Segregation of a familial balanced (12;10) insertion resulting in dup(10)(q21.2q22.1) and del(10)(q21.2q22.1) in first cousins

An interchromosomal insertion in 3 generations of a family was ascertained through two developmentally delayed first cousins. Cytogenetic analysis using G-banding and chromosome painting showed an apparently balanced direct insertion of chromosome 10 material into chromosome 12, ins(12;10)(q15;q21.2q22.1), in the mothers and grandfather of these children. The proposita inherited only the derivative 10 chromosome, resulting in deletion of 10q21.2 → 22.1 while her cousin inherited only the derivative 12, resulting in duplication of 10q21.2 → 22.1. A comparison of the proposita with published deletion cases suggests a pattern of anomalies attributable to deletion of the 10q21 → q22 region: developmental delay, hypotonia, a heart murmur, telecanthus, broad nasal root and ear abnormalities. This is the first report of a nontandem duplication of the 10q21 → q22 region. The phenotype of the cousin with the duplication does not overlap greatly with published tandem 10q duplications. Finally, this report reaffirms the importance of obtaining family studies of patients with interstitial chromosomal abnormalities. Am J. Med. Genet. 69:188–193, 1997. © 1997 Wiley-Liss, Inc.     

Familial dup(5)(q15q21) associated with normal and abnormal phenotypes

We studied a familial dup(5q) present in a phenotypically normal father and his monozygotic twin daughters with different abnormal phenotypes. High-resolution chromosome analysis suggested that the duplicated segment was of region q15-21, which seems to be the smallest dup(5q) reported thus far. This dup(5q) was confirmed by fluorescence in situ hybridization with a chromosome 5 painting library and 5q cosmid clones. The presence of the dup(5q) in a normal father suggested that the duplication itself may be harmless. The anomalies in the twins may be due to processes other than this chromosome change. Am. J. Med. Genet. 75:75–77, 1998. © 1998 Wiley-Liss, Inc.     

15q24.1 BP4-BP1 microdeletion unmasking paternally inherited functional polymorphisms combined with distal 15q24.2q24.3 duplication in a patient with epilepsy,psychomotor delay,overweight, ventricular arrhythmia

15q24 microdeletion and microduplication syndromes are genetic disorders caused by non-allelic homologous recombination between low-copy repeats (LCRs) in the 15q24 chromosome region. Individuals with 15q24 microdeletion and microduplication syndromes share a common 1.2 Mb critical interval, spanning from LCR15q24B to LCR15q24C. Patients with 15q24 microdeletion syndrome exhibit distinct dysmorphic features, microcephaly, variable developmental delay, multiples congenital anomalies while individuals with reciprocal 15q24 microduplication syndrome show mild developmental delay, facial dysmorphism associated with skeletal and genital abnormalities. We report the first case of a 10 year-old girl presenting mild developmental delay, psychomotor retardation, epilepsy, ventricular arrhythmia, overweight and idiopathic central precocious puberty. 180K array-CGH analysis identified a 1.38 Mb heterozygous interstitial 15q24.1 BP4-BP1 microdeletion including HCN4 combined with a concomitant 2.6 Mb heterozygous distal 15q24.2q24.3 microduplication. FISH analysis showed that both deletion and duplication occurred de novo in the proband. Of note, both copy number imbalances did not involve the 1.2 Mb minimal deletion/duplication critical interval of the 15q24.1q24.2 chromosome region (74.3–75.5 Mb). Sequencing of candidate genes for epilepsy and obesity showed that the proband was hemizygous for paternal A-at risk allele of BBS4 rs7178130 and NPTN rs7171755 predisposing to obesity, epilepsy and intellectual deficits. Our study highlights the complex interaction of functional polymorphisms and/or genetic variants leading to variable clinical manifestations in patients with submicroscopic chromosomal aberrations.     

