11p15 duplication and 13q34 deletion with Beckwith–Wiedemann syndrome and factor VII deficiency

Here we report a patient with 11p15.4p15.5 duplication and 13q34 deletion presenting with Beckwith–Wiedemann syndrome (BWS) and moderate deficiency of factor VII (FVII). The duplication was initially diagnosed on methylation‐sensitive multiplex ligation‐dependent probe amplification. Array comparative genome hybridization confirmed its presence and indicated a 13q34 distal deletion. The patient's clinical symptoms, including developmental delay and facial dysmorphism, were typical of BWS with paternal 11p15 trisomy. Partial 13q monosomy in this patient is associated with moderate deficiency of FVII and may also overlap with a few symptoms of paternal 11p15 trisomy such as developmental delay and some facial features. To our knowledge this is the first report of 11p15.4p15.5 duplication associated with deletion of 13q34 and FVII deficiency. Moreover, this report emphasizes the importance of detailed clinical as well as molecular examinations in patients with BWS features and developmental delay.     

Hypocalcemia impacts heart failure control in DiGeorge 2 syndrome

Chromosome 10p terminal deletion accounts for a rare subset among patients presenting with DiGeorge syndrome, and is designated as DiGeorge 2 syndrome. We report a neonate with DiGeorge-like phenotype having a deletion of distal 10p (p13-pter) and a duplication of terminal 3q (q29-qter) derived from paternal balanced translocation between 3q29 and 10p13. She had facial dysmorphism, atrial and ventricular septal defect, impaired T-cell function, hypoparathyroidism, sensorineural hearing loss, renal abnormalities and developmental delay. Her phenotype corresponded well with the typical characteristics of partial monosomy 10p and the small duplication of terminal 3q did not involve the critical region of 3q duplication syndrome. Clinically, hypoparathyroidism-related hypocalcemia lasted for three weeks and resulted in repeated episodes of heart failure. It was not until the calcium level was normalized that her heart failure improved markedly.
Conclusion: Cytogenetic analysis can help to recognize patients early on who have terminal 10p deletion when microdeletion of 22q11.2 is not the cause of DiGeorge syndrome. Hypoparathyroidism-related hypocalcemia impacts heart failure control in partial monosomy 10p and should be managed aggressively on critical care.     

Microarray analysis of unbalanced translocation in Wolf‐Hirschhorn syndrome

Wolf–Hirschhorn syndrome (WHS) is caused by deletions involving chromosome region 4p16.3, which is characterized by growth delay, mild‐to‐severe mental retardation, hypotonia, facial dysmorphisms and shows extensive phenotypic variability include feeding difficulties, epilepsy and congenital anomalies. Variation in the size of the deletion involving chromosome region 4p16.3 may explain the clinical variation. However, previous studies indicate that duplication for another chromosome region due to an unbalanced translocation elucidate approximately 40–45% WHS patients. Therefore, we used whole genomic cytogenetics array to analyze the entire genome at a significantly higher resolution over conventional cytogenetics to characterize the exact subtelomeric aberration region of one patient with developmental delay and several facial characteristics reminiscent Wolf–Hirschhorn syndrome. Here we report that our patient had 3.7 Mb deletion at the 4p16.2 and 6.8 Mb duplication at 8p23.1 resulted from the unbalanced translocations der(4)t(4;8)(p16.2;p23.1). We confirmed that our patient with monosomy 4p16.2 which is consistent with Wolf–Hirschhorn syndrome and trisomy 8p23.1. The combination of the 4p deletion with 8p partial trisomy explains the complex phenotype presented by our patient.     

Patient with terminal 9 Mb deletion of chromosome 9p: Refining the critical region for 9p monosomy syndrome with trigonocephaly

We describe a patient with typical manifestations of 9p monosomy syndrome, including trigonocephaly and sex reversal. Array comparative genomic hybridization (CGH) revealed a 9p terminal deletion of approximately 9 Mb with the breakpoint at 9p23. We compared the deleted segments of 9p associated with reported cases of 9p monosomy syndrome with trigonocephaly. We did not identify a region that was shared by all patients; however, when only pure terminal or interstitial deletions that did not involve material from any other chromosome were compared, we identified a segment from D9S912 to RP11‐439I6 of approximately 1 Mb that was deleted in every patient. We propose that this 1‐Mb segment might be the critical region for 9p monosomy syndrome with trigonocephaly.     

