Interstitial deletion 13q. Further delineation of the syndrome by clinical and high-resolution chromosome analysis of five patients

Five patients with interstitial deletion 13q are reported. High-resolution chromosome banding established the diagnosis in two cases and stated the exact breakpoints in three remaining cases. All parents had normal chromosomes. An unequal and so far unexplained sex ratio of previously published and present cases was found: M:F = 1:2.75. Moderate to severe growth retardation was prominent in all patients. The patients were followed with psychological tests and growth data for 3–10 years. Mild to moderate mental retardation was present. Considerable phenotypic similarities were found in two patients with del(13)(q21.33 q31.3) and one with del(13)(q14.3q22.3). Repeat ophthalmological examinations showed no evidence of retinoblastoma in a male with del(13)(ql3.1q21.1). In conclusion, the long-term study of five patients with interstitial deletion 13q, all evaluated with high-resolution banding, contributed to a more reliable mental and growth prognosis in such patients.     

Small interstitial deletion of the long arm of chromosome 2 (2q24.3): Further delineation of 2q medial monosomy syndrome

Summary We report on a female infant with an interstitial deletion involving 2q24.3. She had multiple congenital anomalies similar to those in patients with del(2)(q31q33) except for an occipital encephalocele. As a result of comparison of clinical findings among interstitial 2q deletions, a distinct 2q medial monosomy syndrome may be delineable in association with a deletion of 2q31.     

Further delineation of the dup(3q) syndrome

Three patients with duplication of 3q regions ranging from 3q25----qter to the entire long arm provide additional documentation of the dup(3q) malformation syndrome. Data on 40 cases now reported define a characteristic face with hirsutism, synophrys, broad nasal root, anteverted nares, downturned corners of the mouth, micrognathia, and malformed ears recognizable even in the 30-week fetus and distinct from that of the Brachmann-de Lange syndrome. Other characteristic anomalies include congenital heart anomalies involving primarily septal defects, hand malformations including simian creases, abnormal dermatoglyphics, clinodactyly or camptodactyly, omphalocele, skeletal anomalies, and genitourinary malformations. Severe mental and growth retardation are common in those patients (64%) who survive the first year. Chromosome study of relatives is extremely important for counseling because only 10 of 40 cases represented de novo duplications.     

Patient with terminal duplication 3q and terminal deletion 5q: comparison with the 3q duplication syndrome and distal 5q deletion syndrome

Partial duplication of chromosome 3q is a well-described condition of multiple congenital anomalies and developmental delay that resembles the Brachmann-de Lange syndrome. Similarly, an emerging phenotype of a distal 5q deletion syndrome has recently been described. The combination of both chromosome abnormalities has not been previously described. We report on a child with both a de novo duplication of distal 3q (q27 --> qter) and terminal deletion of 5q (q35.2 --> qter). The patient had facial anomalies, hypoplastic toenails, lymphedema of the dorsum of the feet, type I Chiari malformation, a seizure disorder, and moderate developmental delays. The phenotype is compared and contrasted to the few reports of patients with similar terminal 3q duplications and 5q deletions. Our patient did not have the characteristic phenotype of the 3q duplication syndrome, suggesting that the chromosome region responsible for this phenotype is more proximal than the terminal 3q27 region. In addition, comparison with three other reported cases of terminal 5q35 deletions suggests a possible association of terminal 5q deletions with central nervous system (CNS) structural abnormalities.     

Cytogenetic molecular delineation of a terminal 18q deletion suggesting neo-telomere formation

Deletion of the long arm of chromosome 18 is one of the most common segmental aneusomies compatible with life and usually involves a deletion of the terminal chromosomal region. However, the mechanisms implicated in the stabilization of terminal deletions are not well understood. In this study, we analyzed a girl with moderate mental retardation who had a cytogenetically visible terminal 18q deletion. In order to characterize the breakpoint in the terminal 18q region, we used fluorescence In situ hybridization (FISH) with bacterial artificial chromosomes (BACs) and pan-telomeric probes and also the array technique based on comparative genomic hybridization (array-CGH). FISH with pan-telomeric probes revealed no signal in the terminal region of the deleted chromosome, indicating the absence of normal telomere repeat (TTAGGG)n sequences in 18q. We suggest that neo-telomere formation by chromosome healing was involved in the repair and stabilization of this terminal deletion.     

