Elidrissi Errahhali Manal, Elidrissi Errahhali Mounia, Ramdani Sara, Lhousni Saida, Benajiba Noufissa, Rkain Maria, Babakhouya Abdeladim, Elouali Aziza, Ghanam Ayad, Amrani Rim, Messaoudi Sahar, Ayyad Anass, Oneib Bouchra, Mimouni Ahmed, Saadi Hanane, Allaoui Sanae, Ouarzane Meryem, Guichet Agnès, Charif Majida, Boulouiz Redouane, Bellaoui Mohammed
Genetics Unit, Medical Sciences Research Laboratory, Faculty of Medicine and Pharmacy, University Mohammed Premier, Oujda, Morocco; BRO Biobank, Faculty of Medicine and Pharmacy, University Mohammed Premier, Oujda, Morocco.
Genetics Unit, Medical Sciences Research Laboratory, Faculty of Medicine and Pharmacy, University Mohammed Premier, Oujda, Morocco.
Arch Pediatr. 2024 Feb;31(2):112-116. doi: 10.1016/j.arcped.2023.10.002. Epub 2024 Jan 22.
Chromosomal abnormalities are the main cause of birth defects, intellectual disability, and miscarriages. They contribute to significant human morbidity and infant mortality. Here we report for the first time the chromosomal abnormalities encountered in the population of Eastern Morocco. Furthermore, we describe a new case of a de novo partial trisomy 13q combined with a terminal deletion in an 11-day-old girl.
From November 2015 to March 2022, 195 patients from the BRO Biobank who were clinically suspected of having chromosomal abnormalities were referred to the cytogenetics laboratory of the Genetics Unit of the Faculty of Medicine and Pharmacy of Oujda for cytogenetic study. Karyotyping analysis was performed on peripheral blood samples using standard R banding techniques. To identify single-nucleotide polymorphism (SNP) and copy number variants (CNVs), Illumina SNP array was used.
Among 195 studied cases, 32 (16.4 %) had abnormal karyotypes, of which 12 cases had numerical aberrations while 20 cases had structural aberrations. The most common numerical aberrations were Turner syndrome and Down syndrome followed by Edward, Patau, and Klinefelter syndromes. For structural aberrations, translocations were the most common, followed by derivative chromosomes, inversions, deletions, and an addition on chromosome 13 identified in an 11-day-old girl. To further characterize this addition, SNP array was carried out and revealed a 58.8-Mb duplication in region 13q14.3q34 associated with a 1-Mb deletion in region 13q34. Follow-up parental chromosomes analysis showed normal karyotypes for the parents, confirming that this partial trisomy 13q was de novo. Comparison of the phenotype associated with this novel duplication on chromosome 13q with those previously reported confirmed the considerable variability in the phenotype of the patients with partial trisomy 13q.
This study provided the first report on chromosomal abnormalities in Eastern Morocco and it enriched the phenotype spectrum of partial trisomy 13q and further confirmed the genotype-phenotype correlations. Furthermore, these findings justify the need to set up microarray comparative genomic hybridization techniques in Morocco for better genetic diagnosis.
染色体异常是出生缺陷、智力残疾和流产的主要原因。它们导致了严重的人类发病率和婴儿死亡率。在此，我们首次报告了摩洛哥东部人群中遇到的染色体异常情况。此外，我们描述了一例11天大女孩的新发部分13号染色体三体合并末端缺失的新病例。
2015年11月至2022年3月，来自BRO生物银行的195例临床怀疑有染色体异常的患者被转诊至乌季达医学与药学院遗传学系细胞遗传学实验室进行细胞遗传学研究。使用标准R显带技术对外周血样本进行核型分析。为了鉴定单核苷酸多态性（SNP）和拷贝数变异（CNV），使用了Illumina SNP芯片。
在195例研究病例中，32例（16.4%）核型异常，其中12例为数目畸变，20例为结构畸变。最常见的数目畸变是特纳综合征和唐氏综合征，其次是爱德华兹综合征、帕陶综合征和克兰费尔特综合征。对于结构畸变，易位最为常见，其次是衍生染色体、倒位、缺失，以及在一名11天大女孩中发现的13号染色体上的一个额外片段。为了进一步表征这个额外片段，进行了SNP芯片分析，结果显示13q14.3q34区域存在58.8 Mb的重复，与13q34区域1 Mb的缺失相关。对父母染色体的后续分析显示父母核型正常，证实了这种部分13号染色体三体是新发的。将与13号染色体上这种新重复相关的表型与先前报道的表型进行比较，证实了部分13号染色体三体患者表型的显著变异性。
本研究首次报道了摩洛哥东部的染色体异常情况，丰富了部分13号染色体三体的表型谱，并进一步证实了基因型与表型的相关性。此外，这些发现证明了在摩洛哥建立微阵列比较基因组杂交技术以进行更好的基因诊断的必要性。