1p36 deletion syndrome associated with Prader–Willi‐like phenotype

Background: 1p36 deletion syndrome is one of the most common subtelomeric deletion syndromes, characterized by moderate to severe mental retardation, characteristic facial appearance, hypotonia, obesity, and seizures. The clinical features often overlap with those of Prader–Willi syndrome (PWS). To elucidate the phenotype–genotype correlation in 1p36 deletion syndrome, two cases involving a PWS‐like phenotype were analyzed on molecular cytogenetics. Methods: Two patients presenting with the PWS‐like phenotype but having negative results for PWS underwent fluorescence in situ hybridization (FISH). The size of the chromosome 1p36 deletions was characterized using probes of BAC clones based on the University of California, Santa Cruz (UCSC) Genome Browser. Results: PWS was excluded on FISH and methylation‐specific polymerase chain reaction. Subsequent FISH using the probe D1Z2 showed deletion of the 1p36.3 region, confirming the diagnosis of 1p36 deletion syndrome. Further analysis characterized the 1p36 deletions as being located between 4.17 and 4.36 Mb in patient 1 and between 4.89 and 6.09 Mb in patient 2. Conclusion: Patients with 1p36 deletion syndrome exhibit a PWS‐like phenotype and are therefore probably underdiagnosed. The possible involvement of the terminal 4 Mb region of chromosome 1p36 in the PWS‐like phenotype is hypothesized.     

一例13号环状染色体综合征患儿的临床及遗传学分析

患儿,女,5个月,因生长发育迟缓就诊,体格检查发现体格发育落后,特殊面容（小头畸形、眼距宽、耳位偏低、鼻梁扁平、短人中）以及一侧小阴唇缺失。外周血染色体核型为46,XX,r（13）（p11q33）[82]/45,XX,-13[10]/46,XX,r（13;13）（p11q33;p11q33）[8];微阵列比较基因组杂交（aCGH）检测显示13q11q33.2区域和13q33.2q34区域分别有87.5 Mb的重复和8.2 Mb的缺失;荧光原位杂交（FISH）显示13号环状染色体长臂末端缺失。诊断为13号环状染色体综合征。该综合征临床表型多变,主要与染色体区带中遗传物质丢失的数量、部位以及不同核型嵌合比例不同等密切相关。     

Monosomy 1p36 – A multifaceted and still enigmatic syndrome: Four clinically diverse cases with shared white matter abnormalities

Monosomy 1p36 is the most common subtelomeric deletion syndrome seen in humans. Uniform features of the syndrome include early developmental delay and consequent intellectual disability, muscular hypotonia, and characteristic dysmorphic facial features. The gene-rich nature of the chromosomal band, inconsistent deletion sizes and overlapping clinical features have complicated relevant genotype–phenotype correlations. We describe four patients with isolated chromosome 1p36 deletions. All patients shared white matter abnormalities, allowing us to narrow the critical region for white matter involvement to the deletion size of up to 2.5 Mb from the telomere. We hypothesise that there might be a gene(s) responsible for myelin development in the 1p36 subtelomeric region. Other significant clinical findings were progressive spastic paraparesis, epileptic encephalopathy, various skeletal anomalies, Prader-Willi-like phenotype, neoplastic changes – a haemangioma and a benign skin tumour, and in one case, sleep myoclonus, a clinical entity not previously described in association with 1p36 monosomy. Combined with prior studies, our results suggest that the clinical features seen in monosomy 1p36 have more complex causes than a classical contiguous gene deletion syndrome.     

A 10q21.3q22.2 microdeletion identified in a patient with severe developmental delay and multiple congenital anomalies including congenital heart defects

Interstitial deletions in the 10q21.3q22.2 chromosomal region are rare. A de novo microdeletion in this region was identified in a patient with severe developmental delay and multiple congenital anomalies, including congenital heart defects. The identified 10.4‐Mb deletion included 84 RefSeq genes. CTNNA3 and JMJD1C have been associated with cardiomyopathy and neurological impairments (autism and/or intellectual disability), respectively. Because there is no gene which shows one‐to‐one relation to clinical features observed in this patient, combinatory deletion of the genes in this region would be causative of the clinical features in this patient.     

