Trisomy of the short arm of chromosome 4: the changing phenotype with age.

In this paper the authors describe three patients with trisomy of the short arm of chromosome 4 with special attention to the striking phenotypic changes with age. When they get older the round face with chubby cheeks, deeply-set eyes and broad and flat nasal root with a bulbous nose tip becomes triangular or even long. Postnatal growth retardation is pronounced with short neck and broad, short chest with hyperkyphosis. The moderate to severe mental retardation is associated with almost absence of speech development, severe behavioural problems and poor fine motor development with persisting hypertonia, stiff, unstable gait, joint contractures and seizures.     

Trisomy of chromosome No. 10 in mosaic (author's transl)

A case of trisomy of chromosome No. 10 in mosaic is described in a boy who died at the age of 6 months. The frequency of pathological cells is less than 30% (28% from lymphocytes, 20% from fibroblasts); it is possible, anyway, to rule out the hypothesis of a cellular cloning in vitro, since the trisomy 10 was observed in two different cultures, terminated after 48 and 72 hours. The parents' karyotype was normal, except for a litte number (6%) of cells with trisomy 10 from cultured lymphocytes of the mother. The morphological features of the present case are compared with those of the boy described by Higurashi et al. in 1969 (mosaic of trisomy 10, with a higher frequency of pathological cells).     

Presumed trisomy for the short arm of chromosome No. 9 not due to inherited translocation

Summary 4 patients trisomic for the short arm of a chromosome No. 9 due to segregation of paternal translocations were described recently by Rethoré and associates. In this context, we report on a retarded child, in whom the examination of lymphocyte and fibroblast metaphases revealed the existence of an additional small acrocentric marker chromosome. Cytogenetic data do not exclude the possibility of the marker to be derived from a chromosome No. 9 which exhibits, in the father, a more conspicuous secondary constriction than usual. A breakage event at this site and subsequent non-disjunction of the centric fragment (i.e. chromosome 9 short arm) during paternal gametogenesis could have given rise to the child's chromosomal constitution.This assumption is supported by the presence of clinical features in the patient held to be characteristic for the 9p trisomy phenotype by Rethoréet al.: facial dysmorphia with mild hypertelorism and deep set eyes, a globulous nose and an abnormal anthelix. In addition, the severely retarded patients exhibit to a variant degree hypoplasia of phalanges, abnormalities of finger creases and disturbances of palmar ridge patterns, all of which were not typically expressed in our patient.

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Zusammenfassung Rethoré u. Mitarb. beschrieben kürzlich 4 Patienten, bei denen auf Grund familiärer Translokations-Heterozygotie jeweils eine Trisomie für den kurzen Arm eines Chromosoms 9 angenommen werden kann. In diesem Zusammenhang berichten wir über ein retardiertes Kind, das in Lymphocyten und Fibroblasten ein zusätzliches kleines akrozentrisches Chromosom aufweist. Die cytogenetische Analyse, darunter die Beobachtung einer prominenten constriktion an einem Chromosom Nr. 9 beim Vater des Patienten, lassen die Herkunft des kindlichen Markers von dem kurzen Arm dieses Chromosoms möglich erscheinen: ein hypothetisches Bruchereignis im Bereich der Constriktion und nachfolgende meiotische Non-Disjunktion werden diskutiert.Die Annahme einer Trisomie für den kurzen Arm eines Chromosoms 9 wird bei dem hier vorgestellten Patienten unterstützt durch das Vorhandensein von Merkmalen, die nach Rethoré u. Mitarb. für das Trisomie 9p-Syndrom sprechen. Im Kopfbereich sind das vor allem: kleine Orbita, angedeuteter Hypertelorismus, ballenartige Nasenkuppe sowie auffällige Anthelixkonfiguration. Im Extremitätenbereich zeigen die erheblich geistig retardierten Patienten in variablem Ausmaß eine Hypoplasie der Phalangen sowie abnorme Beugefalten und reduktion oder Fehlen der palmaren Triradii.

