Partial and complete trisomy 9: Delineation of a trisomy 9 syndrome

Summary Two infants with trisomy involving chromosome 9 are described. One had complete trisomy 9 and the other karyotype 47,XX,+der(9),t(7;9)(p22;q32)mat. A trisomy 9 syndrome is delineated, consisting of features of the trisomy 9p syndrome and various other malformations. These include abnormalities of the cardiovascular and urogenital systems, cranial suture anomalies, dislocation of the hips and knees and early death. A possible relationship of some of these findings to regions of 9q involved in cases of partial trisomy 9 is suggested.     

Phenotypic and cytogenetic spectrum of 9p trisomy

Trisomy 9p is one of the most frequent autosomal anomalies compatible with long survival rate. The spectrum of clinical severity in trisomy 9 roughly correlates with the extent of trisomic chromosome material. Trisomy 9p is a clinically well delineated syndrome and of all stigmata craniofacial dysmorphism is most specific. In this study we report five cases with de novo trisomy 9p. The study aimed at the identification of the genotype/phenotype correlations in patients with different breakpoints. GTG banding, DAPI stain, whole chromosome paint, centromere, telomere and 9p21 specific locus probes demonstrated that partial trisomy 9p in case 1 was due to isochromosome 9p with translocation of the long arm of re-arranged chromosome 9 onto the short arm of chromosome 13, cases 2 and 3 had intrachromosomal duplication of the short arm of chromosome 9 [dup(9)(p21p24)], case 4 had "classical" 9p trisomy and case 5 had duplication of whole short arm and part of the long arm of chromosome 9 (partial 9 trisomy). Although cases 1 to 4 had trisomy involving 9p, cases 1 and 2 exhibited the classical clinical manifestations of 9p trisomy, while cases 3 and 4 had additional features overlapping with Coffin-Siris syndrome. The present study strengthens the association of Coffin-Siris syndrome and 9p, the significance of such observations may point to possible gene location of Coffin-Siris syndrome on 9p. Case 5 had additional manifestations more than those typical of trisomy 9p which could be due to duplication of 9q21 region. Wide gap between 1st and 2nd toes, observed in the studied cases, can be added to the phenotype of this trisomy. Three of our cases had brain malformations, case 3 had dilated ventricles with hypogenesis of corpus callosum, case 4 had agenesis of corpus callosum, and case 5 had Dandy-Walker malformation. We also suggest that dosage effects of genes located in 9pter-q22 contribute to the etiology of Dandy-Walker syndrome. We recommend MRI studies as a routine in all cases with trisomy 9p.     

Prenatal diagnosis of trisomy 9.

A male karyotype with trisomy 9 (47,XY,+9) was identified in amniotic fluid cells from a 40-year-old pregnant woman. After termination of the pregnancy by saline abortion, the cytogenetic diagnosis was confirmed in a cell line grown from placental tissue. Microscopic and gross pathological findings in the fetus were compared to 1 case with trisomy 9 and 3 with trisomy 9 mosaicism reported in the literature. A distinct clinical syndrome appears to be associated with this rare autosomal trisomy.     

The dermatoglyphic and clinical features of the 9p trisomy and partial 9p monosomy syndromes

Summary The physical and dermatoglyphic features obtained from published reports of 128 patients with the trisomy 9p syndrome and 27 patients with the partial 9p monosomy syndrome are tabulated. This information is also provided on two new individuals with each of these chromosomal disorders. The dermal ridge patterns and palmar creases of trisomy 9p which are most helpful from a diagnostic standpoint are zygodactylous or absent palmar digital triradii, brachymesophalangy, reduced total finger ridge count, complex thenar/ID I patterns, transverse palmar ridge alignment, simian creases, distal axial triradii, and great toe and hallucal arch patterns. The characteristic features in partial 9p monosomy include dolichomesophalangy with accessory finger flexion creases, digital whorl patterns and elevated total finger ridge count, distal axial triradii, simian creases, and palmar dermal ridge dissociation.     

Trisomy 9p with i(9p) and t(9q18p)

Summary The trisomy 9p syndrome in a 2-year-old girl with moderate mental retardation is presented. She has a unique karyotype with a de novo isochromosome 9p and a translocation between 9q and 18p.     

Trisomy 9p resulting from maternal 9/21 translocation

Summary The clinical picture found in a child with trisomy 9p confirmed that this chromosomal syndrome is a entity, which arises from maternal translocation t(9;21).     

Tissue specific mosaicism of trisomy 9 in a patient with severe torsion scoliosis

We report on a female patient who had mosaic trisomy 9, presenting with severe scoliosis and mental retardation. Scoliosis is seldom reported in patients with mosaic trisomy 9 syndrome. FISH studies in our proband detected no trisomic cell line in the paravertebral muscle.     

Partial trisomy 17q and monosomy 9p due to a familial translocation.

Described is an infant with partial trisomy 17q and monosomy 9p [46,XX,-9,+der(9)t(9;17)(p21;q23)] due to adjacent-1 segregation of a maternal balanced reciprocal translocation. Characteristic clinical features of both partial 17q trisomy and monosomy 9p are present, but the former syndrome is less recognisable in this infant than in previously reported cases due to the concomitant 9p monosomy.     

Trisomy 9p and unusual translocation mongolism in siblings due to different 3:1 segregations of maternal translocation rcp(9;21)(p11;q11)

Summary Two sisters are described, each with a specific retardation syndrome due to a balanced reciprocal translocation 9p;21q in the mother. As a result of different 3:1 segregations, one of them has a trisomy 9p with all typical features; the other one reveals a typical Down's syndrome having an unusual translocation karyotype.     

