Intractable epilepsy, growth failure, hypothyroidism, and cataract: rare clinical manifestations in a patient with ring chromosome 20 syndrome

@#Ring chromosome 20 [r(20)] syndrome is typically characterized by intractable epilepsy, variable degrees of behavior problems and cognitive deficits, and an absence of or minimal dysmorphic features. Here we report a case diagnosed with r(20) syndrome exhibiting rare clinical manifestations of intractable epilepsy, growth failure, hypothyroidism, and cataract. This 17-year-old female patient who showed growth failure and no dysmorphic features had the first seizure at the age of 8 years. The seizure pattern was described as periods of non-convulsive status epilepticus with prolonged confusional state, motionless stare, mutism, and subtle motor seizures, lasting for minutes to hours. The interictal EEG showed bilateral synchronous, rhythmic high voltage delta waves intermixed with occasional spikes over the bilateral frontal areas. The seizures were refractory to medical treatments. Hypothyroidism and cataract were subsequently diagnosed at the age of 16 years and 17 years, respectively. Chromosome study showed a female genome with r(20) mosaicism. In conclusion, r(20) syndrome might cause multisystemic involvement, and therefore, comprehensive surveys of the central nervous system, ophthalmologic system, and endocrine system, among others, are crucial.

Cromosoma 13 en anillo / Ring chromosome 13

Resumen Introducción: El cromosoma 13 en anillo es una alteración citogenética infrecuente, clínicamente caracterizada por presentar retraso del crecimiento, del desarrollo psicomotor y déficit cognitivo, además de microcefalia, dismorfia facial, alteraciones genitales e hipoplasia del pulgar. Caso clínico: Paciente de 8 meses de edad evaluado por presentar talla baja, retraso del desarrollo psicomotor, microcefalia, dismorfia facial, hipospadias peneoescrotales e hipoplasia de pulgar. Se evidenció lisencefalia, hipoacusia neuroconductiva del lado derecho y comunicación interauricular tipo ostium secundum pequeña. El estudio citogenético del paciente mostró 46, XY, r (13) en 30 células analizadas. Conclusiones: Se resaltan los hallazgos clínicos que pueden orientar el diagnóstico de esta alteración cromosómica estructural infrecuente, destacando, además, la evaluación médica interdisciplinaria requerida y el adecuado asesoramiento genético familiar.

Abstract Background: Ring chromosome 13 is an infrequent cytogenetic disorder clinically characterized by growth and psychomotor development retardation, cognitive deficit, microcephaly, facial dysmorphism, genital alterations and thumb hypoplasia. Case report: A 8-month-old patient was evaluated for presenting short stature, psychomotor development delay, microcephaly, facial dysmorphism, penoscrotal hypospadias and thumb hypoplasia. Lissencephaly, neuroconductive hearing loss on the right side and small ostium secundum interatrial communication were evident. The cytogenetic study of the patient showed 46, XY, r (13) in 30 cells analyzed. Conclusions: Clinical findings that can guide the diagnosis of this infrequent structural chromosomal alteration are highlighted, as well as the interdisciplinary medical evaluation required and adequate family genetic counseling.

Analysis of clinical and electroencephalogram characteristics of ring chromosome 14 syndrome / 中华实用儿科临床杂志

Objective To investigate the clinical and electroencephalogram (EEG) characteristics and treatment of ring chromosome 14 syndrome,and to improve its early recognition and accurate diagnosis.Methods The clinical and EEG characteristics of 4 patients with ring chromosome 14 syndrome confirmed by genetic diagnosis were analyzed in the neurology outpatient department and ward of pediatrics in Peking University First Hospital from August 2012 to August 2018.The treatment and prognosis of the 4 patients were followed up.Results Of the 4 patients,there were 2 males and 2 females.All the patients had developmental delay,abnormal facial features such as wide eye spacing,low nasal bridge and microcephaly.Seizures occurred in all the patients with varying onset ages from 8 months to 1 year.Seizure types included focal seizure,tonic seizure and generalized tonic-clonic seizure.EEG monitoring ages varied from 9 months to 4 years and 4 months.The characteristic EEG pattern manifested as slow activity of background,unilateral or bilateral anterior,posterior or diffuse slow activity,with or without interposed multifocal epileptiform discharges.Cranial magnetic resonance imaging (MRI) showed non-specific abnormality in 1 patient and normal in 3 patients.The ages at the last follow-up ranged from 1 year and 8 months to 7 years and 1 month with intervals from 9 months to 6 years and 5 months.Valproic acid combined with other antiepileptic drugs was used to treat seizures.Seizure reduction instead of control was observed in all the 4 cases.At the last follow-up,the development of movement and language were all delayed in the 4 patients.One case could walk independently,three could walk unsteadily alone;two could speak 2-3 simple words,one could call only " baba,mama",and one had no language development.Conclusions The ring chromosome 14 syndrome is a rare disease caused by chromosome abnormality.Its main clinical manifestations included facial abnormalities,microcephaly,epilepsy,developmental delay especially for language and cognitive disability.The types of seizures included both focal and generalized.EEG showed non-specific features with slow background activity,with the migratory slow waves mixing multi-focal discharges as the main common pattern.The epilepsy of this disease was often drug resistant.Valproic acid combined with other antiepileptic drugs could reduce seizures.Seizures without control could further affect development outcome.

