Prenatal diagnosis of the isodicentric chromosome 22 associated with cat eye syndrome by multiplex ligation-dependent probe amplification

Cat eye syndrome (CES) is a very rare chromosomal syndrome characterized by various malformations such as anal atresia, preauricular malformation, coloboma of the iris, and congenial heart and renal defects. This genetic disorder is caused by partial duplication of chromosome 22, mostly as a result of a supernumerary isodicentric marker chromosome idic(22)(q11.2). Various congenital abnormalities and extreme phenotypic variability in CES patients have been reported, which have made prenatal diagnosis of CES difficult. We report the first case diagnosed with CES prenatally by multiplex ligation-dependent probe amplification in a woman who was referred to our hospital, for a fetus presenting with heart anomaly.

Phelan-McDermid syndrome presenting with developmental delays and facial dysmorphisms / 소아과

Phelan-McDermid syndrome is a rare genetic disorder caused by the terminal or interstitial deletion of the chromosome 22q13.3. Patients with this syndrome usually have global developmental delay, hypotonia, and speech delays. Several putative genes such as the SHANK3, RAB, RABL2B, and IB2 are responsible for the neurological features. This study describes the clinical features and outcomes of Korean patients with Phelan-McDermid syndrome. Two patients showing global developmental delay, hypotonia, and speech delay were diagnosed with Phelan-McDermid syndrome via chromosome analysis, fluorescent in situ hybridization, and multiplex ligation-dependent probe amplification analysis. Brain magnetic resonance imaging of Patients 1 and 2 showed delayed myelination and severe communicating hydrocephalus, respectively. Electroencephalography in patient 2 showed high amplitude spike discharges from the left frontotemporoparietal area, but neither patient developed seizures. Kidney ultrasonography of both the patients revealed multicystic kidney disease and pelviectasis, respectively. Patient 2 experienced recurrent respiratory infections, and chest computed tomography findings demonstrated laryngotracheomalacia and bronchial narrowing. He subsequently died because of heart failure after a ventriculoperitoneal shunt operation at 5 months of age. Patient 1, who is currently 20 months old, has been undergoing rehabilitation therapy. However, global developmental delay was noted, as determines using the Korean Infant and Child Development test, the Denver developmental test, and the Bayley developmental test. This report describes the clinical features, outcomes, and molecular genetic characteristics of two Korean patients with Phelan-McDermid syndrome.

Epilepsy and Other Neuropsychiatric Manifestations in Children and Adolescents with 22q11.2 Deletion Syndrome

BACKGROUND AND PURPOSE: 22q11.2 deletion syndrome (22q11.2DS) is the most common microdeletion syndrome. Epilepsy and other neuropsychiatric (NP) manifestations of this genetic syndrome are not uncommon, but they are also not well-understood. We sought to identify the characteristics of epilepsy and other associated NP manifestations in patients with 22q11.2DS. METHODS: We retrospectively analyzed the medical records of 145 child and adolescent patients (72 males and 73 females) with genetically diagnosed 22q11.2DS. The clinical data included seizures, growth chart, psychological reports, development characteristics, school performance, other clinical manifestations, and laboratory findings. RESULTS: Of the 145 patients with 22q11.2DS, 22 (15.2%) had epileptic seizures, 15 (10.3%) had developmental delay, and 5 (3.4%) had a psychiatric illness. Twelve patients with epilepsy were classified as genetic epilepsy whereas the remaining were classified as structural, including three with malformations of cortical development. Patients with epilepsy were more likely to display developmental delay (odds ratio=3.98; 95% confidence interval=1.5-10.5; p=0.005), and developmental delay was more common in patients with structural epilepsy than in those with genetic epilepsy. CONCLUSIONS: Patients with 22q11.2DS have a high risk of epilepsy, which in these cases is closely related to other NP manifestations. This implies that this specific genetic locus is critically linked to neurodevelopment and epileptogenesis.

