A female infant who died at 2 years of age with growth and psychomotor retardation, wide anterior fontanelle, downward slanting palpebral fissures, large, simple ears, joint dislocation/contractures, recurrent infections, and severe pulmonary hypertension was found to have a de novo 7p+ chromosome. The G banding pattern was suggestive of a triplication of 7p2l.3 and 7p22; results of fluorescence in situ hybridisation studies using a chromosome 7 specific library, a subtelomeric 7p repeat (109A6), and yeast artificial chromosome clones 786gl and 850al, which are respectively associated with the (CA)n repeat markers D7S517 and D7S513, supported the cytogenetic interpretation and showed that the middle repeat was inverted. The patient's phenotype was consistent with the 7p duplication syndrome, allowing for the effects of the extra burden introduced by the partial tetrasomy. The present rearrangement may have resulted from several meiotic events occurring at the four chromatid stage, namely an unequal crossover or interhomologue translocation with points of exchange at 7p22 and 7plS followed by the inverted insertion of 7p2l.3-p2l.2 at the former breakpoint junction; moreover, a further duplication including D7S517 within the terminal 7p22 band is also required.(7Med Genet 1998;35:78-80)

An 8‐month‐old boy with multiple malformations and psychomotor retardation was found to have a de novo t(4;5)(q3100;q2200) with del(5)(ql500q2200). The phenotypical comparison with 10 similar monosomic cases from the literature led us to tentatively delineate a 5q monosomy syndrome and to postulate the band 5ql5 as the correspondent critical segment.

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A 19‐year‐old female patient with gonadal dysgenesis and a de novo t(X;17) (Xp17q;Xq17p) is described. Since the critical segment Xq13 → q26 was intact, this case is a further exception to the critical region hypothesis.