Inherited dup(17)(p11.2p11.2): expanding the phenotype of the Potocki-Lupski syndrome.

Potocki-Lupski syndrome (PTLS, OMIM: 610883) is a microduplication syndrome characterized by infantile hypotonia, failure to thrive, cardiovascular malformations, developmental delay, intellectual disability, and behavior abnormalities, the latter of which can include autism spectrum disorder. The majority of individuals with PTLS harbor a de novo microduplication of chromosome 17p11.2 reciprocal to the common recurrent 3.6 Mb microdeletion in the Smith-Magenis syndrome critical region. Here, we report on the transmission of the PTLS duplication across two generations in two separate families. Individuals in these families presented initially with developmental delay, behavior problems, and intellectual disability. We provide a detailed review of the clinical and developmental phenotype of inherited PTLS in both families. This represents the second report (second and third families) of PTLS in a parent-child pair and exemplifies the under-diagnosis of this and likely other genetic conditions in adults with intellectual disability and/or psychiatric disorders.

Methylation analysis of 79 patients with growth restriction reveals novel patterns of methylation change at imprinted loci.

This study was an investigation of 79 patients referred to the Wessex Regional Genetics Laboratory with suspected Russell-Silver Syndrome or unexplained short stature/intra uterine growth restriction, warranting genetic investigation. Methylation status was analysed at target sequences within eleven imprinted loci (PLAGL1, IGF2R, PEG10, MEST1, GRB10, KCNQ1OT1, H19, IGF2P0, DLK1, PEG3, NESPAS). Thirty seven percent (37%) (29 of 79) of samples were shown to have a methylation abnormality. The commonest finding was a loss of methylation at H19 (23 of 29), as previously reported in Russell-Silver Syndrome. In addition, four of these patients had methylation anomalies at other loci, of whom two showed hypomethylation of multiple imprinted loci, and two showed a complete gain of methylation at IGF2R. This latter finding was also present in five other patients who did not have demonstrable changes at H19. In total, 7 of 79 patients showed a gain of methylation at IGF2R and this was significantly different from a normal control population of 267 individuals (P=0.002). This study in patients with growth restriction shows the importance of widening the epigenetic investigation to include multiple imprinted loci and highlights potential involvement of the IGF2R locus.

De Barsy syndrome: a review of the phenotype.

De Barsy syndrome is a rare, autosomal recessive syndrome characterised by a progeria-like appearance with distinctive facial features and cutis laxa. Ophthalmological, orthopaedic and neurological abnormalities are also typically present. The syndrome was first described by de Barsy et al. in 1967 and since that time approximately 27 further cases have been reported worldwide. We present a case that demonstrates the typical clinical and histological features of de Barsy syndrome. A female infant, the second child of first-cousin parents from a multiply consanguineous family of Pakistani origin, presented at birth with growth retardation, cutis laxa and a progeria-like appearance. She had thin, overlapping fingers and adducted thumbs, blue sclerae, cloudy corneas and myopia. She has failed to thrive and has marked developmental delay and abnormal athetoid movements. During the first year of life she developed pectus excavatum and her facial appearance became more aged. To our knowledge there are no previous reports of de Barsy syndrome in individuals of Pakistani origin.