Linkage and Association Analyses of Schizophrenia with Genetic Variations on Chromosome 22q11 in Koreans

OBJECTIVE: Chromosome 22q11 has been implicated as a susceptibility locus of schizophrenia. It also contains various candidate genes for which evidence of association with schizophrenia has been reported. To determine whether genetic variations in chromosome 22q11 are associated with schizophrenia in Koreans, we performed a linkage analysis and case-control association study. METHODS: Three microsatellite markers within a region of 4.35 Mb on 22q11 were genotyped for 47 multiplex schizophrenia families, and a non-parametric linkage analysis was applied. The association analysis was done with 227 unrelated patients and 292 normal controls. For 39 single nucleotide polymorphisms (SNPs) spanning a 1.4 Mb region (33 kb interval) containing four candidate schizophrenia genes (DGCR, COMT, PRODH and ZDHHC8), allele frequencies were estimated in pooled DNA samples. RESULTS: No significant linkage was found at any of the three microsatellite markers in single and multi-point analyses. Five SNPs showed suggestive evidence of association (p<0.05) and two more SNPs showed a trend for association (p<0.1) in pooled DNA association analysis. Individual genotyping was performed for those seven SNPs and four more intragenic SNPs. In this second analysis, all of the 11 SNPs individually genotyped did not show significant association. CONCLUSION: The present study suggests that genetic variations on chromosome 22q11 may not play a major role in Korean schizophrenia patients. Inadequate sample size, densities of genetic markers and differences between location of genetic markers of linkage and association can contribute to an explanation of the negative results of this study.

A case of CHARGE syndrome featuring immunodeficiency and hypocalcemia

CHARGE syndrome (coloboma, heart defects, atresia choanae, retarded growth and development, genital hypoplasia, and ear abnormalities) is characterized by multiple malformations and is diagnosed using distinct consensus criteria. Mutations in the gene encoding chromodomain helicase DNA-binding protein 7 (CHD7) are the major cause of CHARGE syndrome. Clinical features of CHARGE syndrome considerably overlap those of 22q11.2 deletion syndrome. Of these features, immunodeficiency and hypocalcemia are frequently reported in patients with 22q11.2 deletion syndrome but are rarely reported in patients with CHARGE syndrome. In this report, we have described the case of a patient with typical phenotypes of 22q11.2 deletion syndrome but without the proven chromosome microdeletion. Mutation analysis of CHD7 identified a pathogenic mutation (c.2238+1G>A) in this patient. To our knowledge, this is the first case of CHARGE syndrome with immunodeficiency and hypocalcemia in Korea. Our observations suggest that mutation analysis of CHD7 should be performed for patients showing the typical phenotypes of 22q11.2 deletion syndrome but lacking the proven chromosome microdeletion.

Significance of screening chromosome 22q11.2 deletion syndrome in the congenital cardiovascular abnormalities / 国际儿科学杂志

Chromosome 22q11.2 deletion syndrome,also called DiGeorge syndrome or Velo-CardiacFacial syndrome,has all expansive phenotype involving essentially every organ and system,such as cardiovascular abnormalities,abnormal face,immunodeficiency,even psychiatric illnesses,and etc.Fluorescence in situ hybridization analysis test for the microdeletion from chromosome 22 at the q11.2 band is the comqrmed diagnostic method So far,it has not been known thoroughly in China and there has not been a normative screening system yet.Close relations between the microdeletion and congenital cardiovascular abnormalities especially conotruncal cardiac defects and arcus aortae abnormalities have been shown in reported cases.This review will describe the 22q11 DS and how to screen it in the congenital cardiovascular abnormalities so that it Can be diagnosed early and managed properly.which will benefit the patients and their later generations.

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.