Analysis of clinical and electroencephalogram characteristics of ring chromosome 14 syndrome / 中华实用儿科临床杂志

Objective@#To investigate the clinical and electroencephalogram (EEG) characteristics and treatment of ring chromosome 14 syndrome, and to improve its early recognition and accurate diagnosis.@*Methods@#The cli-nical and EEG characteristics of 4 patients with ring chromosome 14 syndrome confirmed by genetic diagnosis were analyzed in the neurology outpatient department and ward of pediatrics in Peking University First Hospital from August 2012 to August 2018.The treatment and prognosis of the 4 patients were followed up.@*Results@#Of the 4 patients, there were 2 males and 2 females.All the patients had developmental delay, abnormal facial features such as wide eye spacing, low nasal bridge and microcephaly.Seizures occurred in all the patients with varying onset ages from 8 months to 1 year.Seizure types included focal seizure, tonic seizure and generalized tonic-clonic seizure.EEG monitoring ages varied from 9 months to 4 years and 4 months.The characteristic EEG pattern manifested as slow activity of background, unilateral or bilateral anterior, posterior or diffuse slow activity, with or without interposed multifocal epileptiform discharges.Cranial magnetic resonance imaging (MRI) showed non-specific abnormality in 1 patient and normal in 3 patients.The ages at the last follow-up ranged from 1 year and 8 months to 7 years and 1 month with intervals from 9 months to 6 years and 5 months.Valproic acid combined with other antiepileptic drugs was used to treat seizures.Seizure reduction instead of control was observed in all the 4 cases.At the last follow-up, the development of movement and language were all delayed in the 4 patients.One case could walk independently, three could walk unsteadily alone; two could speak 2-3 simple words, one could call only " baba, mama" , and one had no language development.@*Conclusions@#The ring chromosome 14 syndrome is a rare disease caused by chromosome abnormality.Its main clinical manifestations included facial abnormalities, microcephaly, epilepsy, developmental delay especially for language and cognitive disability.The types of seizures included both focal and generalized.EEG showed non-specific features with slow background activity, with the migratory slow waves mixing multi-focal discharges as the main common pattern.The epilepsy of this disease was often drug resistant.Valproic acid combined with other antiepileptic drugs could reduce seizures.Seizures without control could further affect development outcome.

Molecular cytogenetic diagnosis of a case with ring chromosome 18 syndrome / 中华医学遗传学杂志

Objective@#To explore the genetic basis for a child with developmental delay and congenital syndactyly.@*Methods@#G-banding chromosomal karyotyping and chromosomal microarray analysis (CMA) were performed on peripheral blood sample from the child.@*Results@#The child was ascertained as 46, XY, r(18)[52]/45, XY, ? 18[3]. A 18q21.32-q23 deletion was identified by CMA with a size of 19.85 Mb, which has encompassed 99 genes including CTDP1, TXNL4A, TSHZ1, PIGN, RTTN, TNFRSF11A, KDSR and CYB5A.@*Conclusion@#Clinical phenotype of the patient with ring chromosome 18 is associated with the size of the euchromatin loss and involved genes. As a useful complement to conventional karyotyping, CMA has provided an powerful tool for delineating complex chromosomal aberrations.