Partial trisomy of chromosome 6q: An interstitial duplication of the long arm

We report on a 5-year-old girl with a de novo interstitial duplication of chromosome 6q21-q23 and delayed development and speech with distinctive minor facial anomalies including a “carp” mouth. Fluorescence in situ hybridization using a chromosome 6 paint probe confirms that the extra material is of chromosome 6 origin. This further delineates the dup(6q) syndrome and the manifestations due to the specific duplicated chromosomal region involved. Am. J. Med. Genet. 80:133–135, 1998. © 1998 Wiley-Liss, Inc.     

Ebstein anomaly associated with rearrangements of chromosomal region 11q

Ebstein anomaly (EA) is a relatively uncommon congenital heart defect and it is very rarely associated with a chromosomal anomaly. We report two distinct rearrangements of the chromosomal region 11q arm in two unrelated patients with Ebstein anomaly, renal malformation, minor anomalies, and the Pierre Robin sequence. The first patient had an interstitial deletion of chromosome 11 [46,XY,del(11)(11q21q23), and the other had a tertiary trisomy of chromosome 11qter (47,XX,+der(22)t(11;22)(q23; q11.2) Its association with either a chromosome 11q deletion or a duplication in some individuals suggests that a rearrangement of the 11q region is likely to cause a shift of the individuals' underlying liability to develop EA above a certain threshold. Am. J. Med. Gen. 80:157–159, 1998. © 1998 Wiley-Liss, Inc.     

Duplication 14(q24.3q31) in a father and daughter: Delineation of a possible imprinted region

A number of clinical reports have described children with a variety of congenital anomalies in association with uniparental disomy (upd) of chromosome 14, suggesting that at least some genes on chromosome 14 are subject to parent of origin, or imprinting, effects. However, little else is known about this putative imprinting of chromosome 14. Both maternal and paternal upd have been observed, but a consistent phenotype has only been suggested for the former. Here we report on a child with developmental delay, microcephaly, distinct facial findings, and who has a duplication of 14q24.3q31. The same cytogenetic abnormality was found in her phenotypically normal father. We hypothesize that this segment of chromosome 14 contains maternally silenced genes, and that this duplicated segment defines an imprinted region on chromosome 14. Alternatively, this cytogenetic duplication may be unrelated to the girl's phenotypic anomalies, and this duplication may contain genes that are not subject to dosage effect. Am. J. Med. Genet. 71:361–365, 1997. © 1997 Wiley-Liss, Inc.     

Proximal trisomy 1q in a girl with developmental delay and minor anomalies

We report on a girl with developmental delay, macrocephaly, facial asymmetry, small downturned palpebral fissures, high and narrow palate, micrognathia, short neck, a heart defect, and unilateral renal agenesis. Cytogenetic analysis showed a proximal tandem duplication of the long arm of chromosome one (1q12→q21.3). This abnormality was suggested by G- and C-banding but it was specifically characterized by fluorescent in situ hybridization (FISH). Clinical findings in our patient are compared with those of the literature in an attempt to delineate the phenotype in patients with proximal 1q duplication. © 1996 Wiley-Liss, Inc.     

Duplication of (2)(q11.1‐q13.2) in a boy with mental retardation and cleft lip and palate: Another clefting gene locus on proximal 2q?

A 4‐year‐old boy with left cleft lip and cleft palate, multiple minor anomalies and developmental delay revealed an abnormal chromosome 2 with enlarged proximal long arm, de novo, in his karyotype. Fluorescence in situ hybridization with a chromosome 2 library and band‐specific YACs confined the duplicated segment to 2q11.1‐q13.2 and indicated a direct tandem duplication due to unbalanced crossover between chromatids. © 2002 Wiley‐Liss, Inc.     

17p11.2p12 triplication and del(17)q11.2q12 in a severely affected child with dup(17)p11.2p12 syndrome

