[Distal 1q monosomy. 2 new cases and description of the syndrome].

In two unrelated girls, each with severe mental deficiency and craniofacial dysmorphism, deletion of chromosome segment 1q4 had occurred de novo. These two observations together with seven others from the literature allow delineation of a syndrome, as follows. Growth retardation is marked at birth and remains beyond the 3rd percentile. Mental retardation is severe. Seizures are frequent. The cry may be unusually high pitched. Craniofacial dysmorphism includes brachymicrocephaly, a round and flat facies, a high forehead with a prominent metopic suture, thin and scarse hair, palpebral fissures slanted upward, hypertelorism and epicanthal folds, a bulbous nose with a flattened nose-bridge, a large and prominent philtrum, well-defined Cupid's bow, and retrognathia. Other malformations include various skeletal malformations, hypospadias with or without cryptorchidism, a consistent feature, and congenital heart disease in a third of the cases. The deletion occurred de novo in 8 out of the 9 cases. The breakpoint is, according to the several authors, in 1q42 or q43.