Clinical manifestations in trisomy 9 mosaicism

Abstract

Trisomy 9 is a rare chromosome abnormality which can occur in a mosaic or nonmosaic state with similar clinical features. The authors present a male with mosaic trisomy 9 from birth to 6 months of life. Clinical manifestations included growth retardation, facial dysmorphism with marked hemi facial hypoplasia and facial asymmetry, single palmar flexion crease, retro calcaneovalgus feet, atrial septal defect, undescended testes and hypospadia. He had several episodes of seizures and ultrasound examination described severe ventriculomegaly, with poorly differentiated parenchyme. These findings are compared to the other previously described cases of trisomy 9 mosaicism through a review of literature.

Clinical and cytogenomic characterization of de novo trisomy 9 mosaicism in an Egyptian family: phenotype/karyotype correlation

“…Our patients had prenatal onset of growth deficiency similar to that reported by Jones et al; Pruksanusak et al and Pejcic et al [2,5,12]. They presented with delayed milestones and dysmorphic features comprising triangular face, recession of anterior hair line, downwards slanting of eyes, bulbous nose, low set ears, micrognathia, short neck and clinodactly of 5 th finger in right hand.…”

“…Children born with T9 mosaicism usually survive into adulthood [2,3]. T9 mosaicism usually present with a low birth weight and a wide range of developmental disabilities, dysmorphism and organ abnormalities, though the phenotype may differ widely between the patients [4,5]. T9 mosaicism is characterized by growth retardation, developmental delay, delayed communication and speech and learning difficulties.…”

“…Abnormalities involve different organ systems such as the brain and CNS, heart, kidneys, digestive tract, muscles (hypertonia), genital and urinary tract [5,7]. However, growth retardation and developmental delay were mainly less severe in patients with a low level of T9 mosaicism.…”

Case report of a pseudo‐isodicentric chromosome 9 resulting in mosaic trisomy 9

“…Our patient's clinical findings of hypotonia, laryngomalacia, feeding difficulties, and short stature have been reported in several other trisomy 9 cases. 8,9 Although clinical findings in this case are consistent with mosaic trisomy 9, the pregnancy was complicated by CMV infection in the 3rd trimester, increasing the risk of congenital CMV infection. Some of the symptoms overlap with other reported cases of mosaic trisomy 9 patients; however, our patient repeatedly tested negative for CMV, supporting the pseudo-isodicentric chromosome 9 as the cause of her phenotype.…”

Trisomy 9 Mosaicism Syndrome in a Female Child

“…Fluorescence in-situ hybridization analysis of autopsies from patients previously described as non-mosaics revealed the presence of both euploid and trisomy 9 cells when both blood and fibroblast cells were analyzed, indicating that these patients were born in the mosaic form [3]. Clinical symptoms vary greatly in range and severity, depending on the percentage of cells with the extra chromosome 9 [5]. The main features of T9MS are craniofacial features with a bulbous nose, microphthalmia, dislocated limbs, and other anomalies of skeletal, cardiac, genitourinary, and central nervous systems.…”