Progress on chromosome 22q11 deletion syndrome / 国际儿科学杂志

Chromosome 22qll deletion syndrome(22q11DS) is a common chromosomal microdeletion syndrome. Its clinical manifestation is complex, comprising congenital heart disease, dysmorphic facial, immunodeficiency, endocrine dysfunction and so on. The syndrome has a population prevalence of approximately 1/2500-1/4000. There have been many recent advances in understanding of the clinical manifestation, behavior and psychiatric problems and the mechanisms leading to the specific phenotypic features in chromosome 22q11 deletion syndrome. Asymmetric recombination of homologous low copy repetitives in the deletion region causes the deletion of 22q11. TBX1 is the dominant gene contributing to the phenotype.

A Case of DiGeorge Syndrome With Ocular Manifestation

PURPOSE: DiGeorge syndrome (chromosome 22q11.2 deletion syndrome) is a syndrome of multiple congenital anomalies characterized by hypoplasia or aplasia of the thymus and parathyroid, cardiovascular malformation, immune deficiency, cleft palate, characteristic facial features, and hypocalcemia. Ocular findings of DiGeorge syndrome are posterior embryotoxon, retinal vascular tortuosity, strabismus, ptosis, amblyopia and tilted optic disc. The authors present a case of DiGeorge syndrome with ocular manifestation not reported previously in Korea. Case summary: A six-year old female diagnosed with DiGeorge syndrome was referred to the authors' department within the hospital. The chief complaint was blurring vision in both eyes. Best corrected visual acuity of the right eye was 0.5 and of the left eye was 0.63. Cycloplegic refraction revealed high hyperopia and astigmatism in both eyes (OD: +7.25 Dsph; -2.5 Dcyl axis 180degrees, OS: +6.25 Dsph; -3.75 Dcyl axis 180degrees). In addition, hypertelorism, ptosis and tortuous retinal vessels during fundus examination were noted. CONCLUSIONS: Upon the initial diagnosis of DiGeorge syndrome in children, a comprehensive ocular examination is necessary because other ocular conditions may exist which can affect the visual development of the patient.

A Case of Partial DiGeorge Syndrome in Prematurity

We experienced a case of partial DiGeorge syndrome in a 35+5 week premature female infant presented with micrognathia, fish-shaped mouth, beaked nose, nasal regurgitation, obstructive sleep apnea, velopharyngeal insufficiency and late onset hypocalcemic seizures. The chromosome 22q11 microdeletion was found by the FISH method. The lab findings showed serum calcium level of 4.4 mg/dL, ionized calcium level of 0.49 mg/dL, phosphorous level of 7.5 mg/dL, magnesium level of 1.3 mg/dL and PTH-RIA level of <1 pq/mL. Initial treatment was done with 10% calcium gluconate infusion and magnesium sulfate followed by oral calcium gluconate and low phosphorous- formula milk feeding. The serum calcium level was normalized in 6 days. Nasal regurgitation, desaturation with obstructive sleep apnea continued. T-cell functions and numbers(CD 3, CD 4, CD 8)were decreased but Ig G/A/M levels were normal. No visible signs of thymus shadow were seen in either chest X-ray and chest MRI. Electrocardiography and echocardiography showed normal heart. Kidney ultrasonographby showed right side mild hydronephrosis. Neurosonography was normal but EEG showed electrical partial seizure. Hearing assessment by BERA showed mild to moderate hearing impairment. Velopharyngoplasty is scheduled for further treatment. A brief review of literature was made.

Loss of heterozygosity of chromosome 22 in sporadic colorectal carcinoma / 中华消化杂志

