Atypical Down Syndrome Features with an Atypical Chromosomal Rearrangement: A Case Report

Khalil HA1*, Almannai M1, Albalwi M2,3,4 and Eyaid W1

1Department of Genetics & Precision Medicine, King Abdullah Specialist Children’s Hospital (KASCH), King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Saudi Arabia 2Department of Pathology and Laboratory Medicine, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Saudi Arabia 3Department of Medical Genomics Research, King Abdullah International Medical Research Center, Ministry of National Guard Health Affairs (MNG-HA), Saudi Arabia 4College of Medicine, King Saud bin Abdulaziz University for Health Sciences (KSAU-HS), Ministry of National Guard Health Affairs (MNG-HA), Saudi Arabia

^*Correspondance to: Hiba Abu Khalil 

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Abstract:

Down Syndrome is one of the most common chromosomal abnormalities occurring in approximately 1 in 700 live births. The majority of cases are attributed to the presence of an additional copy of chromosome 21, resulting in a total chromosome count of 47, as opposed to the typical 46. Distinctive facial characteristics commonly associated with this condition include, but are not limited to, upslanting palpebral fissures, epicanthal folds, protruding tongue, and brachycephaly. Other clinical manifestations encompass hypotonia, intellectual disability, congenital heart defects, among others. In this article, we present the case of a premature neonate delivered at 32 weeks of gestation via emergency cesarean section due to absent diastolic flow. The patient’s prenatal history was significant for intrauterine growth restriction. Following birth, the patient displayed very subtle dysmorphic features, notably upslanting palpebral fissures, without additional features suggestive of Down syndrome. Chromosomal analysis was subsequently requested, revealing an isodicentric chromosome 21 (46, XX idic(21)(q22.3). Array Comparative Genomic Hybridization (CGH) was also performed, revealing a concurrent duplication of the majority of chromosome 21 [21p11. 2q22.3(7761419_41294939)] and a 4.5 Mb deletion of the long arm of chromosome 21, specifically 21q22.3 (41295017_46677460).

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Cite the Article:

Khalil HA, Almannai M, Albalwi M, Eyaid W. Atypical Down Syndrome Features with an Atypical Chromosomal Rearrangement: A Case Report. Ann Clin Case Rep. 2024; 9: 2575..