De novo complete trisomy 5p: Clinical and neuroradiological findings

A Thai mother and son with distal symphalangism and other associated abnormalities are reported. Distal and middle phalanges of fingers and toes 2–5 were either aplastic/hypoplastic or fused between the corresponding digits. The second fingers and fourth fingernails were most severely affected in both patients. The mother's hands were less severely affected; the middle and distal phalanges of her hands were malformed and fused. Besides the absence of fusion lines, the shape of the fused middle and distal phalanges was quite different from that of other types of fusion, i.e., fused bones in both patients did not maintain the normal configuration of bone, referring to as “middle‐distal phalangeal complex”. Distal symphalangism was observed in toes 2–5 of the mother and in toe 3 of the son. Both patients had additional clinical manifestations such as narrowing of the zygomatic arch, dental pulp stone, microdontia of a mandibular permanent central incisor, cone‐shaped epiphyses of middle phalanges of fingers, and absence of scaphoid, trapezium, trapezoid, and pisiform bones. Mutation analysis of NOG and ROR2, the genes responsible for proximal symphalangism and brachydactyly type B, respectively, was negative. © 2002 Wiley‐Liss, Inc.     

De novo trisomy 16p

We report on a patient with psychomotor retardation and a pattern of malformations comprising single umbilical artery, cranio-facial anomalies, severe truncal hypotonia, and lower-limb hyporreflexia. G-banding cytogenetics demonstrated a 16p+ chromosome. Parental chromosomes were normal. The use of fluorescent in situ hybridization (FISH) showed that this extra material derived from chromosome 16. High-resolution G-banding demonstrated a duplicated segment on the 16p arm, confirming our suspicion of a de novo tandem duplication; hence, the cytogenetic diagnosis was given as 46,XY,dir dup(16)(p11.2→p12). Am. J. Med. Genet. 68:219–221, 1997 © 1997 Wiley-Liss, Inc.     

De novo trisomy 20p of paternal origin

We report on a case of a de novo trisomy 20p in a 5-year-old boy. The patient presented with dysmorphic features, mental retardation, poor coordination, cardiac malformation, kyphosis, hypospadias, cryptorchidism, and preaxial hexadactyly. No growth delay was noticed. Standard karyotype and FISH techniques allowed the characterization of the chromosome rearrangement showing a duplication spanning almost the whole short arm of chromosome 20. Therefore the karyotype was interpreted as 46,XY,der(20)(pter --> q13.3::p11.2 --> pter). Molecular studies identified the duplication of paternal origin. This is one of the rare reports with almost pure trisomy 20p characterized at the molecular level. Its phenotype is compared to other similar cases described in the literature.     

De novo trisomy 16p11.2-qter: report of an infant

We report on a four-month-old girl with a de novo trisomy 16q [47,XX, +del(16)(p11.2).ish del(16)(p11.2)(wcp16+,D16Z2+,tel16q+, tel16p-)]. She had minor facial anomalies, limb anomalies, urogenital abnormalities, and severe cardiovascular defects. Autopsy confirmed left hypoplastic lung, total anomalous pulmonary venous drainage via coronary sinus, persistent left superior vena cava, patent ductus arteriosus, secundum atrial septal defect, bilateral hydronephrosis and hydroureters, uterus bicornis, and ovarian hypoplasia. Short tandem repeat polymorphism analysis indicated that the additional, structurally abnormal chromosome 16 was maternal in origin.     

De novo trisomy 16p11.2‐qter: Report of an infant

We report on a four‐month‐old girl with a de novo trisomy 16q [47,XX,+del(16)(p11.2).ish del(16)(p11.2)(wcp16+,D16Z2+,tel16q+, tel16p−)]. She had minor facial anomalies, limb anomalies, urogenital abnormalities, and severe cardiovascular defects. Autopsy confirmed left hypoplastic lung, total anomalous pulmonary venous drainage via coronary sinus, persistent left superior vena cava, patent ductus arteriosus, secundum atrial septal defect, bilateral hydronephrosis and hydroureters, uterus bicornis, and ovarian hypoplasia. Short tandem repeat polymorphism analysis indicated that the additional, structurally abnormal chromosome 16 was maternal in origin. Am. J. Med. Genet. 92:308–310, 2000. © 2000 Wiley‐Liss, Inc.     

De novo partial trisomy 15q (proximal type).

This report describes a retarded girl with strabismus, high arched palate, antimongoloid slant, low set ears, hearing loss, micrognathia, short neck, and an anteriorly displaced anus. She was found to have a de novo partial trisomy of the proximal part of the long arm of chromosome 15.     