Objective The loss of heterozygosity (LOH) on tumor suppressor genes is believed to play a key role in the carcinogenesis of colorectal cancer. When LOH occurs at a tumor suppressor gene locus where one of the alleles is already abnormal, it can result in neoplastic transformation. In this study, we analyzed the LOH on the chromosome 22 in sporadic colorectal cancer to identify additional loci involved in colorectal tumorigenesis. Methods Six polymorphic microsatellite markers were analyzed in 83 cases of colorectal cancer and normal tissue DNA by PCR. PCR products were eletrophoresed on an ABI Prism 377 DNA sequencer; Genescan 3.1 and Genotype 2.1 software were used for LOH scanning and analysis. Comparison between LOH frequency and clinicopathological data were performed by ? 2 test. Results The average LOH frequency on chromosome 22 was 27.27%. The region between markers D22S280 and D22S274 (22q12.2-q13.33) exhibited relatively high LOH frequency. The two highest LOH loci with frequencies of 35.09% and 34.04% was identified on D22S280 (22q12.2-q12.3) and D22S274 (22q13.32-q13.33). On D22S274 locus, LOH frequency of rectal cancer was 50% (9/18), which was higher than that of proximal colon cancer (12%, 2/17) ( P =0.018). The frequency of distal colon cancer was 42% (5/12), also higher than that of proximal colon cancer. But there was no statistical significance. Putting both the tumors in distal colon and rectum together into consideration, the frequency, 47% (14/30), was higher than that of proximal colon cancer ( P = 0.015 ),suggested the mechanism of carcinogenesis was different in both groups.Conclusion This study provided evidence for the involvement of putative tumor suppressor genes related to the sporadic colorectal carcinoma on chromosome 22q. The tumor suppressor gene(s) might locate on the 22q12.2-q12.3 and/or 22q13.32 -q13.33.

An Assiociation Study of Interleukin-2 Receptor beta-Chain Gene Polymorphism on Chromosome 22 in Korean Schizophrenic Patients / 신경정신의학

BACKGROUND: While a significant genetic predisposition to schizophrenia has been proposed, the mode of inheritance or nature of etiological factors is unknown. Previous reports of a genome-wide survey for schizophrenia susceptibility genes have indicated a possible region of linkage on chromosome 22. In order to test the possibility that the interleukin-2 recepto beta chain(IL-2R beta ) gene on chromosome 22 is of etiological importance in schizophrenia, a case-control association study was conducted. METHODS: Subjects were ninety-three schizophrenic patients with a diagnosis of schizophrenia by DSM- III -R criteria and ninety-seven normal controls. Schizophrenic patients were divided by clinical phenotypes such as DSM- III -R diagnostic subtypes, positive and negative symptoms, and family history so as to increase the homogeneity of schizophrenics. Genomic DNA was extracted from whole blood lymphocytes according to standard procedures. The DNA was used to study a dinucleotide repeat in the IL-2R beta gene. To reveal the dinucleotide polymorphism, genomic DNA of subjects was amplified by polymerase chain reactions(PCR). RESULTS: At the IL-2R beta gene locus, all the previously reported alleles (eight different alleles) of a dinucleotide polymorphism were identified. There was no significant difference between number of heterozygosity in schizophrenic patients and in normal controls. There was no significant difference in the distribution of frequencies of alleles between schizophrenics and normal controls. In addition, there was no significant difrfrence in the allele frequencies among subtypes of schizophrenic patients according to DSM- III -R diagnostic subtypes, positive and negative symptoms, and family history. CONCLUSIONS: The present study did not detect a difference in frequencies of alleles of a dinucleotide polymorphism at the IL-2R beta gene locus between schizophrenic patients and normal controls. These results do not support an evidence that IL-2R beta gene plays, a major role in the etiology of schizophrenia.

Loss of Heterozygosity Studies on Chromosome 9, 22 and 17p in 12 Various Pediatric Brain Tumors / 대한소아혈액종양학회지