The chromosome 9q subtelomere deletion syndrome

The chromosome 9q subtelomere deletion syndrome (9qSTDS) is among the first and most common clinically recognizable syndromes to arise from widespread testing by fluorescent in situ hybridization (FISH) of subtelomere deletions. There are about 50 reported cases worldwide. Affected individuals invariably have severe hypotonia with speech and gross motor delay. The facial gestalt is distinct and features absolute or relative micro- or brachycephaly, hypertelorism, synophrys, and/or arched eyebrows, mid-face hypoplasia, a short nose with upturned nares, a protruding tongue with everted lower lip and down-turned corners of the mouth. Approximately half of affected individuals have congenital heart defects (primarily ASD or VSD). A significant minority have epilepsy and/or behavioral and sleep disturbances. A variety of other major and minor eye, ear, genital, and limb anomalies have been reported. Most patients have sub-microscopic deletions of the subtelomere region of chromosome 9q34.3 that range from <400 kb to >3 Mb. The 9qSTDS is caused by haplo-insufficiency of EHMT1, a gene whose protein product (Eu-HMTase1) is a histone H3 Lys 9 (H3-K9) methyltransferase. This was established by identification of three patients with features of the syndrome and either mutations or a balanced translocation in EHMT1. H3-K9 histone methylation is restricted to the euchromatin of mammals and functions to silence individual genes. Deletion size does not correlate with the severity of the 9qSTDS since patients with mutations in EHMT1 are as severely affected as those with submicroscopic deletions. Patients clinically suspected of having the 9qSTDS but with normal subtelomere deletion testing by FISH or MLPA should be considered for detailed 9q MLPA analysis and/or sequencing of EHMT1. EHMT1 is another example in the growing list of genes responsible for brain development that appear to play a role in chromatin remodeling. Published 2007 Wiley-Liss, Inc.     

Partial deletion of chromosome 6p: delineation of the syndrome

Here we summarize the clinical findings of five new patients and nine patients reported in the literature with deletions of the short arm of chromosome 6. The del(6p) syndrome appears to include the following clinical findings: mental retardation, microcephaly, abnormal sutures, broad nasal bridge, various eye and ear abnormalities, a short neck with excess skin folds, and a normal birth weight and length.     

A child with multiple congenital anomalies and karyotype 46,XY,del(14)(q31q32.3): further delineation of chromosome 14 interstitial deletion syndrome

We report on an infant with a multiple congenital anomaly syndrome and severe developmental delay in association with a previously undescribed de novo interstitial deletion of chromosome 14 [karyotype: 46,XY,del(14) (q31q32.3)]. Comparison of the presented patient with previously reported cases of interstitial and terminal chromosome 14q deletions provides a group of patients monosomic for various overlapping portions of the distal half of chromosome 14q and suggests a limited similarity in phenotype among patients with common deleted 14q segments. All patients with distal 14q deletions were developmentally delayed, most were microcephalic and failed to thrive. Most of the patient's anomalies were limited to the face and head. Few major internal congenital anomalies were observed. These comparisons serve to further clarify possible associations of subchromosomal aberrations with specific phenotypes.     

Further delineation of the partial proximal trisomy 10q syndrome.

We report on a girl with a partial duplication of the proximal part of the long arm of chromosome 10, confirmed by chromosome painting. The phenotypic findings are compared to those found in six other published cases with the same karyotype. Recognition of a specific partial proximal trisomy 10q syndrome seems to be possible, consisting of mild to moderate developmental delay, postnatal growth retardation, microcephaly, prominent forehead, small and deep set eyes, epicanthus, upturned nose, bow shaped mouth, micrognathia, thick and flat helices of the ears, and long, slender limbs. Severe ocular malformations are possibly part of the syndrome. No major phenotypic differences were seen between patients with a duplication of segment 10q11-->10q22 and patients with a duplication of 10q21-->10q22.     

Interstitial deletion 13q: further delineation of the syndrome by clinical and high-resolution chromosome analysis of five patients

Five patients with interstitial deletion 13q are reported. High-resolution chromosome banding established the diagnosis in two cases and stated the exact breakpoints in three remaining cases. All parents had normal chromosomes. An unequal and so far unexplained sex ratio of previously published and present cases was found: M:F = 1:2.75. Moderate to severe growth retardation was prominent in all patients. The patients were followed with psychological tests and growth data for 3-10 years. Mild to moderate mental retardation was present. Considerable phenotypic similarities were found in two patients with del(13)(q21.33 q31.3) and one with del(13)(q14.3q22.3). Repeat ophthalmological examinations showed no evidence of retinoblastoma in a male with del(13)(q13.1q21.1). In conclusion, the long-term study of five patients with interstitial deletion 13q, all evaluated with high-resolution banding, contributed to a more reliable mental and growth prognosis in such patients.     

