Small terminal deletions of the long arm of chromosome 2: Two new cases

We report on 2 girls with small de novo terminal deletions of the long arm of chromosome 2 and breakpoints within q37. Four cases with similar or more extensive deletions have been previously reported in full. Hypotonia and psychomotor retardation were the only manifestations common to all 6 cases. The phenotype associated with small terminal 2q deletions is variable and clearly not always as mild as indicated in previous reports. The abnormality may also be more common than has been assumed. © 1994 Wiley-Liss, Inc.     

Interstitial deletion of the distal long arm of chromosome 4.

We report the first case of an interstitial deletion of the distal long arm of chromosome 4 (q31.22----q34.2). The major clinical features are described and compared to those of other published reports of del 4q, mainly those sharing a common deleted segment with the present case (both interstitial and terminal). This comparison suggests that the characteristic phenotype attributed to terminal deletions of 4q31----qter probably mainly results from loss of the segment q31----q33-34.     

Interstitial deletion of the long arm of chromosome 11.

A girl with an interstitial deletion of the long arm of chromosome 11 is described. The patient was mildly mentally retarded and showed some facial dysmorphic features, including hypertelorism, ptosis, and cleft palate.     

Distal long arm deletions of the X chromosome and ovarian failure

A mother and daughter are described with premature menopause and deletion of the X chromosome at q28.     

Two Burkitt's lymphomas with chromosome 6 long arm deletions

Two new European Burkitt's lymphoma (BL) cases are reported. Their karyotypic abnormalities were unusual, without involvement of chromosomes #8, #14, #2, or #22. However, in both tumors, a 6q- chromosome was, present. These findings raise questions about the definition of BL and the involvement of various different DNA sequences in the mechanisms of BL genesis.     

Sex chromosome mosaicism in males carrying Y chromosome long arm deletions

Microdeletions of the long arm of the Y chromosome (Yq) are a common cause of male infertility. Since large structural rearrangements of the Y chromosome are commonly associated with a 45,XO/46,XY chromosomal mosaicism, we studied whether submicroscopic Yq deletions could also be associated with the development of 45,XO cell lines. We studied blood samples from 14 infertile men carrying a Yq microdeletion as revealed by polymerase chain reaction (PCR). Patients were divided into two groups: group 1 (n = 6), in which karyotype analysis demonstrated a 45,X/46,XY mosaicism, and group 2 (n = 8) with apparently a normal 46,XY karyotype. 45,XO cells were identified by fluorescence in-situ hybridization (FISH) using X and Y centromeric probes. Lymphocytes from 11 fertile men were studied as controls. In addition, sperm cells were studied in three oligozoospermic patients in group 2. Our results showed that large and submicroscopic Yq deletions were associated with significantly increased percentages of 45,XO cells in lymphocytes and of sperm cells nullisomic for gonosomes, especially for the Y chromosome. Moreover, two isodicentric Y chromosomes, classified as normal by cytogenetic methods, were detected. Therefore, Yq microdeletions may be associated with Y chromosomal instability leading to the formation of 45,XO cell lines.     

Wisconsin syndrome in a patient with interstitial deletion of the long arm of chromosome 3: further delineation of the phenotype

Interstitial deletions of the long arm of chromosome 3 are uncommon. Most cases are related to the blepharophimosis-ptosis-epicanthus inversus syndrome (BPES), which is mapped to 3q23. We report on a case with a de novo chromosomal deletion of 3q23 and 3q25. We review the literature on the reported cases of 3q deletion and find that the condition of our patient is not typical of the BPES. Rather, she shares similarity to a patient with Wisconsin syndrome, first discovered in 1976.     

Terminal deletions of the long arm of chromosome 7: five new cases

Twenty-two cases of terminal deletions of the long arm of chromosome 7 have been reported. We present 5 new cases, 3 of which were ascertained due to fetal holoprosencephaly, one due to anencephaly, and one due to multiple structural defects in a 15-year-old boy. The presence of holoprosencephaly in 3 of the 5 cases reported herein and in 2 previously reported cases suggests that this manifestation may be commonly observed in individuals with deletion 7q.     

Interstitial deletion in the long arm of chromosome no. 5

A case of a male infant with several congenital anomalies combined with an interstitial deletion of the long arm of chromosome no. 5 is presented. The symptoms of the infant were compared to five previous reported cases with similar interstitial deletions in 5q.     

