) was performed to look for ZIC2 gene deletion and then, CGH array analysis was carried out using the Agilent Human Genome CGH microarray 4x44K (Agilent Technologies, Santa Clara, USA). All the foetuses had severe cerebral midline malformations associated with a deletion including the ZIC2 gene. We report one patient with Steinfeld phenotype linked to this chromosomal anomaly, and suggest that some of the associations between cerebral midline malformation and limb defects might be related to 13q deletion. Further candidate genes are suspected to explain the malformations associated with cerebral anomalies in the hypothesis of a contiguous gene syndrome: SPRY2 in 13q31.1 is implicated in lens cell proliferation and differentiation for congenital cataract; GPC5 in 13q32 is mainly expressed in the mesenchyme of the developing limb bud for upper limb anomalies.