9;21相互易位携带者生育多例9p部分三体患者细胞遗传学分析

在河南南阳收集到一个家系4代23人, 其中6人患先天性智力障碍, 具有轻度的面部和小母指畸形等特点, 先证者伴随有癫痫的发生。采用常规的外周血培养染色体G带分析, 发现先证者的核型为：46, XY, der(21) t(9; 21) (9p22.2; 21q22.3)pat, 是部分9p三体。对该家系其他成员的染色体进行分析, 发现所有患者均为部分9p三体, 异常染色体均来自9号与21号染色体平衡易位携带者染色体相互易位的异常分离, 因此这是一个部分9p三体综合征家系。而重复区段发生在9号染色体短臂远端一半区域(9pter→9p21)内, 该区是关键区, 导致智力障碍和面容轻微畸形。     

Complete trisomy 9. Two additional cases

Two infants with complete trisomy of chromosome 9 are described. One patient, died a few minutes after birth and another survived 24 hours. The main clinical findings in this syndrome are: intrauterine growth retardation, characteristic facial dysmorphism, hypoplastic external genitalia and malformations of heart, brain and skeleton.     

Trisomy 9p syndrome in two brothers: with new clinical findings and review of the literature

We report an eleven years old boy and his fourteen years old brother who both have trisomy 9p syndrome. Their cytogenetic analysis using GTL-banding showed 46,XY,der(22)add(22)(p11) karyotype. Cytogenetic analysis of their mother and sister revealed a karyogram designated as 46,XX,t(9;22) (9pter-->9p12::22p11-->22qter). With the help of FISH technique, the derivative chromosome in the proband was further confirmed to be a translocation chromosome 22 carrying the aforementioned segments from chromosome 9 which originated from a segregation event of a mother's balanced translocation. Regarding clinical aspects of our cases, both showed similar findings of 9p trisomy syndrome but low frontal hairline, circular placement of the hair around the face and scarce, inverted eyebrows, findings not previously mentioned in the literature. We conclude that these new clinical findings could be used in the clinical diagnosis of the 9p trisomy syndrome along with the other well-documented symptoms.     

The 9p- syndrome.

Six patients (4 females and 2 males) with terminal deletion of the short arm of chromosome 9 distal to band p22 are described. The disorder constitutes a clinically identifiable syndrome consisting of mental retardation, sociable personality, trigonocephaly, mongoloid eyes, wide flat nasal bridge, anteverted nostrils, long upper lip, short neck, long digits mostly secondary to long middle phalanges, and predominance of whorls on fingers. The findings suggest that the clinical features are antithetical to the trisomy 9p syndrome. The deleted chromosome segment is relatively small and could be easily overlooked. It is hoped that this delineation of clinical features seen in 9,p- patients may help in focusing attention on the small deletion.     

A satellited Yq chromosome associated with trisomy 21 and an inversion of chromosome 9

Summary A case of satellited Yq, inverted 9 and trisomy 21 is described. The clinical features are typical of those found in Down's syndrome.     

Partial trisomy 9q syndrome with a de novo tandem duplication of 9q22.2-q31.1

A female with a de novo tandem duplication of 9q22.2-q31.1 is presented. Molecular delineation of the breakpoints was made by microarray CGH and fluorescent in situ hybridisation. Involvement of 9q22.2-q31.1 seems to be sufficient to produce the characteristic phenotype of partial trisomy 9q syndrome. A discussion on the recognizable clinical features of the condition is presented.     

Partial trisomy 9 : clinical and cytogenetic correlations.

A study of three new cases with different trisomies involving chromosome 9 and a review of about 100 cases of partial trisomy 9 reported in the literature, suggested some cytogenetical and clinical correlations and lead us to propose the nomenclature of Rethore's syndrome type 1 and type 2.     

Combined trisomy 9P and Shprintzen syndrome resulting from a paternal t(9;22)

The authors report on a female infant with partial trisomy 9 (pter-->q12) together with partial monosomy 22 (pter-->q11.23) that included DiGeorge critical region (DGCR), as a result of adjacent-2 disjunction. In addition to the clinical features characteristic of trisomy 9p syndrome, the patient had Truncus arteriosus type A2, bilateral hydronephrosis, palatal anomaly, retrognathia, and laryngeal hypotonia, which are likely to be attributed to 22q11.2 deletion. This patient appears to be the first reported case with such unbalanced translocation resulting from a paternal reciprocal translocation. For live birth, the risk for male carrier is 8.7-17.4%. It is important to consider this higher risk when counseling. Precise study concerning the presence of the DGCR can facilitate in the better understanding of the condition.     

Partial trisomy 9q- chromosomal syndrome

Summary The clinical features consisting mainly of enophthalmos, beaked nose, narrow palpebral fissures, receding chin, long fingers and toes, typical for chromosomal syndrome of partial trisomy 9q, were confirmed in a new case.     

Another case of 9P-syndrome.

This paper discusses the value of an International Repository of Chromosomal Abnormalities and Variants as a means of communication and case finding. A further case of 9p- is described. The clinical and cytogenetic findings confirm the existence of a clinical entity which in many respects is the opposite of the 9p trisomy syndrome.     

Trisomy 9p in a girl whose mother has a translocation t(9;20)(q12;p13)

Summary R banding of the fine structure of the chromatids has enabled us to study a new case of trisomy for the short arm of chromosome 9. The syndrome+9p was due to nondisjunction of a maternal translocation t(9;20)(q12;p13).