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Karyotypic analysis showing ring chromosome 17. (a) G-banded karyotype showing ring chromosome 17 (arrowed). (b) Fuorescence in situ hybridisation with probes from 17q21 (RARA) and 17p13.3 (Oncor D17s379, Miller Dieker region) showed that both probes are present on ring chromosome. This confirms that there is loss of little chromosome material from the P arm of chromosome 17. (c) Ideogram of the ring 17 chromosome.
Source publication
Eye is the official journal of the Royal College of Ophthalmologists. It aims to provide the practising ophthalmologist with information on the latest clinical and laboratory-based research.
Contexts in source publication
Context 1
... chromosome 17 was first described in 1970. There have been 4 previous reports of flecked retina associated with ring chromosome. We report another case of ring chromosome 17 with flecked retina. We present a 25-year-old boy, who presented 23 years ago with myoclonic seizure, learning disability, and developmental delay. There were no signs of dysmorphism or any skin lesions. CT scan of the head showed no definite abnormalities. No family history of seizures or visual problems were reported. Ocular examination at the age of 16 years revealed VA of 6/6 in both eyes. Low-frequency jerk nystagmus was apparent on dextroversion. Fundoscopy revealed well- defined white foveal flecks at the level of retinal pigment epithelium in both eyes (Figure 1). Karyotype analysis (Figure 2) showed 46 XY, r(17)(p13.3q25) with no obvious loss of genetic material. Fluorescence in situ hybridisation studies (Figure 2) using the Oncor D17s379 probe from the Miller–Dieker chromosome region on 17p13.3, revealed no deletion. Probes within 300 kb of each telomere showed signals on normal chromosome 17 only, suggesting that at least 300 kb of material has been lost from each ...
Context 2
... chromosome 17 was first described in 1970. There have been 4 previous reports of flecked retina associated with ring chromosome. We report another case of ring chromosome 17 with flecked retina. We present a 25-year-old boy, who presented 23 years ago with myoclonic seizure, learning disability, and developmental delay. There were no signs of dysmorphism or any skin lesions. CT scan of the head showed no definite abnormalities. No family history of seizures or visual problems were reported. Ocular examination at the age of 16 years revealed VA of 6/6 in both eyes. Low-frequency jerk nystagmus was apparent on dextroversion. Fundoscopy revealed well- defined white foveal flecks at the level of retinal pigment epithelium in both eyes (Figure 1). Karyotype analysis (Figure 2) showed 46 XY, r(17)(p13.3q25) with no obvious loss of genetic material. Fluorescence in situ hybridisation studies (Figure 2) using the Oncor D17s379 probe from the Miller–Dieker chromosome region on 17p13.3, revealed no deletion. Probes within 300 kb of each telomere showed signals on normal chromosome 17 only, suggesting that at least 300 kb of material has been lost from each ...
Citations
... Only 12 cases of ring chromosome 17 without involvement of MDCR have been described [Qazi et al., 1979;Gass and Taney, 1994;Endo et al., 1999;Shashi et al., 2003;Ricard-Mousnier et al., 2007;Kumari et al., 2009;Surace et al., 2009;de Palma et al., 2015]. Epilepsy has been described in detail in only 2 such cases, with focal seizures from sleep and prolonged nonconvulsive status epilepticus in wakefulness [Ricard-Mousnier et al., 2007;de Palma et al., 2015]. ...
... Ring chromosome 17 without MDCR involvement is rare [Qazi et al., 1979;Chudley et al., 1982;Charles et al., 1991;Gass and Taney, 1994;Endo et al., 1999;Shashi et al., 2003;Ricard-Mousnier et al., 2007;Kumari et al., 2009;Surace et al., 2009;de Palma et al., 2015]. Epilepsy, although reported in all cases, is well described in only 2 patients, both presenting with nocturnal focal seizures and prolonged diurnal nonconvulsive status epilepticus [Ricard-Mousnier et al., 2007;de Palma et al., 2015]. ...
... Only 12 cases of ring chromosome 17 without involvement of MDCR have been described [Qazi et al., 1979;Gass and Taney, 1994;Endo et al., 1999;Shashi et al., 2003;Ricard-Mousnier et al., 2007;Kumari et al., 2009;Surace et al., 2009;de Palma et al., 2015]. Epilepsy has been described in detail in only 2 such cases, with focal seizures from sleep and prolonged nonconvulsive status epilepticus in wakefulness [Ricard-Mousnier et al., 2007;de Palma et al., 2015]. ...
... Ring chromosome 17 without MDCR involvement is rare [Qazi et al., 1979;Chudley et al., 1982;Charles et al., 1991;Gass and Taney, 1994;Endo et al., 1999;Shashi et al., 2003;Ricard-Mousnier et al., 2007;Kumari et al., 2009;Surace et al., 2009;de Palma et al., 2015]. Epilepsy, although reported in all cases, is well described in only 2 patients, both presenting with nocturnal focal seizures and prolonged diurnal nonconvulsive status epilepticus [Ricard-Mousnier et al., 2007;de Palma et al., 2015]. ...
