Partial trisomy 16p due to maternal balanced translocation.

A newborn oriental male with multiple malformations was found to have partial trisomy of 16p. The mother was found to be a translocation carrier: 46,XX,t(14;16) (q32;p12).     

Partial 18 trisomy (with 47 chromosomes) resulting from a familial maternal translocation.

A newborn female infant presented with the classical picture of 18 trisomy syndrome. Her karyotyping was 47,XX,+der(18)t(12;18)(q24;q21)mat. The mother was a balanced reciprocal translocation carrier and so too was one of the two maternal uncles of the proposita, indicating that the translocation was already present in one of the grandparents who were not available for examination. This family suggests that triplication of the distal part of the long arm of chromosome 18 is not necessary to produce Edwards' syndrome.     

Supernumerary chromosome inherited from a maternal balanced translocation leading to pure trisomy 9p

We describe a child with a supernumerary chromosome defined as der(9)t(9;22) (q12;p11), resulting in trisomy 9p and trisomy 22p. The mother carried the balanced translocation. In G- and C-banding the derivative chromosome 9 appeared to be dicentric and to contain 22q material. Using in situ hybridization we defined the exact breakpoints of the translocation and ruled out the possibility of a centric fission in the mother's chromosomes.     

Partial trisomy of the long arm of chromosome 7

A baby with partial trisomy 7, 46, XY,t (5;7) (q35;q31) resulting from a familial translocation (5q+,7q-) is reported. The clinical abnormalities of this case closely resemble those of previously reported cases of partial trisomy 7. It is suggested that partial trisomy 7 may represent a clinical entity.     

Partial trisomy 7p in two families resulting from different balanced translocations

Two families are described in which a balanced translocation producing partial trisomy 7p is segregating. Comparison is made of the phenotype produced by this aneuploidy with other cases in the literature and contrasted with that produced by partial deletion of 7p.     

Partial trisomy of the short arm of chromosome 18 due to inversion duplication and direct duplication

We report one patient with a de novo inversion duplication 18 (ptercen) and two cases of direct tandem duplication 18 (ptercen), one due to maternal inheritance and the other arising as mosaicism of unknown origin. The duplications are demonstrated by high resolution banding. They were verified by in situ hybridization with a paint specific for chromosome 18 and with DNA probe LI.84 specific for the centromere region of chromosome 18. FISH with the genomic DNA probe pHRR68 specific for 18p11.32 revealed a subtle deletion concomitantly involved in the case of inversion duplication 18p. The patients exhibit slight developmental delay/moderate mental retardation and only a few dysmorphic features. The literature on trisomy 18p is reviewed and the present cases are compared to it.     

Deletion of the proximal short arm of chromosome 8.

We report on a 5-month-old boy with a de novo interstitial deletion of the proximal short arm of chromosome 8 (p21p11.2). He manifested bilateral cleft lip and palate, and apparent hypogonadism. Four previous case reports with similar deletions (p11.1p21) were associated with hypogonadotropic hypogonadism [Beighle et al., Hum Genet 38:113-121, 1977] and hereditary spherocytosis (HS) [Chilcote et al., Blood 6:156-159, 1987; Kitatani et al., Hum Genet 78:94-95, 1988; Lux et al., Nature 345:736-739, 1990]. Our patient has no demonstrable red blood cell abnormality, suggesting that the gene for HS is located in the region 8p11.1 to 8p11.2.