Interstitial deletion at 11q14.2-11q22.1 may cause severe learning difficulties, mental retardation and mild heart defects in 13-year old male

The prevalence of autism among children with albinism

BACKGROUND

The association between Autism spectrum disorders (ASD) and visual impairment has been mentioned in the literature. The aim of our study was to investigate the prevalence of autism among children with albinism compared to the prevalence of ASD in children with visual impairment secondary to other causes.

METHODS

Retrospective study of children with albinism from January 2015 to December 2020. A control group was created with children with early onset visual impairment of similar visual range and age, secondary to diagnosis other than albinism. Patients with associated Autism were identified in both groups.

RESULTS

Seven hundred and eight children aged 1-18 years with visual impairment were included in the study. 401 children had a diagnosis of albinism, of whom 14 were also diagnosed with ASD. In the control group, composed of 307 patients, only 3 had ASD (p: 0·03).

CONCLUSIONS

The prevalence of ASD in patients with albinism was 1 in 28, while in children with visual impairment from other causes was 1 in 102. We aim to raise awareness of the higher prevalence of autism in children diagnosed with albinism in order to reach earlier diagnosis and support.

Replication stress in mammalian embryo development, differentiation, and reprogramming

Duplicating a genome of 3 billion nucleotides is challenged by a variety of obstacles that can cause replication stress and affect the integrity of the genome. Recent studies show that replication fork slowing and stalling is prevalent in early mammalian development, resulting in genome instability and aneuploidy, and constituting a barrier to development in human reproduction. Genome instability resulting from DNA replication stress is a barrier to the cloning of animals and to the reprogramming of differentiated cells to induced pluripotent stem cells, as well as a barrier to cell transformation. Remarkably, the regions most impacted by replication stress are shared in these different cellular contexts, affecting long genes and flanking intergenic areas. In this review we integrate our knowledge of DNA replication stress in mammalian embryos, in programming, and in reprogramming, and we discuss a potential role for fragile sites in sensing replication stress and restricting cell cycle progression in health and disease.

De novo interstitial deletion of 11q14.3q22 in a boy with mild intellectual disability and short stature

BACKGROUND

Interstitial deletions of the 11q region are infrequent. Nonrecurrent chromosomal rearrangements are observed with high variability in size and precise breakpoints of the deleted area. Moreover  heterogeneous clinical findings are observed in those harboring 11q interstitial deletions. Main clinical features associated with these deletions include mild dysmorphic findings  intellectual disability and moderate developmental or speech delay .

METHOD

Conventional high-resolution karyotyping along with microarray studies were performed for the index patient  who was found to be a carrier of a de novo interstitial deletion in the long arm of chromosome 11  which is located between the 11q14 and 11q22 band regions. We also investigated the homologous chromosome with next-generation sequencing technology to search for unmasked recessive variants in genes on the nondeleted contralateral allele.

RESULTS

Cytogenetic analysis revealed a de novo interstitial deletion on the long arm of chromosome 11  46 XY del(11) (q14q22). Microarray analysis confirmed the deletion of 11.2 Mb in length  mapping from 11q14.3 to 11q22.2 [arr (GRCh37) 11q14.3q22.1(90549863_101833022)x1 dn]. Whole-exome sequencing did not detect any other genetic variant (single nucleotide variant ) on the nondeleted allele.

CONCLUSION

This study gave us the opportunity for an attempt to define the smallest region of overlap for frequently observed clinical findings by reviewing the literature.

A Novel de Novo Paracentric Inversion [inv(20)(q13.1q13.3)] Accompanied by an 11q14.3-q21 Microdeletion in a Pediatric Patient with an Intellectual Disability

A novel de novo paracentric inversion of the long arm of chromosome 20 [inv(20)(q13.1q13.3)], detected by conventional karyotyping in a 14-year-old boy with mental retardation is described. Further investigation by array comparative genomic hybridization (aCGH) revealed that the 20q inversion was not accompanied by microdeletions/microduplications containing disease-associated genes near or at the breakpoints. Two deletions at chromosomal regions 11q14.3q21 and 20q12 of 4.5 and 1.97 Mb size, respectively, containing important online Mendelian inheritance in man (OMIM) genes, were detected. The 4.5Mb 11q14.3q21 microdeletion was contained within a region that is involved, in most of the reported cases, with the interstitial 11q deletion and may be related to the mental retardation and developmental delay present in the patient. On the other hand, the published data about the 20q12 microdeletion are very few and it is not possible to correlate this finding with our patient’s phenotype. This case report contributes to the description of a new chromosomal entity, not previously reported, and is therefore important, especially in prenatal diagnosis and management of patients. Array comparative genomic hybridization has proven a useful technique for detecting submicroscopic rearrangements and should be offered prenatally, especially in cases of de novo karyotypically balanced chromosomal inversions or translocations in order to unveil other unbalanced chromosomal abnormalities such as deletions and amplifications.