1.Unbalanced subtelomic rearrangement involving 9q and 22q in a child with mental retardation and multiple congenital anomalies.
Bing XIAO ; Ya XING ; Xing JI ; Yan XU ; Lin NI ; Yue ZHU ; Jiong TAO
Chinese Journal of Medical Genetics 2013;30(6):666-669
OBJECTIVETo determine genetic cause for a patient with development delay and multiple congenital anomalies.
METHODSRoutine karyotype analysis was performed for the patient and his parents. Array comparative genomic hybridization (array CGH) was performed for the patient to detect cryptic chromosome aberration.
RESULTSKaryotype analysis revealed no obvious anomaly for the patient and his parents. Array CGH has detected a 2.8 Mb heterozygous deletion at 9q34.3 and an 8.1 Mb heterozygous duplication at 22q. Fluorescence in situ hybridization analysis of the patient revealed an unbalanced subtelomeric translocation 46, XY, der(9) t(9; 22) (q34.3; q13.2q13.33) mat, which has resulted in partial trisomy 22q and partial monosomy 9q. Clinical features of the patient included developmental delay, facial dysmorphism and multiple congenital anomalies. Upon subsequent pregnancy, FISH analysis revealed that the fetus has inherited the normal chromosomes 9 and 22 from his mother. Postnatal follow-up confirmed normal development milestone and physiques in the child.
CONCLUSIONAn unbalanced translocation involving 9q and 22q has been found in a child featuring multiple congenital anomalies, which is due to a balanced translocation 9; 22 in his mother. Array CGH and FISH have also helped with discovery of subtelomeric rearrangement. Prenatal diagnosis of this aberration in subsequent pregnancies with FISH can prevent the recurrence of this disease.
Abnormalities, Multiple ; genetics ; Chromosomes, Human, Pair 22 ; Chromosomes, Human, Pair 9 ; Female ; Humans ; Infant ; Intellectual Disability ; genetics ; Male ; Translocation, Genetic
2.Ring 22 chromosome syndrome induced azoospermia: a case report and literature review.
Yan-Wei SHA ; Lu DING ; Yue-Qiang SONG ; Yun-Sheng GE ; Huan ZENG ; Ping LI
National Journal of Andrology 2012;18(12):1111-1114
OBJECTIVETo investigate the clinical phenotype and genetic characteristics of an azoospermia patient with ring 22 chromosome syndrome.
METHODSWe analyzed the clinical data of an azoospermia patient with ring 22 chromosome syndrome and reviewed relevant literature.
RESULTSThe patient was a short 29-year-old male, with bilateral testes small in size and soft in texture. Seminal examination indicated azoospermia. Chromosome analysis showed the karyotype of the patient to be 46, XY, r (22) (p11, q25). The level of testosterone was low, and the testicular tissue was brittle and easy to break. Pathological microscopy revealed reduced number of Sertoli cells and germ cells in the seminiferous tubules and thinner layers of cells. All the germ cells were spermatogonia. Neither spermatocytes nor sperm cells were found, which suggested complete spermatogenic failure. Mild interstitial fibrosis was visible in part of the seminiferous tubule walls.
CONCLUSIONPatients with ring 22 chromosome syndrome usually represent normal clinical phenotypes. However, this kind of genetic abnormality often induces severe testicular damage and spermatogenic arrest, which may result in azoospermia.
Adult ; Azoospermia ; etiology ; genetics ; Chromosomes, Human, Pair 22 ; Humans ; Male ; Oligospermia ; Ring Chromosomes ; Spermatogenesis ; Spermatogonia ; Syndrome
8.Another grey zone for clinical genetics: chromosomal microduplication 22q11.2.
Chinese Journal of Medical Genetics 2007;24(5):551-555
Theoretically, microduplication of chromosomal region 22q11.2, which is rich in segmental duplications, should be as frequent as microdeletions of the same region. Preliminary analysis on the rarity of reports for 22q11.2 microduplication in the literature has suggested that, for the discovery of 22q11.2 microduplication, there has been a lack of sensitivity for routine diagnostic techniques such as karyotyping, PCR and FISH. On the other hand, the diverse anomalies and extremely variable phenotypes of carriers also implied great difficulties one has to face upon clinical consultation. Genetics as well as clinical problems in connection with 22q11.2 microduplication has vividly illustrated the great challenge for the interpretation of genotype-phenotype correlation, and thereby posed yet another gray zone for clinical genetics research.
Chromosome Deletion
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Chromosomes, Human, Pair 22
;
genetics
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Gene Duplication
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Genetics, Medical
;
Humans
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Phenotype
9.The relationship between physical distance and genetic distance on chromosome 22.
Jianpin TANG ; Yiping HOU ; Yingbi LI ; Jin WU ; Jian ZHANG
Chinese Journal of Medical Genetics 2002;19(3):187-189
OBJECTIVETo construct a genetic map based on data from the Chinese population in northern part of China and to compare relationship between physical distance and genetic distance on chromosome 22.
METHODSPCR amplification was employed to genotype 6 STR loci on chromosome 22, and pedigree analysis was performed.
RESULTSA genetic map of Chinese Han population in the northern part of China was constructed and a preliminary comparison of the physical and genetic distances between 6 STR loci on chromosome 22 was made.
CONCLUSIONThere is complex relationship between genetic distance and physical distance: the distance between STR loci is related to physical distance but also recombination fraction, and there are differences of the genetic and physical distances on chromosome 22 between Chinese and Caucasian, and between the male and female.
China ; Chromosome Mapping ; Chromosomes, Human, Pair 22 ; genetics ; Female ; Genotype ; Humans ; Male ; Microsatellite Repeats ; genetics ; Pedigree
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