Síndrome del anillo del cromosoma 18: reporte de un caso y revisión de la literatura / Chromosome 18 ring syndrome: case report and review of the literature

El Síndrome del Anillo del Cromosoma 18 (18 [(r)18]) es un trastorno cromosómico que se incluye dentro de las anomalías estructurales desequilibradas donde dicho cromosoma se encuentra en forma de anillo el cual resulta de la pérdida simultánea de ambos segmentos terminales de los brazos corto y largo con la subsecuente fusión de sus extremos, constituyendo una estructura circular que microscópicamente se asemeja a un anillo, de allí su nomenclatura r (del inglés ring, que significa anillo). Tiene una incidencia de 1/40.000 nacidos vivos y hasta la fecha se han reportado aproximadamente entre 80 a 100 casos a nivel mundial sin embargo sólo existen alrededor de nueve reportes de r(18) en mosaico, aislado o asociado con otras alteraciones cromosómicas. A continuación, se presenta el caso de una paciente pediátrica con Síndrome del Anillo del cromosoma 18 estudiado y diagnosticado en la Unidad de Genética Médica de la Universidad Centroccidental Lisandro Alvarado en Barquisimeto, Venezuela, con la correspondiente revisión de la literatura relacionada con este síndrome(AU)

Chromosome 18 Ring Syndrome (18 [(r) 18]) is a chromosomal disorder that is included among the unbalanced structural anomalies in which chromosome 18 has a ring form which results from the simultaneous loss of both terminal segments of the short and long arms with the subsequent fusion of their ends forming a circular structure that microscopically resembles a ring, hence its nomenclature r (of the English ring, which means ring).18r Syndrome has an incidence of 1/40,000 live births; to date approximately 80-100 cases worldwide have been reported. There are only about nine reports of r(18) in mosaic, isolated or associated with other chromosomal alterations. We present a case of a pediatric patient with Chromosome 18 Ring Syndrome, evaluated and diagnosed in the Unidad de Genética Médica of the Universidad Centroccidental Lisandro Alvarado in Barquisimeto, Venezuela with the corresponding review of the literature(AU)

Primary Amenorrhea In Kabuki Syndrome: A Case Report

Kabuki syndrome also called as Niikawa Kuroki syndrome is a paediatric congenital disorder characterised bydistinctive facial features, skeletal anomalies, short stature, dermatoglyphic abnormalities and mentalretardation. This syndrome usually manifests with precocious puberty. We are presenting a case of Kabukisyndrome from the South-Indian population with primary amenorrhea for the first time. Further, the clinicalfeatures had considerable overlap with Turner syndrome, and chromosomal analysis revealed the presence ofring (X) chromosome with 45,X karyotype.

A patient with intractable epilepsy due to ring chromosome 20 syndrome and prenatal diagnosis for his sibling / 中华实用儿科临床杂志

Objective To investigate the clinical features,karyotype,and the prenatal diagnosis for his sibling of a Chinese patient with rare ring chromosome 20 syndrome induced intractable epilepsy.Methods The clinical data of the patient diagnosed in Peking University People's Hospital were collected.The clinical manifestations,chromosome karyotype were summarized.Results The proband,a boy,started to show intermittent tonic seizures or atypical absence seizures and psychomotor retardation from the age of 11 months.Several anti-epilepsy drugs and globulin had been tried without effect.Common karyotype analysis and epilepsy-related genes analysis revealed no abnormality.However,abnormal karyotype 46,XY,r(20)(p13q13.3) in his peripheral blood lymphocytes was found by high resolution chromosome karyotype analysis with 550 G-banding,and the diagnosis of ring chromosome 20 syndrome,type Ⅱ was confirmed.The mother of the patient underwent amniocentesis at the midterm of the second pregnancy.The cultured amniocytes karyotypes were normal.The second child(a boy) of the family was 1 year old without epilepsy and the psychomotor development was normal.Conclusions Ring chromosome 20 syndrome is a rare human chromosome abnormality.The syndrome is associated with epileptic seizures,behavior disorders and mental retardation.Since karyotype testing is not a routine investigation for the patient with epilepsy,the diagnosis of ring chromosome 20 syndrome is usually delayed or misdiagnosed.The karyotype analysis should be considered for the etiological study of the patients with intractable epilepsy with unknown origin.

Case Report of Ring Chromosome 13: 46,xx.r(13)(p13q34)/46,xx,dicr(13;13)(p13q34;p13q34).