     

Trisomy for distal segments of the long arm of chromosome 1

Clinical genetic analysis of distal trisomies 1q, based on the study of a t(1; 6) (q42.1; p24) family and the literature data, was performed. It was demonstrated that phenotypical manifestations of the trisomy are formed by nonspecific anomalies, due to imbalance as such, and by rather specific anomalies caused by triplication of a "critical segment". 1q42-1qter appeared to be such a segment for distal trisomy 1q.     

The gene encoding human vimentin is located on the short arm of chromosome 10.

The gene for vimentin, an intermediate-filament protein, is growth regulated. We used Southern blot analysis and in situ chromosome hybridization to determine the location of the human vimentin gene. Our results show that there is only one copy of the vimentin gene and that it is located on the short arm of chromosome 10 (10pter-10q23) close to the interleukin-2 receptor gene, which is also growth regulated. In situ hybridization studies suggest that the most likely location of the vimentin gene is 10p13. Sequence similarities and homologies of human vimentin to other genes are presented.     

Mewing cry in a child with the partial deletion of the short arm of chromosome No. 4

Summary A case is presented of partial deletion of the short arm of the chromosome No. 4, but with a mewing cry, typical of the 5p — deletion syndrome. The clinical examination revealed similar features to those described in other cases of 4p — deletion, namely low birth weight, hypertelorism, facial asymmetry, failure to thrive, mental retardation, beak-shaped nose, low set ears, broad nasal bridge, skeletal anomalies and hypotony. The mewing character of the voice was confirmed by analysis of the voice spectrum. The deleted chromosome was identified by the measurement technique.     

Familial paracentric inversion of the short arm of chromosome 3.

A paracentric inversion of the short arm of chromosome number 3 is reported in three generations of a family. The index patient presented with slight psychomotor retardation. The literature on this subject is briefly reviewed.     

Mapping the short arm of human chromosome 16

Physical mapping of 13 different breakpoints on the short arm of chromosome 16 using previously mapped probes and the subsequent mapping of additional probes enabled the division of this portion of the chromosome into six different intervals. D16S94 was mapped between HBA and D16S80 and is closer to PKD1 than either HBA or D16S80. A tight linkage group which includes FRA16A, D16S8, and D16S79 was identified. Seven breakpoints, including FRA16A, could not be separated by probe localizations. This study provides the basis for the development of detailed maps of the short arm of chromosome 16.     

Reciprocal translocation between Y chromosome long arm euchromatin and the short arm of chromosome 1

A case with an apparently balanced reciprocal translocation between the long arm of the Y chromosome and the short arm of chromosome 1 t(Y;1)(q11.2;p34.3) is described. The translocation was found in a phenotypically normal male ascertained by infertility and presenting for intra-cytoplasmatic sperm injection treatment. Histological examination of testicular biopsies revealed spermatogenic failure. Chromosome painting with probes for chromosome 1 and for the euchromatic part of the Y chromsome confirmed the translocation of euchromatic Y chromosomal material onto the short arm of chromosome 1 and of a substantial part of the short arm of chromosome 1 onto the Y chromosome. Among the Y/autosome translocations, the rearrangements involving long arm euchromatin of the Y chromosome are relatively rare and mostly associated with infertility. Microdeletion screening at the azoospermia locus revealed no deletions, suggesting another mechanism causing infertility in this translocation carrier.     

Partial deletion of the long arm of chromosome No. 13

Summary A case of partial deletion of chromosome No. 13 identified by G banding as 46,XX,del(13)(q21-qter) is reported in an infant with severe microcephaly, microphthalmos, talipes calcaneovalgus, and a single crease on each of the little fingers. A review of other cases of chromosome No. 13 deletion that were identified by banding is presented and the correlation between clinical features and deletion of specific bands is discussed.