Partial trisomy of 13(pter→q12) due to 47,XY,+der(13),t(13;22)(q12;q13)mat

Summary A 36-month-old boy presented with short stature, short neck, shield-shaped chest, and mental retardation. Chromosome analysis showed trisomy for the short arm and the proximal portion of the long arm of chromosome 13 [47,XY,+der(13),t(13;22)(q12;q13)mat]. The patient's mother has a balanced translocation between the long arms of chromosomes 13 and 22 [46,XX,t(13;22)(q12;q13)]. The patient's neutrophils showed an elevated number of nuclear projections and his fetal hemoglobin level was undetectable.     

Monosomy 9pter and trisomy 9q34.11qter in two sisters due to a maternal pericentric inversion

Pericentric inversions of chromosome 9 leading to unbalanced live-born offspring are relatively rare and so far only four cases have been reported. Here we present two sisters with an unbalanced recombinant chromosome 9 which resulted from a large maternal pericentric inversion inv(9)(p24.3q34.1). Further molecular characterisation of the aberrant chromosome 9 by 250k SNP array analysis showed a terminal 460 kb loss of 9p24.3 and a terminal 8.9 Mb gain of 9q34.11. We compared the clinical features of these two patients with the previous reported four cases as well as with patients with similar sized 9pter deletions or 9qter duplications. Based upon this study, we suggest that the recombinant chromosome 9 phenotype is mainly the result of duplication of a 3.4 Mb region of chromosome 9q34.11q34.13.     

Partial monosomy due to long-arm deletion of chromosome 11 : del (11) (q23) (author's transl)]

A girl, who died at 25 days of age, was found to have a partial monosomy due to a 11q23 leads to 11qter deletion. The main clinical findings were trigonocephay, facial dysmorphia, and congenital heart disease. A review of developmental and dysmorphic features of the seventeen recognized cases is presented.     

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.     

Partial monosomy 9p (9p22.2-->pter) and partial trisomy 18q (18q21.32-->qter) in a female infant with anorectal malformations

We report a female infant with a karyotype of 46,XX,der(9)t(9;18)(p22.2;q21.32)pat and the phenotypic features of craniofacial dysmorphisms, developmental delay, hypotonia, horizontal nystagmus, strabismus, congenital heart defects, clubfoot, and anorectal malformations with an anterior ectopic anus and a stenosed anal opening. Array comparative genomic hybridization revealed a 16.93-Mb deletion at 9p24.3-p22.2 encompassing the FREM1 gene and a 20.43-Mb duplication at 18q21.32-q23 encompassing the PIGN gene. We speculate that dual genome imbalances in FREMI at 9p22.3 and in PIGN at 18q21.3 are most likely responsible for the abnormal development of anorectum in this patient.     

Partial monosomy 21 (q11.2→q21.3) combined with 3p25.3→pter monosomy due to an unbalanced translocation in a patient presenting dysmorphic features and developmental delay

We describe a female patient of 1 year and 5 months-old, referred for genetic evaluation due to neuropsychomotor delay, hearing impairment and dysmorphic features. The patient presents a partial chromosome 21 monosomy (q11.2→q21.3) in combination with a chromosome 3p terminal monosomy (p25.3→pter) due to an unbalanced de novo translocation. The translocation was confirmed by fluorescence in situ hybridization (FISH) and the breakpoints were mapped with high resolution array. After the combined analyses with these techniques the final karyotype was defined as 45,XX,der(3)t(3;21)(p25.3;q21.3)dn,-21.ish der(3)t(3;21)(RP11-329A2-,RP11-439F4-,RP11-95E11-,CTB-63H24 +).arr 3p26.3p25.3(35,333-10,888,738)) × 1,21q11.2q21.3(13,354,643-27,357,765) × 1. Analysis of microsatellite DNA markers pointed to a paternal origin for the chromosome rearrangement. This is the first case described with a partial proximal monosomy 21 combined with a 3p terminal monosomy due to a de novo unbalanced translocation.     

Tertiary trisomy of 10p15.pter and 14pter.ql3 due to maternal translocation t(10;14)(p15;q13)

Double partial trisomy resulting from 3:1 segregation of the respective chromosomal segments of the chromosomes involved in a balanced translocation in meiosis is rarely reported in the literature. We present here a first patient with multiple congenital malformations associated with double partial trisomy of 10pter-p15 and 14pter-q13 resulting from 3:1 segregation of maternal balanced translocation t(10;14)(p15;q13). Proximal partial trisomy of chromosome 14 and subterminal trisomy of the short arm of the chromosome 10 are rare. The present case is the first case with double partial trisomy of these segments resulting from 3:1 segregation of a maternal balanced translocation.     

