Chromosome 2 Microdeletion Syndrome in a Newborn with Amniotic Band Sequence.

We report a case of amniotic band sequence (ABS) with a 5 kilobase microdeletion at 2p15. The newborn was delivered with absence of the right hand and distal segments of the left digits, consistent with amniotic band sequence. The clinical findings included a lumbar meningocele, bilateral clubfeet, adrenal hypertrophy, microcephaly, and facial dysmorphism. Due to these congenital anomalies not directly associated with ABS, a SNP chromosomal microarray was ordered and identified a 51 kilobase deletion at 2p15, which includes two known genes, USP34 (ubiquitin specific protease 34) and SNORA70B (small nucleolar RNA H/ACA box 70B). The clinical significance of this specific deletion is unknown at this time; however, there have been several case reports with a larger deletion which include these two genes and have been shown to affect neurodevelopment.

Prenatal Identification and Molecular Characterization of Two Simultaneous De Novo Interstitial Duplications of Chromosomal Regions 7p22.1p21.1 and 15q24.1.

The occurrence of simultaneous de novo chromosomal aberrations is extremely rare. Here, we describe two, previously unreported, simultaneous de novo interstitial duplications of chromosomes 7p and 15q. Amniocentesis was completed for a healthy gravida 4 para 3 woman due to her advanced maternal age and concurrent ultrasound findings of partial vermian agenesis, choroid-plexus cysts, and hypoplastic nasal bone. Cytogenetic analysis of cultured amniocytes by conventional chromosome analysis, comparative genomic hybridization, and fluorescence in situ hybridization revealed two interstitial duplications of the chromosomal regions 7p22.1p21.1 and 15q24.1, leading to partial trisomy of 7p and 15q and karyotype 46,XY,dup(7)(p22.1-p21.1),dup (15)(q24.1). Parental chromosomal analysis did not identify any heritable changes, suggesting both mutations were de novo in nature. Postnatal examination of the neonate was significant for low set ears, thick helices, flat nasal bridge, ankyloglossia, and aberrant head shape and size concerning for craniosynostosis. Postnatal MRI was consistent with Dandy-Walker variant showing hypogenesis of the inferior cerebellar vermis. To our knowledge, there are no prenatal or postnatal reports of comparable duplications involving these two regions simultaneously. Continued observation of the neonate may reveal further phenotypic consequences of these two simultaneous de novo interstitial duplications.