Aims: To report a case of ring chromosome 13 in a female child. Presentation of Case: Female, Caucasian, born in Southeast of Brazil, 6 years old. Born by cesarean section, the physical examination at 6 years and 1 month old has shown: weight of 19.100 grams and 105 centimeters tall, developmental delay, bushy eyebrows, epicanthic folds and broad nasal bridge, cardiovascular and respiratory systems were normal and no abnormalities in the limbs. Chromosome analysis was performed by GTG banding of peripheral blood and the karyotype was 46,XX,r(13)(p13q34)[97]/46,XX,dic r(13;13)(p13q34;p13q34) [3]. Analysis of 100 metaphases following G-banding revealed 97% cells with a ring chromosome 13,3% with dicentric ring chromosome of two 13s. Aneuploidy was not detected. Her parents had a normal karyotype. Discussion: Some researchers relate the clinical presentation of ring chromosome 13 with the extension of the deleted chromosomal region and instability. Others suggested that phenotypes of patients can be categorized in groups, according to the breakpoint on 13q. Conclusion: The classification of cases in groups based on breakpoints and chromosomal instability is still inaccurate, with variable phenotypes. Thus, the analysis of a greater number of cases and molecular analysis are important to establish more precise correlation between genotype and phenotype.

Atypical teratoid rhabdoid brain tumor in an infant with ring chromosome 22 / 소아과

Reports of constitutional ring chromosome 22, r(22) are rare. Individuals with r(22) present similar features as those with the 22q13 deletion syndrome. The instability in the ring chromosome contributes to the development of variable phenotypes. Central nervous system (CNS) atypical teratoid rhabdoid tumors (ATRTs) are rare, highly malignant tumors, primarily occurring in young children below 3 years of age. The majority of ATRT cases display genetic alterations of SMARCB1 (INI1/hSNF5), a tumor suppressor gene located on 22q11.2. The coexistence of a CNS ATRT in a child with a r(22) is rare. We present a case of a 4-month-old boy with 46,XY,r(22)(p13q13.3), generalized hypotonia and delayed development. High-resolution microarray analysis revealed a 3.5-Mb deletion at 22q13.31q13.33. At 11 months, the patient had an ATRT (5.6 cmx5.0 cmx7.6 cm) in the cerebellar vermis, which was detected in the brain via magnetic resonance imaging.

A Case of Ring Chromosome 14 Syndrome Presenting with Intractable Epilepsy / 대한간질학회지

Ring chromosome 14 syndrome is a rare cytogenetic disorder characterized by typical facial appearance, developmental delay, and intractable epilepsy. There have been about 50 reported cases in the world and one case in Korea. Epilepsy is the most common and serious neurologic comorbidity of the syndrome and it typically begins at early ages and frequently becomes intractable. We report a girl with ring chromosome 14 syndrome who showed early onset intractable epilepsy with repetitive episodes of clustering seizures. We describe the case and the result of long term follow-up for the epilepsy. The early suspicion of the syndrome and prompt management for seizures are necessary for the favorable prognosis.

A Case of Ring Chromosome 14 Syndrome Presenting with Intractable Epilepsy

Ring chromosome 14 syndrome is a rare cytogenetic disorder characterized by typical facial appearance, developmental delay, and intractable epilepsy. There have been about 50 reported cases in the world and one case in Korea. Epilepsy is the most common and serious neurologic comorbidity of the syndrome and it typically begins at early ages and frequently becomes intractable. We report a girl with ring chromosome 14 syndrome who showed early onset intractable epilepsy with repetitive episodes of clustering seizures. We describe the case and the result of long term follow-up for the epilepsy. The early suspicion of the syndrome and prompt management for seizures are necessary for the favorable prognosis.

Phenotypic correlations in a patient with ring chromosome 22.

Ring chromosome 22, a rare cytogenetic anomaly, has been described in over 60 cases in the medical literature. The aim of this report was to present a case carrying ring chromosome 22, and her family. It is a case report of a patient presented at Medical Faculty of Çukurova University in Turkey. An 8-year-old girl with ring chromosome 22 and her family were evaluated cytogenetically and clinically. A chromosome analysis of the proband revealed a de novo 46, XX, r(22)(p11.2;q13) karyotype. Our subject demonstrated the prominent features of this syndrome including profound mental retardation, language impairment, dysmorphic features, lack of speech, hyperactivity, and behavioral disorders. There is lack of consistency between the physical abnormalities that we observed in our subject and those observed for such patients in the literature. The wide range of manifestations observed in patients with this cytogenetic alteration is probably due to size differences in the deleted region.