Multiple congenital anomalies/mental retardation syndromes due to genomic rearrangements involving chromosome 17p11.2 include deletion resulting in Smith-Magenis syndrome and a reciprocal duplication of the same region resulting in the 17p11.2 duplication syndrome. We present the clinical and molecular analysis of an 8-year-old male with a dup(17p11.2p12) who was evaluated for unusual severity of the phenotype. Fluorescent in situ hybridization (FISH) analysis not only confirmed the 17p duplication but also identified an approximately 25% mosaicism for tetrasomy 17p11.2p12. Whole-genome array comparative genomic hybridization (aCGH) was performed to identify other genomic rearrangements possibly contributing to the severe phenotype and the unusual features in the patient. The 17p duplication was determined by FISH and aCGH to encompass approximately 7.5 Mb, from COX10 to KCNJ12. An approximately 830 Kb deletion of 17q11.2q12, including exon 1 of an amiloride-sensitive cation channel neuronal gene, ACCN1, was also identified by aCGH; breakpoints of the deletion were confirmed by FISH. Sequencing the non-deleted allele of ACCN1 did not show any mutations. Western analysis of human tissue-specific proteins revealed that ACCN1 is expressed not only in the brain as previously reported but also in all tissues examined, including heart, liver, kidneys, and spleen. The large-sized 17p11.2p12 duplication, partial triplication of the same region, and the 17q11.2q12 deletion create a complex chromosome 17 rearrangement that has not been previously identified. This is the first case of triplication reported for this chromosome. Our study emphasizes the utility of whole-genome analysis for known cases with deletion/duplication syndromes with unusual or severe phenotypes.     

Small terminal deletion of 1p and duplication of 1q: Cytogenetics,FISH studies,and clinical observations at newborn and at age 16 years

A small, extra chromosome segment added to 1p was found by Q-banding 16 years ago in a newborn baby with low birth weight, short stature, wide open fontanelle, small palpebral fissures, depressed nose bridge, and inguinal hernia. This chromosome abnormality has been characterized recently with G-banding and fluorescence in situ hybridization using multiple DNA probes. The karyotype is now described as 46,XY, der(1)(qter→p36.13::q42.3→qter), representing a small deletion of 1p36.13-pter and a small duplication of 1q42.3-qter. Re-examination of this patient at age 16 years showed marked psychomotor delay, severely accentuated dorsal kyphosis and scoliosis, pectus excavatum, and other anomalies but no clinical signs of neuroblastoma. Comparison of the clinical findings in this case with those described in the patients having either a deletion of 1p36-pter or a duplication of 1q42-qter further illustrated the complexity of the genotype-phenotype relationship. Am. J. Med. Genet. 86:118–123, 1999. © 1999 Wiley-Liss, Inc.     

Inv dup del (1)(pter→q44::q44→q42:) with the classical phenotype of trisomy 1q42–qter

We report on a girl with a trisomy 1q42–q44 due to an inverted duplication of this region, associated with a terminal deletion of the long arm of the rearranged chromosome 1. Both the large duplication (more than 30 cM) and the small deletion were detected by FISH. Complete karyotype was: (46,XX, inv dup(1)(q44q42).ish(dup del 1)(q44q42)(D1S446×2, D1S423×2, tel1q‐). The phenotype of the patient is characterized by macrocephaly with prominent forehead, downslanting palpebral fissures, micrognathia, and psychomotor retardation. All these clinical features are the same as observed for the typical trisomy 1q42–qter syndrome. The phenotypic effects of the inversion and the terminal deletion of 1q in addition to the trisomy are discussed here. © 2001 Wiley‐Liss, Inc.     

FISH characterization of a supernumerary r(1)(::cen→q22::q22→sq21::) chromosome associated with multiple anomalies and bilateral cataracts

We describe the case of a 15‐year‐old girl with multiple congenital anomalies, dysmorphic features, severe kyphoscoliosis, growth and mental retardation, and the absence of speech, in whom 35% of the cells carried a supernumerary ring chromosome 1. Fluorescence in situ hybridization (FISH) analysis using YAC/BAC clones spanning the region from 1p13 to 1q21 made it possible to determine the genomic content and structure of the ring(1), which was found to consist of the cytogenetic bands 1q21–22. A complex structure was delineated in the ring chromosome with a partial inverted duplication delimited by markers WI‐7732 and WI‐607, with WI‐7396 and WI‐8386 being the boundaries of the single copy segment. Comparison of the clinical signs of other patients with mosaic r(1) reported in the literature allowed the identification of a patient sharing a number of clinical signs including cataracts. Given that mutations of the GJA8 gene encoding connexin 50 (Cx50) and mapping to 1q21 have been associated with the presence of cataracts, it is possible that a gain in copy number or a rearrangement of GJA8 may contribute to cataractogenesis.     