Tetrasomy of the short arm of chromosome 9: prenatal diagnosis and further delineation of the phenotype

A fetus with multiple malformations was identified by prenatal ultrasound investigation. Cordocentesis and fetal lymphocyte chromosome analysis demonstrated a model number of 47 chromosomes. The extra chromosome material was identified as an isochromosome of the entire short arm of chromosome 9 with no involvement of the heterochromatic region of the long arm [47,XY, + i(9p)]. This represents the first report of prenatal diagnosis of tetrasomy 9p. Further delineation of the phenotype is discussed.     

Hematologic manifestations associated with deletions of the long arm of chromosome 20

We investigated 20 patients with hematologic disorders who had a clone of cells with a deletion of most of a chromosome #20 long arm (20q?) in the bone marrow. Three patients had polycythemia vera (PV), 6 had acute nonlymphocytic leukemia (ANLL), 8 had preleukemia (PL), and 3 had other myeloproliferative disorders. In our laboratory, a 20q? chromosome is found in 6% of patients with PV, 3% of patients with ANLL, and 1% of patients with PL. Among the 6 patients with ANLL and a 20q? abnormality, 3 had erythroleukemia. There were no apparent clinical differences among our patients with 20q? chromosomes compared with other patients with similar disorders who did not have a 20q? chromosome. The breakpoint of the 20q? anomaly, in each instance, was in band 20q11, but it occurred near the centromere at 20q1101 in 16 patients and at the distal part of this band at 20q1109 in 4 patients. Three of the 4 patients with a breakpoint at 20q1109 had PL.     

Interstitial deletion of the short arm of chromosome 4.

A 17 year old girl investigated for mental retardation and minor anomalies was found to have an interstitial deletion of 4p. Her clinical and cytogenetic findings are compared with previous reported case of interstitial 4p deletion and with terminal 4p--deletions (Wolf-Hirschhorn syndrome).     

Two cases with different deletions of the long arm of chromosome 7.

Two mentally and physically retarded girls, one with an interstitial deletion 7 (pter leads to q21::q32 leads to qter), and the other with an interstitial deletion 7 (pter leads to q11::q22 leads to qter), are described. Their clinical features are compared with those of 11 earlier reported cases with a deletion 7q. The Hageman factor, the locus of which is assigned to the distal part of 7q, was in both cases within normal limits. The data available do not justify the delineation of a specific clinical syndrome.     

Interstitial deletion 13q: further delineation of the syndrome by clinical and high-resolution chromosome analysis of five patients

Five patients with interstitial deletion 13q are reported. High-resolution chromosome banding established the diagnosis in two cases and stated the exact breakpoints in three remaining cases. All parents had normal chromosomes. An unequal and so far unexplained sex ratio of previously published and present cases was found: M:F = 1:2.75. Moderate to severe growth retardation was prominent in all patients. The patients were followed with psychological tests and growth data for 3-10 years. Mild to moderate mental retardation was present. Considerable phenotypic similarities were found in two patients with del(13)(q21.33 q31.3) and one with del(13)(q14.3q22.3). Repeat ophthalmological examinations showed no evidence of retinoblastoma in a male with del(13)(q13.1q21.1). In conclusion, the long-term study of five patients with interstitial deletion 13q, all evaluated with high-resolution banding, contributed to a more reliable mental and growth prognosis in such patients.     

A recognisable behavioural phenotype associated with terminal deletions of the short arm of chromosome 8

We report the clinical findings in 5 patients with a terminal deletion of the short arm of chromosome 8. Mild developmental delay was constantly present, in association with microcephaly in 4 of 5 patients. Facial anomalies were mild or absent. A congenital heart defect was present in 3 patients: an atrioventricular septal defect (AVSD) in 2 and an atrial septal defect type II (ASDII) with pulmonary stenosis in one. A highly similar pattern of behavioural difficulties was present in the 3 older children (8–11 years), with outbursts of aggressiveness and destructive behaviour. Follow-up in one patient showed that at the age of 16 years, these behavioural problems had largely disappeared. This observation suggests that in addition to mental retardation, microcephaly, congenital heart defect (typically AVSD), a terminal deletion of chromosome 8p may be associated with a characteristic behavioural phenotype during childhood. Am. J. Med. Genet. 74:515–520, 1997. © 1997 Wiley-Liss, Inc.     

Interstitial deletion of the long arm of chromosome 6 associated with absent pulmonary valve

We report on a newborn infant with a deletion of 6q and absent pulmonary valve. His chromosome constitution was 46,XY,del (6) (q15q21). To our knowledge this is the first case with such combination. Some of his clinical features were found in common in 2 previous 6q- cases with the same breakpoints.