A Case of Mosaic Ring Chromosome 4 with Subtelomeric 4p Deletion / 대한진단검사의학회지

Ring chromosome is a structural abnormality that is thought to be the result of fusion and breakage in the short and long arms of chromosome. Wolf-Hirschhorn syndrome (WHS) is a well-known congenital anomaly in the ring chromosome 4 with a partial deletion of the distal short arm. Here we report a 10-month-old male of mosaic ring chromosome 4 with the chief complaint of severe short stature. He showed the height of -4 standard deviation, subtle hypothyroidism and mild atrial septal defect/ventricular septal defect, and also a mild language developmental delay was suspected. Brain magnetic resonance imaging showed multifocal leukomalacia. Chromosomal analysis of the peripheral blood showed the mosaic karyotype with [46,XY,r(4)(p16q35)[84]/45,XY,-4[9]/91,XXYY, dic r(4;4)(p16q35;p16q35)[5]/46,XY,dic r(4;4)(p16q35;p16q35)[2]]. FISH study showed the deletion of the 4p subtelomeric region with the intact 4q subtelomeric and WHS region. Both paternal and maternal karyotypes were normal. We compared the phenotypic variation with the previously reported cases of ring chromosome 4. The ring chromosome 4 with the subtelomeric deletion of short arm seems to be related with the phenotype of short stature.

A case of mosaic ring chromosome 13 syndrome / 소아과

The clinical features of ring chromosome 13 include mental and growth retardation, CNS anomalies, facial dysmorphism, cardiac defects, genital malformations, limb anomalies, skeletal deformities and anal malformations. Although many cases of ring chromosome 13 have been reported worldwide, only 6 cases have been reported in Korea, and the latter cases were not mosaic but pure ring chromosome 13. Here we report a case with mosaic ring chromosome 13. The baby boy was born at 37 weeks of gestation by induced vaginal delivery due to intrauterine growth restriction (IUGR). He was the second baby of a 28-year-old hepatitis B carrier mother and a 32-year-old father. There was no family history of chromosomal anomalies. The baby was a symmetric IUGR with a birth weight of 1,860 g, length of 44.8 cm, and head circumference of 29.4 cm. The physical examination revealed microcephaly, trigonocephaly, flat occiput, large ears, short neck and dysmorphic facial features, including microophthalmia, hypertelorism, antimongoloid slanting palpebral fissures, a flat nasal bridge, and micrognathia. The karyotype of this patient performed by peripheral blood lymphocytes was 46,XY,r(13)(p13q34)/45,XY,-13/46,XY,dic r(13;13)(p13q34;p13q34). The baby showed failure to thrive, hypotonia, and developmental delay. We report the first case of mosaic ring chromosome 13 in a male baby in Korea and compare this case with other Korean cases of non-mosaic ring chromosome 13.

Cytogenetic evaluation of a patient with ring chromosome 9 presenting failure to thrive and developmental delay / 소아과

We report clinical, cytogenetic, and fluorescence in situ hybridization (FISH) studies of a patient with ring chromosome 9. She presented with failure to thrive, facial dysmorphysm and mild psychomotor development delay in the absence of major malformations. Peripheral blood karyotype of the patient was 46,XX,r(9)(p24q34). G-band analysis suggested no loss of material in the ring chromosomes. FISH analysis using the subtelomere-specific sequences on chromosome 9p and 9q, revealed 46,XX,r(9)(p24q34),ish r(9)(D9S913-,D9S325+). Failure to detect any hybridization of a probe for the subtelomeric sequences in the ring 9p terminal suggested that this ring arose from breakage in the distal short arm. The cytogenetic and FISH data in our case provided further evidence for the existence of a "complete ring" phenotype with incomplete subtelomeric sequences.

Prenatal diagnosis of a de novo ring chromosome 11

A 36-year-old pregnant woman was referred for amniocentesis at 19.5 weeks gestation because of advanced maternal age and evidence of increased risk for Edward syndrome in the maternal serum screening test. Cytogenetic analysis of the cultured amniotic fluid cells revealed mosaicism for ring chromosome 11: 46,XX,r(11)[65]/45,XX,-11[16]/46,XX[34]. Parental karyotypes were normal. A targeted ultrasound showed intrauterine growth restriction (IUGR). Cordocentesis was performed to characterize the ring chromosome and to rule out tissue specific mosaicism. Karyotype was confirmed as 46,XX,r(11) (p15.5q24.2)[229]/45,XX,-11[15]. And a few new form of ring were detected in this culture. The deletion of subtelomeric regions in the ring chromosome were detected by fluorescent in situ hybridization (FISH). The pregnancy was terminated. The fetal autopsy showed a growth-retarded female fetus with rocker bottom feet. We report a case of prenatally detected a de novo ring chromosome 11.