Pure familial 6q21q22.1 duplication in two generations

Familial transmissions of unbalanced chromosomal abnormalities are rare. We report here the first case of a maternally inherited pure partial duplication of the long arm of chromosome 6 [46,XX,dup(6)(q21q22.1)mat]. The proband was referred for karyotyping as she presented intrauterine growth retardation (IUGR), moderate mental retardation and facial dysmorphism. Molecular cytogenetics analysis with various BACs showed a duplication of 5-10 Mb between 6q21 and 6q22.1. The proband's mother was found to have the same chromosome abnormality and a similar phenotype, but less severe dysmorphism. This variability in clinical findings between generations may have several causes, including attenuation with aging, imprinting or mosaicism. Only three other cases of pure partial 6q duplication similar to that of our case have been reported. The available information for all four cases was used to refine the karyotype-phenotype correlations for duplications of the 6q21q22 segment.     

Duplication of 5ql1.2→q13.1 from a familial (5;20) balanced insertion

A 2-year-old boy with gross motor delay and few minor anomalies has a pure duplication of a small segment of chromosome 5q11.2→q13.1. A balanced insertion of this 5q segment into chromosome 20q proximal to the centromere has been found in his father, uncle, and paternal grandmother.     

Comprehensive review of the duplication 3q syndrome and report of a patient with Currarino syndrome and de novo duplication 3q26.32‐q27.2

Partial duplications of the long arm of chromosome 3, dup(3q), are a rare but well‐described condition, sharing features of Cornelia de Lange syndrome. Around two thirds of cases are derived from unbalanced translocations, whereas pure dup(3q) have rarely been reported. Here, we provide an extensive review of the literature on dup(3q). This search revealed several patients with caudal malformations and anomalies, suggesting that caudal malformations or anomalies represent an inherent phenotypic feature of dup(3q). In this context, we report a patient with a pure de novo duplication 3q26.32‐q27.2. The patient had the clinical diagnosis of Currarino syndrome (CS) (characterized by the triad of sacral anomalies, anorectal malformations and a presacral mass) and additional features, frequently detected in patients with a dup(3q). Mutations within the MNX1 gene were found to be causative in CS but no MNX1 mutation could be detected in our patient. Our comprehensive search for candidate genes located in the critical region of the duplication 3q syndrome, 3q26.3‐q27, revealed a so far neglected phenotypic overlap of dup(3q) and the Pierpont syndrome, associated with a mutation of the TBL1XR1 gene on 3q26.32.     

Interstitial deletion 2q14q21

A girl with multiple congenital anomalies and a tendency to severe pyogenic infections was found to have an interstitial deletion of chromosome band 2q14-q21. Unusual facial manifestations included enophthalmos, long philtrum, micrognathia, narrow forehead, prominent glabella, and depressed nasal bridge. Unilateral corneal clouding, with Peters-like anomaly; agenesis of the corpus callosum; brain atrophy; and heart, kidney, hand, and dermatoglyphic anomalies were additional findings. Eye anomalies were observed in five of 22 patients with deletions of chromosome 2q. In comparing these cases, it seems that deletions of bands 2q21 and 2q31 are variably associated with microphthalmia, corneal clouding, cataracts, and Peters anomaly. Measurement of protein C and interleukin-1 (IL-1) did not show a gene dose effect, but the pyogenic infections and low IgA found in this patient may reflect an abnormality of IL-1 not detectable by our methods.     

De novo 46,XX, dir dup (11)(q13.3→q14.2) in a patient with mental retardation, congenital cardiopathy and thrombopenia

A 31-year-old female is reported with mild to moderate mental retardation, facial dysmorphy, congenital cardiopathy, and mild thrombocytopenia as the most important clinical findings. Chromosome analysis in lymphocytes showed a de novo dir dup (11)(q13.3→14.2), by both G-banding and FISH techniques. Previously reported constitutional duplications of 11q are mostly the result of unbalanced translocations involving chromosome 11q, and are associated with a partial monosomy or trisomy of the translocation partner chromosome. In case of an unbalanced translocation it is not clear which clinical findings result from the chromosome 11 duplication and which result from the abnormality on the translocation partner chromosome. This is the first report on a constitutional duplication of chromosome region 11q13.3→14.2 without involvement of other chromosomes.     

