Pure 21q22.3 deletion identified in a patient with mild phenotypic features

A de novo pure 21q22.3 deletion in a 9-year-old boy with buried penis: a case report and literature review

21q deletion has been associated with a wide range of clinical signs, from very mild to severe phenotypes, and with the progress of genetic technology, more patients with this deletion are being diagnosed. This study reports on a 9-year-old boy with a terminal deletion of 4.5 Mb on chromosome 21 in the locus of chr21: 43531239-48119895 (GRCh37/hg19). Dark skin, a buried penis, small testes, dental caries, microcephaly, a low auricle, mental and intellectual retardation, balance disorder and pituitary and callosum dysplasia were observed. The results of a literature review and observation of similar abnormalities, including hypoplasia of corpus callosum, in two patients with non-overlapping deletion regions suggest that there are multiple gene loci regulating brain development on 21q. By comparing the overlapped deletion region in 21q22.3 cases of brain anomalies and/or gonadal dysgenesis, we concluded there were two overlapped microdeletion regions (chr21:43531239-43792093 and chr21:46625055-46884297) that may be related to brain and gonadal development. The same 16.49 Mb deletion of chr21:31578129-48119895 (GRCh37/hg19) was shared in 10 cases, and 24 cases shared the same 5.59 Mb deletion of chr21:42478130-48119895 (GRCh37/hg19) in DECIPHER (Database of Chromasomal Imbalance and Phenotype in Humans using Ensembl Resources), suggesting these were two commonly deleted regions of pure partial 21q. Those patients with the same breakpoints had different phenotypes suggesting the heterogeneity of 21q deletion.

Genotype-Phenotype Analysis of 8q24.3 Duplication and 21q22.3 Deletion in a Chinese Patient and Literature Review

INTRODUCTION

Copy number variants (CNVs) are responsible for many patients with short stature of unknown etiology. This study aims to analyze clinical phenotypes and identify pathogenic CNVs in a patient with short stature, intellectual disability, craniofacial deformities, and anal imperforation.

METHODS

G-banded karyotyping and chromosomal microarray analysis (CMA) was used on the patient to identify pathogenic causes. Fluorescence in situ hybridization (FISH) was applied to explore the abnormal genetic origin. Literatures were searched using identified CNVs as keywords in the PubMed database to perform genotype-phenotype analysis.

RESULTS

Cytogenetic analysis revealed a normal karyotype 46,XY. CMA detected a 6.1 Mb duplication at 8q24.3 and a 3.6 Mb deletion at 21q22.3. FISH confirmed that the abnormal chromosomes were inherited from paternal balanced translocation. We compared phenotypes of our patient with 6 patients with 8q24.3 duplication and 7 cases with 21q22.3 deletion respectively.

CONCLUSIONS

A novel 8q24.3 duplication and 21q22.3 deletion was identified in a Chinese patient. Genotype-phenotype analysis demonstrated that patients with 8q24.3 duplication and 21q22.3 deletion had specific facial features, intellectual disability, short stature, and multiple malformations.

Brazil's Craniofacial Project: Different approaches on orofacial clefts and 22q11.2 deletion syndrome

This article reports the present situation of Brazilian health care in genetics for Orofacial Cleft (OFC) and 22q11.2 Deletions Syndrome (22q11.2 DS) based on research conducted by Brazil's Craniofacial Project (BCFP). Established in 2003, BCFP is a voluntary and cooperative network aiming to investigate the health care of people with these diseases and other craniofacial anomalies. The initiatives and research results are presented in four sections: (a) a comprehensive report of the Brazilian public health system in craniofacial genetics; (b) multicentric studies developed on OFC and 22q11.2 DS; (c) education strategies focused on addressing these conditions for both population and health-care professionals; and (d) the nosology through the Brazilian Database on Craniofacial Anomalies (BDCA). Since 2006, BDCA uses a standardized method with detailed clinical data collection, which allows for conducting studies on nosology, genotype-phenotype correlations, and natural history; data can also contribute to public policies. Currently, the BDCA stores data on 1,724 individuals, including 1,351 (78.36%) who were primarily admitted due to OFC and 373 (21.63%) with clinical suspicion of 22q11.2 DS. Chromosomal abnormalities/genomic imbalances were represented by 92/213 (43.19%) individuals with syndromic OFC, including 43 with 22q11.2 DS, which indicates the need for chromosomal microarray analysis in this group. The nosologic diversity reinforces that monitoring clinical is the best strategy for etiological investigation. BCFP's methodology has introduced the possibility of increasing scientific knowledge and genetic diagnosis of OFC and 22q11.2 DS to in turn improve health care and policies for this group of diseases.