Deficiência de hormônio do crescimento, hipotireoidismo e cromossomo 18 em anel: relato de caso / Growth hormone deficiency, hypothyroidism and ring chromosome 18: case report / Growth hormone deficiency, hypothyroidism and ring chromosome 18: case report

INTRODUÇÃO: A associação de síndrome do cromossomo 18 em anel com deficiência de hormônio de crescimento (DGH) é muito rara, com apenas dois relatos na literatura. RELATO DO CASO: Paciente feminina, negra, 1 ano de idade, encaminhada para investigação de crises de hipoglicemia desde os 6 meses, acompanhadas de crise convulsiva. Apresentava atraso do desenvolvimento neuropsicomotor e erro alimentar. Ao exame físico, criança desnutrida (escores z peso/idade de -6,95 e estatura/idade de -5,05), fenda palatina, prega epicântica e hipotonia generalizada. O diagnóstico de DGH foi feito em vigência de hipoglicemia e iniciado o tratamento com somatropina 0,1 U/kg aos 16 meses de idade. A RM do crânio evidenciou neuro-hipófise ectópica. O hipotireoidismo foi diagnosticado com 1 ano e 7 meses, sendo adicionada levotiroxina ao tratamento. O cariótipo 46XX r(18) (p11,2 ­ q.23), estabeleceu o diagnóstico de síndrome do cromossomo 18 em anel. Está em uso de GH há 3 anos, os episódios de hipoglicemia com crise convulsiva desapareceram mas não houve melhora da velocidade de crescimento. DISCUSSÃO: Não foram encontrados na literatura relatos da associação de DGH, hipotireoidismo e cromossomo 18 em anel. Crianças com cromossomo 18 em anel merecem investigação para DGH. A reposição com GH não melhorou o crescimento da nossa paciente.

INTRODUCTION: The association of 18-ring chromosome syndrome and growth hormone deficiency (GHD) is extremely rare, with only two reports in the literature. CASE REPORT: A one year-old, non-white female was referred due to hypoglycemic seizures. She had developmental delay and poor nutrition. Her physical examination was significant for a weight Z score of -6.95, height Z score of -5,05, cleft palate, epicanthic folds and generalized hypotony. Karyotype was 46XX r(18) (p11,2 ­ q.23) - 18 ring chromosome syndrome, the MRI showed an ectopic neurohypophysis. The diagnosis GHD was made due to low GH levels during spontaneous severe hypoglycemia at the age of 16 months. She was started on hGH 0.1 U/kg/day. Three months later, TSH deficiency was diagnosed and L-thyroxin therapy was started. During hGH replacement the hypoglycemic events stopped but after 3 years of hGH therapy, she did not improve growth velocity. DISCUSSION: We were unable to find any report of GHD and hypothyroidism associated with the 18-ring chromosome syndrome. Children with 18-ring chromosome should undergo investigation of GHD. In our child with 18-ring syndrome the hGH therapy did not improve growth velocity.

A Case of Ring Chromosome 13 Syndrome with Jejunal Atresia and Hearing Loss

A ring chromosome 13 was found in newborn female with multiple congenital anomalies suggestive of 13q-syndrome. She presented with intrauterine growth retardation, agenesis of thumbs, craniofacial anomalies, congenital heart diseases, CNS, gastrointestinal anomalies which are imperforate anus and jejunal atresia and sensorineural hearing loss. To our knowledge, there have been several reports on 13q-syndrome with congenital megacolon or imperforate anus at home and abroad. However, the case presenting with jejunal atresia and hearing loss has not been described previously in the country. We report this case with a brief review of the correlation between clinical features and the observed chromosome abberation.

A Case of Ring Chromosome 20 with Mental Retardation and Epilepsy / 소아과

Ring chromosome 20 mosaicism [r(20)] is a rare chromosomal anomaly associated with minor dysmorphism, mental retardation, autistic behavior, and intractable epilepsy. The proposed mechanism of ring formation is breakage of both short and long arms of a chromosome with subsequent end-to- end fusion. We encountered an 18-month-old boy who presented with developmental delay and mental retardation with seizure episodes, but showed normal brain magnetic resonance imaging. Chromosome study from peripheral blood showed 46,XY, r(20)(p13q13.3) karyotype. The authors report a case of ring chromosome 20 with mental retardation and epilepsy, with a review of the literature.