We present two unrelated children with the de novo interstitial deletion of the proximal segment of the long arm of chromosome 1 (lq21-23-lq2.5). Comparison of the phenotypic characteristics of these two patients with those of two previously described patients with similar deletion confirms the existence of the proximal Iq deletion syndrome. The characteristics of this newly recognized deletion syndrome include pre-and postnatal growth retardation; severe psychomotor retardation; microbrachycephaly ; sparse, fine scalp hair and eyebrows; cleft lip and palate; hernias; genitalia defects; small hands and feet; and clinodactyly of the fifth fingers.
A partial duplication of the distal segment of the long arm of chromosome 5 (q31 leads to qter) was observed in an infant with congenital malformations and dysmorphic features. The phenotypically normal father had a balanced translocation between the long arm of chromosome 5 and the short arm of chromosome 9: 46,XY,t(5;9)(q31;p24). The clinical and cytogenetic data obtained from six patients with partial duplications of two different long arm segments of chromosome 5 suggest that partial duplication of the distal long arm of chromosome 5 is associated with microcephaly, hypertelorism, epicanthus, strabismus, large upper lip, low-set, dysplastic ears, in addition to growth and psychomotor retardation. Partial duplication of the proximal part of the long arm of chromosome 5, on the other hand, is associated mainly with musculoskeletal abnormalities including muscle hypotrophy and hypotonia, scoliosis, lordosis, pectus carinatum, cubitus valgus, and genu valgum, in addition to psychomotor retardation. The dysmorphic features in this latter group include a bulging forehead, short nose, thick upper lip, low-set protruding ears and tapering, thin fingers.
We present four children with a ring chromosome 6. Clinically, these cases are quite variable. A review of ten previously reported cases also suggests difficulty of phenotype-karyotype correlation in patients with a ring 6.
This communication describes an infant with growth and psychomotor retardation and severe congenital malformations, who was found to have an interstitial deletion of the long arm of chromosome 8: 46,XY,del(8) (q13q22). Comparison with the only other previously reported patient with a deletion of a similar chromosomal segment suggested that deletion of the long arm of chromosome 8 may constitute a clinically recognizable syndrome.
Characteristic features of the Williams syndrome were observed in a mother and her presumably dizygotic twin daughters, suggesting either an X‐linked dominant, autosomal dominant or multifactorial inheritance in this pedigree. The Williams syndrome generally has been thought to have a sporadic occurrence. The rare familial occurrence, however, suggests a possible heterogeneity in its etiology and also points out the importance of careful examination of the other family members for proper genetic counseling.
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