Subtelomeric trisomy 21q: a new benign chromosomal variant

Autism spectrum disorder, anxiety and severe depression in a male patient with deletion and duplication in the 21q22.3 region: A case report

In this report, a patient carrying a 650 kb deletion and a 759 kb duplication of chromosomal 21q22.3 region was described. Facial dysmorphic features, hypotonia, short stature, learning impairment, autism spectrum disorder, anxiety and depression were observed clinical characteristics. Mentioned copy number variants were the shortest in length reported so far. The current study hypothesized that the presence of a susceptibility locus for autism spectrum disorder associated with depression and anxiety may be located in a 200 kb region between the PCNT and PRMT2 genes. The current study aimed to provide insight into the human genome morbidity map of chromosome 21.

Language ENvironment Analysis (LENA) in Phelan-McDermid Syndrome: Validity and Suggestions for Use in Minimally Verbal Children with Autism Spectrum Disorder

Phelan-McDermid syndrome (PMS) is a single-locus cause of developmental delay, autism spectrum disorder, and minimal verbal abilities. There is an urgent need to identify objective outcome measures of expressive language for use in this and other minimally verbal populations. One potential tool is an automated language processor called Language ENvironment Analysis (LENA). LENA was used to obtain over 542 h of audio in 18 children with PMS. LENA performance was adequate in a subset of children with PMS, specifically younger children and those with fewer stereotypic vocalizations. One LENA-derived language measure, Vocalization Ratio, had improved accuracy in this sample and may represent a novel expressive language measure for use in severely affected populations.

Novel UBE3A mutations causing Angelman syndrome: different parental origin for single nucleotide changes and multiple nucleotide deletions or insertions

Angelman syndrome (AS) is a genetic disorder caused by a deficiency of UBE3A imprinted gene expression from the maternal chromosome 15. In 10% of AS cases the genetic cause is a mutation affecting the maternal copy of the UBE3A gene. In two large Spanish series of clinically stringently selected and nonstringently selected patients, we have identified 11 pathological mutations--eight of them novel mutations--and 14 sequence changes considered polymorphic variants. Remarkably, single nucleotide substitutions are more likely to be inherited, while multiple nucleotide deletions or insertions are less frequently inherited, thus indicating that single nucleotide substitutions are more likely to originate from the paternal germline. Additionally, there seems to be a different distribution of nucleotide changes and multiple nucleotide deletions or insertions along the UBE3A gene sequence.

Two cases of deletion 2q37 associated with segregation of an unbalanced translocation 2;21: choanal atresia leading to misdiagnosis of CHARGE syndrome

CONTEXT

The phenotypic variability of patients with syndromes presenting with dysmorphism makes clinical diagnosis difficult, leading to an exhaustive genetic study to determine the underlying mechanism so that a proper diagnosis could be established.

OBJECTIVE

To genetically characterize siblings, the older sister diagnosed with Albright hereditary osteodystrophy and the younger one with CHARGE syndrome.

DESIGN

Clinical case report.

METHODS

Clinical, biochemical, and radiological studies were performed on the family. In addition, molecular genetic studies including sequencing of GNAS, typing of microsatellites on 2q and 21q, and multiplex ligation-dependent probe amplification of subtelomeric regions were performed, as well as confirmatory fluorescent in situ hybridization analysis.

RESULTS

The genetic analysis revealed that both sisters presented a 2q37 deletion due to the maternal unbalanced segregation of a 2;21 translocation.

CONCLUSIONS

This is the first report of a 2q37 deletion where differential diagnosis of CHARGE syndrome is needed due to the appearance of choanal atresia.

Mosaic 22q13 deletions: evidence for concurrent mosaic segmental isodisomy and gene conversion

Although 22q terminal deletions are well documented, very few patients with mosaicism have been reported. We describe two new cases with mosaic 22q13.2-qter deletion, detected by karyotype analysis, showing the neurological phenotype of 22q13.3 deletion syndrome. Case 1 represents an exceptional case of mosaicism for maternal 22q13.2-qter deletion (45% of cells) and 22q13.2-qter paternal segmental isodisomy (55% of cells). This complex situation was suspected because cytogenetic, FISH and array-CGH analyses showed the presence of an 8.8 Mb mosaic 22q13.2-qter deletion, whereas microsatellite marker analysis was consistent with maternal deletion without any evidence of mosaic deletion. Molecular analysis led to the definition of very close, but not coincident, deletion and uniparental disomy (UPD) break points. Furthermore, we demonstrated that the segmental UPD arose by gene conversion in the same region. In Case 2, mosaicism for a paternal 8.9 Mb 22q13.2-qter deletion (73% of cells) was detected. In both patients, the level of mosaicism was also verified in saliva samples. We propose possible causative mechanisms for both rearrangements. Although the size of the deletions was quite similar, the phenotype was more severe in Case 2 than in Case 1. As maternal UPD 22 has not been generally associated with any defects and as the size of the deletion is very similar in the two cases, phenotype severity is likely to depend entirely on the degree of mosaicism in each individual.