Delineation of 14q32.3 deletion syndrome.

A patient with a 14q32.3 terminal band deletion and cat cry is reported. Review of four other 14q32.3 deletion cases suggests the possible presence of a recognisable 14q32.3 terminal deletion syndrome, which is characterised by (1) apparently postnatal onset of small head size in comparison to body size, (2) high forehead with lateral hypertrichosis, (3) epicanthic folds, (4) broad nasal bridge, (5) high arched palate, (6) single palmar crease, and (7) mild to moderate developmental delay. Although none of the above seven features in unique to this syndrome, and indeed are quite common in other chromosomal disorders or genetic syndromes, patients with a terminal 14q32.3 deletion do show a recognisable facial gestalt. Interestingly, unlike ring chromosome 14, the 14q32.3 terminal deletion has rarely been reported, possibly because it is harder to detect, and an optimal chromosome preparation is required for its identification.     

Sclerocornea associated with the chromosome 22q11.2 deletion syndrome

Reported ocular findings in the 22q11.2 deletion syndrome (which encompasses the phenotypes of DiGeorge, velocardiofacial, and Takao (conotruncal-anomaly-face) syndromes) have included posterior embryotoxon (prominent, anteriorly displaced Schwalbe's line at the corneal limbus or edge), retinal vascular tortuosity, eyelid hooding, strabismus, and astigmatism. We present seven 22q11.2 patients from multiple centers with sclerocornea, an eye finding previously unreported in the literature. Four boys and three girls were identified with sclerocornea, systemic DGS/VCFS findings, and fluorescence in situ hybridization (FISH)-confirmed microdeletion at chromosome 22q11.2. FISH diagnosis was perinatal in six patients but at 2 years of age in one child. Sclerocornea was bilateral in five patients. Findings included descemetocele (five eyes), microophthalmos (one eye), iridocorneal adhesions (one bilateral case), and severe anterior segment dysgenesis (one eye). Two patients underwent bilateral corneal transplantation; another two were scheduled for possible unilateral transplant. Sclerocornea is a static congenital condition in which the cornea is opaque and vascularized and resembles the sclera. The novel finding of sclerocornea suggests that a genetic locus at 22q11.2 may be involved in anterior segment embryogenesis. In most of our patients, the diagnostic process was underway, but in one patient 22q11.2 deletion was not suspected until after the child had already been undergoing treatment for sclerocornea for 2 years. Sclerocornea should be added to the clinical manifestations of the 22q11.2 deletion syndrome. Ophthalmologists diagnosing sclerocornea in children with systemic findings suggestive of 22q11.2 deletion should ensure appropriate genetic referral.     

Association of terminal chromosome 1 deletion with Sertoli cell-only syndrome

We report on del(1)(q44), developmental delay, cryptorchidism, and seizure disorder in a 19-year-old man. Endocrinologic evaluation showed delayed puberty and elevated gonadotropins. Testicular biopsy was consistent with Sertoli cell-only syndrome. The case illustrates a previously an unreported manifestation in males with del(1)(q44), and suggests a link between the development of germinal epithelium and genes in the 1q44 area. Am. J. Med. Genet. 80:396–398, 1998. © 1998 Wiley-Liss, Inc.     

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.     

Further delineation of the acro-renal-ocular syndrome

A triad of acral, renal, and ocular abnormalities was reported previously in four families. We report on a fifth family, in which a mother, one of her four sons and one of her two daughters are affected. Major findings in the acro-renal-ocular syndrome are upper limb abnormalities, mainly thumb hypoplasia, eye abnormalities such as coloboma and Duane anomaly and renal migration defects. A close embryological-temporal relationship between the traits of this entity suggest a common monogenic cause. The pattern of inheritance is probably autosomal dominant. Because of a wide variability of clinical manifestations, recognition of the syndrome in individual cases may be difficult. © 1996 Wiley-Liss, Inc.