De novo 16p deletion: ATR-16 syndrome

We describe a child with α-thalassemia ascertained by newborn screening. Evaluation at 9 months of age showed minor anomalies and developmental delay. Chromosomal analysis demonstrated a de novo deletion of the most distal portion of the short arm of chromosome 16, which contains the α-globin genes. Analysis of the α-globin locus by Southern blot analysis did not demonstrate altered band sizes at this locus; however, analysis of the films using densitometry confirmed hemizygosity. This is the fifth reported case of the ATR-16 syndrome (α-thalassemia retardation-16) not complicated by duplication or deletion of other chromosomes. Am. J. Med. Genet. 72:451–454, 1997. © 1997 Wiley-Liss, Inc.     

A new case of "complete" trisomy 5p with isochromosome 5p associated with a de novo translocation t(5;8)(q11;p23)

A boy with a de novo translocation t(5;8)(q11;p23) and an isochromosome 5p is described. The main clinical features found in the complete trisomies 5p are reviewed and the mechanisms of the chromosomal rearrangements involving centromeric and telomeric regions are discussed.     

De novo 5q35.5 duplication with clinical presentation of Sotos syndrome

We report on a girl with developmental delay and a de novo 264 kb interstitial duplication in the region of Sotos syndrome at 5q35.3 in the immediate vicinity of critical NSD1 gene, but manifesting the phenotype, of overgrowth both prenatal stage and postnatal, macrocephaly, developmental delay, and resembling that of Sotos syndrome, rather than the recently reported syndrome of reciprocal duplication. The duplication is located right downstream from the NSD1 gene, a region which appears critical for the expression of the gene as regulatory elements might be disrupted or the expression of a not amplified critical gene might be otherwise affected by the duplicated region. Thus,in the process of evaluating identified CNVs attention should be drawn to the possible influence of chromosomal rearrangement on distant genes, which could add additional diversity to genomic disorders. Our case demonstrates that evaluation of the size of chromosomal alteration and gene content are not sufficient for assessment of CNV's pathogenicity and the context of adjacent genes should be considered.     

A case of de novo trisomy 12p syndrome

A case of pure 12p trisomy was discovered in a 14-year-old boy during a cytogenetic survey of Egyptian students attending a school for mentally retarded children. The patient had a normal birth weight but later showed developmental delay. Clinical examination at 14 years of age revealed a high bulging forehead, broad and flat nasal bridge, large mouth with everted lower lip, folded upper ear helix with protuberant antihelix, pectus excavatum, undescended testes, flat feet, generalized hypotonia and moderate mental retardation. Chromosomes analyzed from blood lymphocytes showed an enlarged short arm with an additional band on one of the no. 12 chromosomes. The duplicated chromosomal material extended from 12pter----p12.2, including the LDH-B locus, which showed a gene-dosage effect. This extra chromosomal material arose de novo by tandem duplication. The parents' chromosomes were normal.     

Proximal 5p trisomy resulting from a marker chromosome implicates band 5p13 in 5p trisomy syndrome

We describe an infant with trisomy of (5)(p10p13.1) resulting from a de novo marker chromosome. The marker's origin was identified by chromosome microdissection and reverse in situ hybridization. The clinical findings are compared to those of other partial and complete 5p duplications. This case further defines the critical region of 5p trisomy syndrome to proximal 5p. Am. J. Med. Genet. 87: 6–11, 1999. © 1999 Wiley-Liss, Inc.     

De novo deletion (2) (p11.2p13): clinical, cytogenetic, and immunological data.

We report a case of a boy with a de novo interstitial deletion of chromosome (2) (p11.2p13). Clinical features included dysmorphism of the face, genital region, and limbs, psychomotor retardation, and vitiligo. A reduced ratio of immunoglobulin (Ig) light chain expression (kappa/lambda ratio: 0.7) was found, compatible with deletion of one Ig kappa allele on chromosome 2p12. The patient had no clinical or laboratory signs of immunodeficiency.     

De novo partial duplication of 17p [dup(17)(p12----p11.2)]: clinical report

Duplication of band p11.2 and a small proximal portion of band p12 of chromosome 17 was noted in an infant with unusual facial appearance and left calcaneovalgus deformity. Developmental delay was documented over time. Only one other similar case has been found in the literature, but deletion of the same region is known in nine recently described cases [Smith et al, 1986]. This suggests that abnormalities of this small region of 17p are relatively common and only recently detectable with modern high-resolution techniques.     

De novo tandem duplication 17p11→cen

A dicentric chromosome 17 is described in a 5-year-old girl with minor malformations and severe mental retardation. The anomaly is interpreted as a de novo duplication of band 17p11 and centromere 17.