Clinical manifestation of chromosome 2 long arm terminal deletion--presentation of four cases

Terminal deletion of the long arm of chromosome 2 belongs to the most common structural aberrations of subtelomeric chromosomal regions. Clinical manifestations of this syndrome comprise: global psychomotor delay, moderate to severe mental retardation with specific facial dysmorphism. In some cases a phenotype similar to Albright's hereditary osteodystrophy (AHO) may also be observed (short stature, obesity, brachydactyly). The paper covers the characteristics of clinical features in four cases of terminal deletions in 2q36.2, 2q37.1 and 2q37.3 identified in routine cytogenetic study and fluorescent in situ hybridization (FISH) technique. In one case the deletion of subtelomeric region of chromosome 2 (2q37.3) occurred as a result of reciprocal translocation between chromosomes 2 and 7. A comparison was made of clinical symptoms present in our patients with relevant data concerning other cases of 2q monosomy, described in specialized publications.     

Trisomy of 8q22.3 approximately q23-qter following an unbalanced 1;8 translocation in a boy with multiple anomalies

An 11-month-old boy was first referred with global developmental delay, pallor and heart defects (ASD, VSD, mitral and tricuspid valve insufficiency). He also had facial abnormalities. Standard karyotyping showed additional material on one chromosome 1p homolog, and fluorescence in situ hybridization (FISH) indicated an unbalanced translocation of 1pter approximately p36.33 and 8q22.3 approximately q23. The breakpoint on p was found to reside very close to the telomere, making this a rare case of "almost pure" trisomy of 8q22.3 approximately q23-qter, without a significant partial 1p36 monosomy by FISH technique. The patient's face resembled the peculiar face in previously reported cases of 8q23-qter duplication. This report supports that critical gene(s) for cardiac septum formation reside on distal chromosome 8q.     

Natural histories of patients with Wolf‐Hirschhorn syndrome derived from variable chromosomal abnormalities

Wolf‐Hirschhorn syndrome (WHS) is a subtelomeric deletion syndrome affecting the short arm of chromosome 4. The main clinical features are a typical craniofacial appearance, growth deficiency, developmental delays, and seizures. Previous genotype‐phenotype correlation analyses showed some candidate regions for each clinical finding. The WHS critical region has been narrowed into the region 2 Mb from the telomere, which includes LETM1 and WHSC1; however, this region is insufficient to cause “typical WHS facial appearance”. In this study, we identified 10 patients with a deletion involving 4p16.3. Five patients showed pure terminal deletions and three showed unbalanced translocations. The remaining patients showed an interstitial deletion and a suspected inverted‐duplication‐deletion. Among 10 patients, one patient did not show “typical WHS facial appearance” although his interstitial deletion included LETM1 and WHSC1. On the other hand, another patient exhibited “typical WHS facial appearance” although her small deletion did not include LETM1 and WHSC1. Instead, FGFRL1 was considered as the candidate for this finding. The largest deletion of 34.7 Mb was identified in a patient with the most severe phenotype of WHS.     

16q12 microdeletion syndrome in two Japanese boys

Microdeletion of 16q12 is a rare chromosomal abnormality. We present the cases of two Japanese patients with developmental and renal symptoms of differing clinical severity. Both patients had 16q12 interstitial microdeletions that included the entire SALL1 gene. Patient 1 was a 15‐year‐old Japanese boy clinically diagnosed with branchio‐oto‐renal syndrome with mild developmental delay, but with no imperforate anus or polydactyly. Array comparative genome hybridization (aCGH) indicated a 5.2 Mb deletion in 16q12, which included SALL1. Patient 2 was a 13‐year‐old Japanese boy diagnosed with Townes–Brocks syndrome and severe developmental delay, epilepsy, and renal insufficiency requiring renal replacement therapy. Fluorescence in situ hybridization indicated deletion of the entire SALL1 gene. Subsequent aCGH showed a 6 Mb deletion in 16q12q13, which included SALL1. Precise analysis of the present two cases will give us some clues to elucidate the pathogenic mechanisms of 16q12 microdeletion syndrome.     