Assignment of the human phosphoserine phosphatase gene (PSP) to the pter leads to q22 region of chromosome 7

Phosphoserine phosphatase (PSP) catalyzes the hydrolysis of phosphoserine to serine. PSP expression has been examined in human-mouse somatic cell hybrids retaining different combination of human chromosomes. Human PSP is expressed only when the pter leads to q22 segment of the human 7 and its enzyme marker beta-glucuronidase (GUSB) are retained in cell hybrids. The structural gene, PSP, is therefore assigned to this region of the human 7.     

An extra idic(15p)(q11) chromosome in Prader-Willi syndrome

Using a nonfluorescent AT-specific oligopeptide antibiotic, Distamycin A, on DAPI fluorescent banding of human chromosome (DA-DAPI) as described by Schweizer et al. (1978), we have detected an additional idic(15p) chromosome in a patient with typical Prader-Willi syndrome. On the basis of the evidence available in previous studies and of our own present results, we suspect that the fundamental genetic error in the syndrome is not caused by a chromosome aberration but by a gene aberration on chromosome 15.     

Partial 4q duplication due to inherited der(20), t(4;20)(q25;q13)mat.

A boy with mental and growth retardation associated with congenital anomalies has a partial duplication of the distal 4q chromosome region as a result of inheritance of a t(4:20) from his mother. Comparison with twelve other patients from the literature indicates that similar clinical features may be associated with this chromosome change suggesting a partial 4q duplication syndrome.     

Trisomy 9p due to paternal translocation, t(9;13) (q13;q12).

A 16-year-old girl with trisomy 9p is described. She had a short stature, severe mental retardation and the following abnormal clinical findings: peculiar face with hypertelorism, downward slanting palpebral fissures, convergent strabismus, a bulbous nose with broad and prominent bridge, short upper lip, narrow, high-arched palate; short neck with low hairline; severe kyphoscoliosis and a congenital clubfoot deformity; hypoplasia and dysplasia of several phalanges of the fingers and toes and some nails, a delay by about 6 years in bone age, and remarkable dermatoglyphic patterns. The father and 3 other family members carried a balanced translocation between chromosomes 9 and 13, t(9;13)(q13;q12).     

Chorea-acanthocytosis: genetic linkage to chromosome 9q21.

Chorea-acanthocytosis (CHAC) is a rare autosomal recessive disorder characterized by progressive neurodegeneration and unusual red-cell morphology (acanthocytosis), with onset in the third to fifth decade of life. Neurological impairment with acanthocytosis (neuroacanthocytosis) also is seen in abetalipoproteinemia and X-linked McLeod syndrome. Whereas the molecular etiology of McLeod syndrome has been defined (Ho et al. 1994), that of CHAC is still unknown. In the absence of cytogenetic rearrangements, we initiated a genomewide scan for linkage in 11 families, segregating for CHAC, who are of diverse geographical origin. We report here that the disease is linked, in all families, to a 6-cM region of chromosome 9q21 that is flanked by the recombinant markers GATA89a11 and D9S1843. A maximum two-point LOD score of 7.1 (theta = .00) for D9S1867 was achieved, and the linked region has been confirmed by homozygosity-by-descent, in offspring from inbred families. These findings provide strong evidence for the involvement of a single locus for CHAC and are the first step in positional cloning of the disease gene.     

Partial duplication 14q/deletion 2q in two sibs due to t(2;14) (q37.1;q31.2) pat

Two siblings are described with duplication 14q/deletion 2q due to a paternal translocation (2;14) (q37.1;q31.2). The first one, a boy, born at term, lived 14 days. The second one, a female foetus, was born after induced labour when the anomaly was discovered by way of amniocentesis. They both had almost identical phenotypes. From a study of the literature it is inferred that a typical asymmetric head form, low set abnormal ears, micrognathia, long upper lip, rib anomalies, camptodactyly, long fingers and contractures are prominent features of the syndrome.     

An infant with trisomy 9pter yields 9q22 resulting from 3:1 segregation in a 46,XX t(1;9) (p36;q22) mother.

A newborn infant with a 47,XY,+ der(.),t(1;9) (p36;q22)mat chromosome complement and the clinical features of the 9p trisomy is described. A review of the reproductive histories of five cases with trisomy 9pter yields 9q21 or 22 indicate that the balanced translocation mothers of these infants may have as high as a 23% chance of producing a chromosomally unbalanced offspring due to 3:1 disjunction.     

Partial trisomy 14q due to familial t(14q-, 11q+) translocation

Summary A malformed male newborn with partial trisomy for the distal part of the long arm chromosome 14 (14q₂₃14qter) is described. This anomaly arose as a segregation product of a balanced t(14q-, 11q+), translocation in the father.