Triploidy mosaicism (45,X/68,XX) in an infant presenting with failure to thrive

Abstract

Triploid mosaicism is a rare aneuploidy syndrome characterized by growth retardation, developmental delay, 3-4 syndactyly, microphthalmia, coloboma, cleft lip and/or palate, genitourinary anomalies, and facial or body asymmetry. In the present report, we describe a 3-month-old female presenting with failure to thrive, growth retardation, and developmental delay. A chromosomal microarray demonstrated monosomy X, but her atypical phenotype prompted further evaluation with a chromosome analysis, which demonstrated 45,X/68,XX mixoploidy. To our knowledge, this is the first report of a patient with this chromosome complement. Mosaicism in chromosomal aneuploidies is likely under-recognized and may obscure the clinical diagnosis. At a time when comparative genomic hybridization and genome sequencing are increasingly used as diagnostic tools, this report highlights the clinical utility of chromosome analysis when a molecular diagnosis is not consistent with the observed phenotype.

Mixoploidy combined with aneuploidy in a 13 year‐old patient with severe multiple congenital abnormalities and intellectual disability

“…In this case however, the triploidy may have been confined to the placenta rather than a true mixoploidy being present in the fetus. Recently, the karyotypic combination observed in our patient has been reported for the first time in a 3‐month‐old girl with failure to thrive, dysmorphic craniofacial features, hypotonia, and left ventricular non‐compaction (Posey et al, ). Our patient, with information available at different ages, demonstrates an even more pronounced clinical phenotype, possibly related to the different level of mosaicism in tissues and organs.…”

Genome‐wide abnormalities in embryos: Origins and clinical consequences

“…88 Additional chromosome aneuploidies were also reported in some patients with 2n/3n mixoploidy. [89][90][91][92][93] In these patients, the peripheral blood lymphocytes are usually diploid and the triploid cell lineage is uncovered by fibroblast analysis. Whether tissue specificity is a consequence of selective elimination of triploid lineage during cellular differentiation remains to be determined.…”

“…While full triploidy is largely incompatible with life, diploid/triploid mosaicism has been well documented in children and young adults, 82‐87 including an 8‐year‐old girl, conceived via assisted reproduction using ICSI 88 . Additional chromosome aneuploidies were also reported in some patients with 2n/3n mixoploidy 89‐93 . In these patients, the peripheral blood lymphocytes are usually diploid and the triploid cell lineage is uncovered by fibroblast analysis.…”

Skeletal and dental abnormalities in patients with sex chromosome aberrations: a systematic case-based review

“…V-shaped maxillary dental arch [24], deep bite [28], facial asymmetry [25] -Mosaicism V-shaped maxillary dental arch [24], plagiocephaly [32], diastemas [31], aggressive periodontitis [31] Short upper limbs [33], short fingers [67], medial displacement of bilateral first toes [32], bilateral clubfoot [65] Structural X chromosome abnormality V-shaped maxillary dental arch [35], open bite [35], supernumerary teeth [35], enamel hypoplasia [35] Short upper limbs [33], atrophy of right upper limb [35] Klinefelter syndrome 47,XXY Impacted teeth [40], open bite [40], enamel defects [40] − 48,XXXY Large palatal torus [42], bimaxillary protrusion [43], open bite [43] Hip dysplasia [55] 48,XXYY − −…”