We report, to the best of our knowledge, only the fourth case of trisomy for the interstitial region 7q22-*q31.2 and two cases of trisomy 7q34-*qter, the most distal region yet to be described.Case reports CASE 1 Case 1, born 8.12.87, was the first born of twins to a

Two new classes of common fragile site seen in chromosomes from blood lymphocyte cultures are reported. The first class is induced in bands 1q42 and 19q13 by 5-azacytidine (5-AZA). Maximum induction of these fragile sites occurs when the 5-AZA is added 5-8h prior to harvest. The second class is induced in bands 6q13, 9p21, and 10q21 by bromodeoxyuridine (BrdU). In this instance maximum induction occurred if the BrdU was added 4-6h prior to harvest. The known fragile sites, both rare and common, are summarised.

We report on a 6-year-old boy referred for cytogenetics study. A few non-specific features were observed in the newborn: hypotonia, failure to thrive, seizures, pre-auricular skin tags. Cat-like cry was not identified. No remarkable facial dysmorphism, gastrointestinal, respiratory or cardiac abnormalities were identified. At age 4 years, speech and motor skill delays were apparent. Karyotyping and FISH analysis revealed a de novo rearranged chromosome 5p, with subtelomeric deletion of 5p and a duplication of the cri-du-chat critical region. Array CGH using sub-megabase resolution tiling-set (SMRT) array followed by FISH analysis with labeled BACs showed a deletion of 5pter to 5p15.31 (0-6.9 Mb) and an inverted duplication of the greater part of 5p15.31 to the distal end of 5p14.3 (6.9-19.9 Mb). Although very rare, inverted duplications with terminal deletion (inv dup del) have been reported at different chromosomal ends. Our finding adds a second patient of inv dup del 5p to this growing list, and the potential causative mechanisms for this rearrangement are discussed. Review of the mapping information of cri-du-chat patients and the comparison with a previously reported patient suggested that the critical region for cat-like cry is located within a 0.6 Mb region.

We describe a mother and two sons with a 6-Mb terminal deletion of the short arm of the X chromosome. The breakpoint was localized to a region between DXS6837 and sAJ243947 in Xp22.33. The two boys were shown to be deleted for the SHOX and ARSE genes on their X chromosome. Both sons were short in stature and showed mild to moderate skeletal abnormalities. The most significant findings in the younger son were severe learning disabilities and attention deficit hyperactivity disorder (ADHD). The older son tested in the mild mental retardation range and was also affected by ADHD. The VCX-A gene, implicated recently in X-linked nonspecific mental retardation, was found to be present in both boys. The mother's stature was greater than one standard deviation below her target height and she had only subtle radiographic evidence of Madelung deformity. Our findings indicate that loss of the Xp22.3 region is not always associated with the classic presentations of Léri-Weill syndrome, or chondrodysplasia punctata, and that one or more genes involved in learning and attention may reside in Xp22.3.

Two unrelated children with partial deletion of the long arm of a chromosome no. 5 are reported. The boy presented with severe hypotonia, developmental delay, and a few minor defects of the face including frontal bossing, antimongoloid slant of the palpebral fissures, depressed nasal bridge and bilateral epicanthal folds. With age, his hypotonia has improved. The parents have normal chromosomes; the mother has a 9qh+ variant. The second patient, a girl, presented at birth with multiple congenital anomalies including cleft palate, epicanthal folds, anteverted nostrils, horseshoe kidneys and club feet. At 4 years of age, she was small and severely retarded. The normal parents and the normal sister showed no chromosomal abnormalities. Gene mapping studies in both patients failed to define a specific gene locus to the deleted chromosome regions. Including these two patients, there appear to be only three reported cases of patients with 5q deletion. A comparative description of the third patient is included in this report. There are some clinical similarities but these are inadequate to identify a clinical syndrome. This perhaps is explained by some quantitative and qualitative differences in the deletions.