5p部分单体3例全基因组拷贝数变异分析

目的 应用全基因组微阵列芯片平台,对染色体核型提示为Cri du chat综合征的新生儿进行全基因组拷贝数变异（CNVs）的检测,以帮助解释基因型与表型的相关性。方法 2009年6月至2010年5月复旦大学附属儿科医院收治的染色体核型提示为Cri du chat综合征的3例新生儿进入研究。采用Cytogenetic Whole Genome芯片筛查全基因组CNVs,针对发现的所有CNVs进行分析,参照国际基因组拷贝数变异多态性数据库除外正常人群多态性CNVs。结合本研究3例与DECIPHER数据库已报道的Cri du chat综合征患儿的临床表型,行5p缺失大小及范围分析,对重复区域行候选基因分析。结果 3例患儿经微阵列芯片检测,均证实并更为精确的定位了5p的缺失范围。例1 5p缺失位于5p15.33-p13.3,例2 缺失位于5p15.33-5p15.1,例3 缺失位于5p15.33-p14.3;此外例2发现9p部分重复,例3发现7p部分重复。结合DECIPHER数据库已报道的5例Cri du chat综合征临床表型,重复区域和候选基因分析显示,临床表型为猫叫样哭声或声音异常：缺失片段重叠区域为5p15.33-15.31内3.86 Mb,覆盖(IRX1和IRX2与胚胎形成相关的基因);临床表型为面容异常：缺失片段重叠区域为5p15.2-15.1内2.51 Mb（覆盖ANKH与颅骨干骺端发育相关的基因）。例3合并有先天性巨结肠。因纳入病例均为新生儿,无法评价是否存在智力低下和生长发育迟缓,无法对相应的关键区域进行分析。结论 本研究提供了微阵列平台罕见潜在致病可能CNVs的分析方法,进一步为建立5p部分缺失表型基因型关联性提供了依据。     

A further case of the recurrent 15q24 microdeletion syndrome,detected by array CGH

We report on a 10-year-old patient with developmental delay, craniofacial dysmorphism, digital and genital abnormalities. In addition, muscular hypotonia, strabism, and splenomegaly were observed; inguinal and umbilical hernias were surgically corrected. Mucopolysaccharidoses and CDG syndromes could not be found. Chromosome analysis revealed a normal male karyotype (46,XY). A more detailed investigation of the patient's genomic DNA by microarray-based comparative genomic hybridization (array CGH) detected an interstitial 3.7 Mb deletion ranging from 15q24.1 to 15q24.3 which was shown to be de novo. Interstitial deletions involving 15q24 are rare. Sharp et al. (Hum Mol Genet 16:567-572, 2007) recently characterized a recurrent 15q24 microdeletion syndrome with breakpoints in regions of segmental duplications. The de novo microdeletion described here colocalizes with the minimal deletion region of the 15q24 microdeletion syndrome. The distinct clinical phenotype associated with this novel microdeletion syndrome is similar to the phenotype of our patient with respect to specific facial features, developmental delay, microcephaly, digital abnormalities, and genital abnormalities in males. We present a genotype-phenotype correlation and comparison with patients from the literature.     

4p trisomy secondary to paternal translocation t(4p-;15q+)

A new case of trisomy 4p is reported. The patient was a boy with dysmorphism, growth failure and developmental retardation. Craniofacial features included microcephaly with a flat forehead, a prominent glabella, hyperteleorism, a broad, concave nasal bridge, a bulb-shaped nose, a wide mouth with a prominent upper lip and a short philtrum, low-set ears, a low hairline, micrognathia, and a short neck. Abdominal muscles were normal. Cryptorchidism with a hypoplastic scrotum and a micropenis were found, as well as forced flexion of the fingers and talipes equinus. The intravenous urogram disclosed ptosis of the right kidney. Developmental retardation was severe with an IQ under 50. RHG banding techniques on peripheral lymphocytes disclosed 4p14 pter duplication. The karyotype was 46,XY inv dup(4-p) (p14----pter). The mother's karyotype was normal. The father had a translocation between the short arm of chromosome 4 and the long arm of chromosome 15; his karyotype was 46,XY, t(4;15) (p14;q26). Thus, the child had trisomy for a segment of the short arm of chromosome 4 (p14----pter) and monosomy for the terminal band of the long arm of chromosome 15 (15q26). The first case of trisomy 4p was reported in 1970 by Wilson et al. Since then, there have been 46 additional reports in the medical literature. Although children with trisomy 4p share a number of features, the phenotypic manifestations of this chromosomal abnormality are variable and nonspecific, making clinical diagnosis difficult.     

