Partial trisomy of the short arm of chromosome 8 resulting from balanced maternal translocation.

Extra chromosomal material on the long arm of chromosome 15 was found in an infant with growth retardation, dysmorphic features, skeletal abnormalities, and congenital heart defect. The phenotypically normal mother had a balanced translocation between the short arm of chromosome 8 and the long arm of chromosome 15: 46,XX,t(8:15)(p12:q25). Thus, the patient was partially trisomic for the short arm of chromosome 8 (p12 leads to pter). Comparison of the clinical data obtained from patients with partial trisomy of the short arm of chromosome 8 with those of full trisomy 8 (Warkany's syndrome) suggests that most of the clinical features of Warkany's syndrome require excess material from both the short and long arm of chromosome 8.     

Partial trisomy 12q associated with a familial translocation

A case is described of a female infant, who was trisomic for the terminal bands of the long arm of chromosome 12. Congenital abnormalities were present. Cytogenetic analysis on the proband's parents revealed the father to have a rare, simple translocation involving chromosomes 12 and 18.     

Partial 18q trisomy and 18p monosomy resulting from a maternal pericentric inversion,inv(18)(p11.2q21.3)

A 7-year-old boy with dysmorphic features was found to have a recombinant chromosome 18, rec(18), resulting from meiotic recombination of a maternal pericentric inversion, inv(18) (p11.2q21.3), as defined by high-resolution banding. He was trisomic for the long arm (q21.3-qter) and monosomic for the short arm (p11.2-pter) of chromosome 18. His clinical features were compared with those in other rec(18) cases, and also those in monosomy 18p, trisomy 18qter and full trisomy 18 syndromes. The risk of recombinant formation for inv(18) carriers was also discussed.     

Partial trisomy 6p and partial trisomy 22 resulting from 3:1 meiotic disjunction of maternal (6p;22q) translocation.

A male infant, partially trisomic for a small segment of chromosomes 6 and 22 resulting from a maternal translocation, is described. Comparison of the phenotypic features of the proband with those noted in partial 6p and partial 22 trisomies revealed some common features found in both chromosome anomalies but especially reinforced those features thought to be characteristic of 6p trisomy syndrome.     

Partial trisomy 16q in two boys resulting from a maternal translocation, t(15;16) (p12;q11)

Two male infants with almost complete trisomy 16q due to a maternal translocation, are reported. The phenotypic similarities of these patients who had trisomy 16q11 leads 16qter and of the eight previously published reports of partial trisomy 16q, were compared.     

Partial 18q trisomy and 18p monosomy resulting from a maternal pericentric inversion, inv(18)(p11.2q21.3).

A 7-year-old boy with dysmorphic features was found to have a recombinant chromosome 18, rec(18), resulting from meiotic recombination of a maternal pericentric inversion, inv(18) (p11.2q21.3), as defined by high-resolution banding. He was trisomic for the long arm (q21.3-qter) and monosomic for the short arm (p11.2-pter) of chromosome 18. His clinical features were compared with those in other rec(18) cases, and also those in monosomy 18p, trisomy 18qter and full trisomy 18 syndromes. The risk of recombinant formation for inv(18) carriers was also discussed.     

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 trisomy 16 as a result of familial 16;20 translocation.

Although trisomy 16 is well recognised in spontaneous abortuses, it is infrequent in livebirths and there is little information about the clinical effects. We report two sibs with partial trisomy 16q resulting in infant death. Both children were severely growth retarded with small elfin faces, prominent foreheads, low set ears, abnormal external genitalia, and intractable diarrhoea.     

Partial trisomy 6p due to maternal t(1;6) translocation

Partial trisomy 6p with duplications ranging from 6p21 to 6p25 is emerging as an established syndrome. A case of duplication of segment p22-p25 of the short arm of chromosome 6 as the result of a maternal t (1;6)(q44;p22.2) translocation in a mentally retarded girl with congenital anomalies is reported here. The associated phenotypic anomalies are compared with other reported cases of duplication 6p involving adjacent regions.     

Partial trisomy 6p from a de novo translocation (6; 18) with variable mosaicism in different tissues

Partial trisomy 6p is regarded as a distinct phenotype with short stature, failure to thrive, facial dysmorphisms with blepharophimosis, mental retardation and other malformations. An 18-month-old girl with typical features of partial trisomy 6p showed a de novo unbalanced translocation resulting in partial trisomy 6p21 to pter and partial monosomy 18p11 to pter. The translocation was observed in all fibroblasts analyzed, but only in 6% of the peripheral lymphocytes.     

Partial trisomy 7p associated with familial 7p;22q translocation.

A newly described partial trisomy of the short arm of chromosome number 7 is reported in a familial translocation between 7 and 22. The unbalanced translocation was found in one family member, the propositus, and the balanced form in 5 other members. The possibility of this translocation being a rare telomeric attachment previously undescribed in humans is discussed. Prominent clinical features include general mental and motor retardation, microbrachycephaly, and cardiac and oral abnormalities.