PURPOSE: The normal function of tumor suppressor genes is thought to be related to their ability to regulate cell proliferation and the loss of such function presumably leads to malignant transformation by releasing the transformed cells from growth regulation. One approach to identify these tumor suppressor genes is by loss of heterozygosity (LOH) studies. The rationale of these studies is that the mutation of one allelic copy of a tumor suppressor gene followed by the loss of the remaining wild type allele will result in the total loss of the function of the tumor suppressor gene. Chromosomal loci with frequent LOH in malignant tumors is likely to contain tumor suppressor genes. We want to identify deletions of putative tumor suppressor gene loci in pediatric brain tumors by polymerase chain reaction (PCR)-based LOH studies using microsatellite polymorphic markers of chromosome 9, 22 and 17p as most frequent cytogenetic abnormalities involve chromosome 17p, 22 and 9 in pediatric brain tumors. MATERIAL AND METHOD: Blood and tumor samples were obtained from 12 pediatric brain tumor patients who were operated at Texas Children's Cancer Center from April 1996 to January 1997. The 12 tumors consist of 5 cases of medulloblastomas, 4 cases of juvenile pilocytic astrocytomas, and 1 case each of ependymoma, atypical teratoid rhabdoid tumor and desmoplastic infantile ganglioglioma. Genomic DNA extracted from blood and tumor tissues were amplified by PCR using [gamma-32P]ATP endlabeled primer pairs for the microsatellite polymorphic markers on chromosome 9, 22 and 17p which were D9S171, D9S169, D9S168, D9S165, D9S156, D9S110, D9S146, D9S971, D9S757,D9S176, D9S2105, D9S177, D9S2127, D9S1849, D9S1817, D22S303, D22S33, D22S315, D22S275, D22S299, D22S301, TOP1P2, PDGFB, D22S274, D22S304, D17S1866, D17S1810, D17S796, D17S1566 and D17S1574. The PCR products were separated by electrophoresis in a denaturing 6% polyacrylamide gel and exposed on X-ray films to analyze LOH. RESULTS: 1) There was no evidence of LOH on chromosome 9 in all 12 pediatric brain tumors. 2) Among 12 pediatric brain tumors, only one allelic loss on chromosome 22 (D22S274 : 22q13.31-22q13.33) was observed in an atypical teratoid rhabdoid tumor. 3) LOH for loci on chromosome 17p were detected in 6 cases (50%) of 12 various pediatric brain tumors including 4 cases of medulloblastomas and 1 case each of ependymoma and atypical teratoid rhabdoid tumor. Among 5 cases of medulloblastomas, 4 cases(80%) showed LOH on at least one of 5 markers of chromosome 17p. 4) There was no allelic loss on chromosome 9, 22 and 17p in juvenile pilocytic astrocytomas. CONCLUSION: Our data indicate that there may be a putative tumor suppressor gene located on chromosome 22q13.3 associated with tumorigenesis of atypical teratoid rhabdoid tumor, and other putative tumor suppressor genes located on chromosome 17p13.1-17p13.3 associated with tumorigenesis of medulloblastoma, ependymoma and atypical teratoid rhabdoid tumor. But we need to collect more pediatric brain tumor samples to be studied and allelotype the suggested LOH region in detail.

Clinical Features and Molecular Diagnosis of CATCH-22 Syndrome

BACKGROUND: CATCH-22 syndrome is a common genetic disorder with features of cardiac defect, abnormal face, thymic hypoplasia, cleft palate, and hypocalcemia, along with microdeletion at chromosome 22. This study is to report twelve Korean patients with CATCH-22 syndrome diagnosed by the fluorescent in situ hybridization (FISH) method. METHOD: Clinical features were analyzed according to the FISH result and the Southern blot analysis using new probes DGCR680 and pDH-1 was performed to correlate with the clinical findings and FISH results. Twelve patients were studied by FISH method and eight of them were studied by Southern blot analysis. RESULTS: Seven patients had typical facial features for CATCH-22 syndrome, but five patients had equivocal face, although they were originally suspected to have the conotruncal face. The main cardiac lesion of eight patients were tetralogy of Fallot (TOF) and seven of them had pulmonary atresia. Two cases had other anomalies in the ventricular outflow tract, being common arterial trunk or pulmonary stenosis. Two cases had a patent arterial duct or atrial septal defect (ASD). All of twelve patients had positive result on FISH study. Among eight patients with positive FISH study, six cases were positive for Southern blot analysis. CONCLUSION: We conclude that CATCH-22 syndrome has variable facial, cardiac and genetic features, and the combined use of probes is recommended for a more accurate diagnosis.