11q24-q25缺失2例临床表型及文献复习

目的 应用全基因组微阵列芯片平台,对临床发现的多发性畸形患儿进行全基因组拷贝数变异（CNVs）的检测,并寻找基因型与临床表型的关系。方法 采用cytogenetic whole genome芯片筛查全基因组CNVs,针对发现的CNVs进行分析,参照国际基因组CNVs多态性数据库除外正常人群多态性CNVs。结合本研究2例与已报道的Jacobsen综合征(JBS)患儿的临床表型进行比较。结果 2例患儿SNP芯片分析为11q24-q25缺失（7.5和5.6 Mb）,均为末端的非单纯性缺失,例1存在12号染色体短臂的较大片段重复（11.5 Mb）,例2存在 11号染色体短臂的大片段重复（32.5 Mb）。2例共同缺失的部分均为JBS的关键区段,但临床表型与已报道的JBS患儿有所区别。2例均表现为头面部畸形、心血管系统异常和头颅影像学异常,均未发现血液系统异常。例1还表现为隐睾,例2表现为脾肿大。结论 对临床上难以诊断的多发性畸形可采用全基因组CNVs检测,以帮助明确诊断,对于丰富这一区段临床表型信息具有重要意义,尤其针对罕见疾病,更多的相似报道的后续出现,才能使建立表型-基因型关联性成为可能。     

Hearing impairment in a female infant with interstitial deletion of 2q24.1q24.3

Patients with interstitial deletions in 2q24.1q24.3 are rarely reported. These patients manifest a variety of clinical features in addition to intellectual disability, depending on the size and location of the deletion. We report a female patient with interstitial deletion of 5.5 Mb in 2q24.1q24.3, who showed intrauterine growth retardation, hypotonia, global developmental delay, microcephaly, and characteristic facial appearance. In addition, she had hearing impairment, with no auditory brainstem response. Case of 2q24.1q24.3 deletion with hearing impairment is quite rare. We suspect that hearing impairment is caused by bilateral cochlear nerve deficiency due to cochlear nerve canal stenosis. Further studies are necessary to evaluate hearing impairment as a clinical feature in patients with de novo heterozygous 2q24.1q24.3 deletion.     

Mosaic 7q31 deletion involving FOXP2 gene associated with language impairment

We report on a 10-year-old patient with childhood apraxia of speech (CAS) and mild dysmorphic features. Although multiple karyotypes were reported as normal, a bacterial artificial chromosome array comparative genomic hybridization revealed the presence of a de novo 14.8-Mb mosaic deletion of chromosome 7q31. The deleted region involved several genes, including FOXP2, which has been associated with CAS. Interestingly, the deletion reported here was observed in about 50% of cells, which is the first case of mosaicism in a 7q31 deletion. Despite the presence of the deletion in only 50% of cells, the phenotype of the patient was not milder than other published cases. To date, 6 cases with a deletion of 9.1-20 Mb involving the FOXP2 gene have been reported, suggesting a new contiguous gene deletion syndrome characterized mainly by CAS caused by haploinsufficiency of the genes encompassed in the 7q critical region. This report suggests that children found with a deletion involving the FOXP2 region should be evaluated for CAS and that analysis of the FOXP2 gene including array comparative genomic hybridization should be considered in selected patients with CAS. Mosaic deletions in this area may also be considered as causative of CAS.     

Severe upper airway stenosis in a boy with partial monosomy 16p13.3pter and partial trisomy 16q22qter

We report the case of a boy with a de novo partial monosomy 16p13-pter and partial trisomy 16q22-qter detected by fluorescence in situ hybridization using subtelomeric probes for 16p and 16q. The boy had facial characteristics, skeletal features, congenital heart defects, an imperforate anus, urogenital malformations, pre/postnatal growth retardation, and psychomotor retardation, most of which have been reported both in partial monosomy 16p and partial trisomy 16q. In addition, he suffered from upper airway stenosis due to possible laryngeal stenosis with subglottic webs. The upper airway stenosis could be a rare complication of partial monosomy 16p or partial trisomy 16q, or a nonspecific malformation resulting from chromosomal abnormalities.