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The Prader-Willi/Angelman Critical Region (PWACR; Chromosome 15q11-13) is of interest as a potential locus for genes conferring susceptibility to autism spectrum disorders (ASD). This report describes a female proband referred for evaluation of a possible ASD. Genetic analyses indicated that the proband, her father and one of her sisters, carried a paternally derived interstitial duplication involving 15q11-13. The proband showed evidence of ASD (PDD-NOS), borderline mental retardation, mild hypotonia and joint laxity. Her father and her sister were of normal intelligence and neither was thought to have an ASD, although speech/language difficulties and some autistic type behaviours were reported to have been present early in the development of the sister. This is one of the first reports of a child with a paternal duplication and an autism spectrum disorder. More research is required to determine whether paternally derived duplications that involve 15q11-13 are associated with developmental impairments.

Small ring (X) chromosomes lacking the XIST gene at Xq13.2 have been associated with a severe phenotype that includes mental retardation, facial dysmorphism and congenital abnormalities. It has been hypothesised that the loss of XIST results in functional disomy for the sequences contained in the ring. We studied 47 females with a 45,X/46,r(X) karyotype and found seven to have an XIST-negative ring. Only one of the seven patients had the severe phenotype. The remaining six patients had physical phenotypes consistent with Turner syndrome. The rings were characterised cytogenetically and molecularly. The severe phenotype in one patient can be explained by the absence of XIST expression, the relatively large amount of Xp material in the ring and, possibly, the concomitant maternal uniparental isodisomy. We propose three explanations for the unexpectedly mild phenotypes in the remaining six patients; (1) the rings contained limited amounts of X-chromosome material, and sequences that, when functionally disomic, result in a severe phenotype were absent; (2) mosaicism resulting in the absence of the ring from tissues, such as the brain, which are important in the severe phenotype and (3) the presence of an inactive X in some tissues at some time, exemplified by the demonstration of XIST expression in one patient. [ABSTRACT FROM AUTHOR]

Presents information on a study which discussed the possible causal relationship between Hirschsprung's disease and Waardenburg's syndrome in an infant. Disorders associated with an increased risk of Hirschsprung's disease; Association of congenital deafness with Hirschsprung's disease; Information on the physical findings on the patient.

We report the clinical, cytogenetic, and molecular findings in a family in which a t(Y;15)(p11.2;q12) is segregating. The Y chromosome breakpoint disrupts the DYZ5 sequence containing the TSPY genes that are exclusively expressed in the testes while the chromosome 15 breakpoint is within the GABRG3 gene. The father and his son who both carried the balanced form of the translocation are clinically normal. A daughter who carried the der Y had the clinical features of Prader-Willi syndrome while a son who carries the der 15 has mild developmental delay and hypogonadism. The relationship of the translocation to the clinical phenotypes is discussed., (Copyright 2003 Wiley-Liss, Inc.)