15q duplication associated with autism in a multiplex family with a familial cryptic translocation t(14;15)(q11.2;q13.3) detected using array-CGH

Autism spectrum disorders (ASDs) are a group of neurodevelopmental disorders with a strong genetic aetiology. In approximately 1% of cases, duplication of the 15q11-13 region has been reported. We report the clinical, array-comparative genomic hybridization (CGH) and cytogenetic evaluation of two individuals from a multiplex family demonstrating autism due to a maternally inherited gain of 15q11-13. Our findings indicate that unlike most 15q11-13 gains, which are caused by interstitial duplication of this region or supernumerary marker chromosomes deriving from proximal 15q, the 15q gain in this family is the result of abnormal segregation of a cryptic familial translocation with breakpoints at 14q11.2 and 15q13.3. The affected members of this family were found to have a normal karyotype at >550 band resolution. This translocation was identified using the 1-Mb resolution whole genome array (Spectral Genomics). The affected individuals have a gain of seven clones from proximal 15q, a loss of two clones from proximal 14q and a gain of two clones from 6q. Fluorescent in situ hybridization (FISH) analysis with clones from chromosomes 14 and 15, combined with DAPI reverse banding, showed an abnormal karyotype with one normal chromosome 15 and the der(15) t(14;15)(q11.2.;q13.3), resulting in the gain of proximal 15q and the loss of proximal 14q in affected individuals. The duplication of two clones from 6q in the affected subjects was also found in unaffected members of the family. Our findings suggest that the gain of 15q in autism may in some cases be due to cryptic translocations with breakpoints in the pericentromic regions of chromosome 15 and a different acrocentric chromosome. Variation in the size of pericentromic regions of any acrocentric chromosome may justify karyotype and FISH studies of autistic probands and their parents using probes from the 15q proximal region to determine recurrence risk for autism in some families.     

Malformation syndrome of duplication 12q24.1→qter

While duplication and deletion of the short arm of chromosome 12 cause well-recognized syndromes, duplication of the long arm of chromosome 12 is rarely observed. We are reporting a duplication of chromosome 12 distal to band q24.1 in a five-month-old child. His chromosome constitution is 46,XY,-4, + der(4),t(4:12)(p16;q24.1)mat. The balanced translocation is also carried by his maternal grandmother and two of the mother's brothers. The malformation syndrome consisted of unusual facial appearance and anomalies of the musculoskeletal, cardiovascular, genitourinary, and central nervous systems. Four previously reported patients had similar break points on chromosome 12 with similar malformations; therefore, phenotype-karyotype correlation suggests a definitive malformation syndrome associated with duplication of chromosome region 12q24.1→qter.     

多发性骨髓瘤1q染色体异常与13q缺失的相关性研究

目的 探讨多发性骨髓瘤(multiple myeloma,MM)中13q14的缺失[del(13q14)]和1q染色体异常的相关性.方法 应用CD138单克隆抗体磁珠分选系统纯化48例初治MM患者的骨髓浆细胞,结合SpectrumorangeTM直接标记的位于13q14和1q12的序列特异性DNA探针和间期荧光原位杂交技术检测48例MM患者del(13q14)及1q染色体异常情况.结果 48例MM患者中,用D13S319探针检测,del(13q14)异常22例(45.8%);用CEP1探针检测.23例(47.9%)发现1q染色体异常.其中2例为1q缺失,21例为1q重复.22例伴有del(13q14)MM患者中16例出现1q染色体异常;26例未检测到del(13q14)MM患者中仅7例发现1q染色体异常.经X2检验两者间差异有统计学意义(X2=10.02,P＜0.01).结论 del(13q14)及1q染色体异常在MM中的发生率较高,两者间存在高度相关性.