Chromosomal abnormalities are often identified in people with neurodevelopmental disorders including intellectual disability, autism, and epilepsy. Ring chromosomes, which usually involve gene copy number loss, are formed by fusion of subtelomeric or telomeric chromosomal regions. Some ring chromosomes, including ring 14, 17, and 20, are strongly associated with seizure disorders. We report an individual with a ring chromosome 17, r(17)(p13.3q25.3), with a terminal 17q25.3 deletion and no short arm copy number loss, and with a phenotype characterized by intellectual disability and drug-resistant epilepsy, including a propensity for nonconvulsive status epilepticus.
... Five cases of ring chromosome 17 have been reported with ocular involvement, all with features of short stature, mental retardation, epilepsy and café au lait spot in addition to a flecked retina appearance (Charles et al., 1991;Gass and Taney, 1994;Kumari et al., 2009;Ono et al., 1974;Shashi et al., 2003). Despite these retinal changes, no visual loss has been recorded in any of the cases (all under 34 years old). ...
Drusen are discussed frequently in the context of their association with age-related macular degeneration (AMD). Some types may, however, be regarded as a normal consequence of ageing; others may be observed in young age groups. They also occur in a number of inherited disorders and some systemic conditions. Whilst drusen are classically located external (sclerad) to the retinal pigment epithelium, accumulations of material internal (vitread to) this layer can display a drusen-like appearance, having been variously termed pseudodrusen or subretinal drusenoid deposits. This review first briefly presents an overview of drusen biogenesis and subclinical deposit. The (frequently overlapping) subtypes of clinically detectable deposit, seen usually in the context of ageing or AMD, are then described in more detail, together with appearance on imaging modalities: these include hard and soft drusen, cuticular drusen, reticular pseudodrusen and “ghost drusen”. Eye disorders other than AMD which may exhibit drusen or drusen-like features are subsequently discussed: these include monogenic conditions as well as conditions with undefined inheritance, the latter including some types of early onset drusen such as large colloid drusen. A number of systemic conditions in which drusen-like deposits may be seen are also considered. Throughout this review, high resolution images are presented for most of the conditions discussed, particularly the rarer ones, providing a useful reference library for images of the range of conditions associated with drusen-like appearances. In the final section, some common themes are highlighted, as well as a brief discussion of some future avenues for research.
... The present patient exhibited a chromosomal abnormality which has not previously reported in connection to CNL. At present, R banding and conventional karyotyping analysis have identified numerous cases of numerical and structural abnormalities of chromosome 17, including chromosome 17 polysomy in metastatic breast cancer (18), isochromosome 17q in acute promyeloblastic leukemia (19), ring 17 chromosome in flecked retina (20), prenatal diagnosis of trisomy 17 mosaicism (21) and monosomy 17 in CML (18). Consequently, chromosome 17 is notable among the human chromosomes in a number of respects. ...
Chronic neutrophilic leukemia (CNL) is an infrequently encountered myeloproliferative disorder characterized by sustained neutrophilic leukocytosis, hepatosplenomegaly and the absence of the Philadelphia chromosome. This study presents a 60-year-old male patient with a diagnosis corresponding to the WHO classification criteria for CNL who was treated at the First Affiliated Hospital of Harbin Medical University (Harbin, China). Chromosome analysis of the patient’s bone marrow cells showed 44, XY, -17, -17 in all 20 metaphase spreads. Homoharringtonine was used to control the patient’s high white cell count for a short time, although after two weeks, the patient complained of left upper quadrant discomfort and his blood count showed a white blood cell count of 40.8×109/l. However, the patient continued to undergo maintenance therapy and was discharged in good clinical condition with hydroxyurea treatment for 31 months. Usually, patients with CNL have normal karyotypes and no specific cytogenetic abnormalities have been identified. To the best of the authors’ knowledge, this is the first case in the literature of a patient exhibiting the deletion of chromosome 17 with CNL. We concluded that deleted of tumor suppressor genes located on 17p13.1, such as p53, may be associated with the development of CNL. Patients with CNL have a poor prognosis, although the present patient has exhibited a prolonged stable phase with oral chemotherapy drug treatment.
Ring chromosome 17 (RC17) that replaces a normal chromosome 17 homologue is extremely rare, and only about 20 RC17 cases were reported in literature. RC17 is usually associated with deletion of the terminal regions of chromosome 17. When the deletion included the PAFAH1B1 gene at 17p13.3, the carriers showed phenotypes resembling Miller–Dieker lissencephaly syndrome (MDLS), with lissencephaly, intellectual disability, seizures, and severe postnatal growth deficiency. If PAFAH1B1 was not deleted, the individuals with RC17 may show clinical features, including growth failure, mild intellectual disability, seizures, flecked retina, and café au lait spots. These features were even milder in RC17 cases with the presence of normal cells. Some RC17 cases were mosaic for RC17 and monosomy 17. Loss of a copy of tumor suppressor genes on chromosome 17, such as TP53, NF1, and BRCA1, potentially increased the risk of cancer. Since each RC17 can be unique for its ring structure, type and level of mosaicism, and genomic content, detailed cytogenomic characterization and comprehensive clinical evaluation are essential for accurate diagnostic interpretation, genetic counseling, and clinical management for patients of RC17.
