Mosaic trisomy 22: Report of a patient with normal intelligence

Trisomy 22 Mosaicism from Prenatal to Postnatal Findings: A Case Series and Systematic Review of the Literature

BACKGROUND

Among aneuploidies compatible with life, trisomy 22 mosaicism is extremely rare, and only about 25 postnatal and 18 prenatal cases have been described in the literature so far. The condition is mainly characterized by facial and body asymmetry, cardiac heart defects, facial dysmorphisms, growth failure, delayed puberty, and variable degrees of neurodevelopmental delay.

PROBLEM

The scattered information regarding the condition and the dearth of data on its natural history and developmental outcomes restrict genetic counseling, particularly in prenatal settings. Moreover, a prompt diagnosis is frequently delayed by the negative selection of trisomic cells in blood, with mosaicism percentage varying among tissues, which often entails the need for further testing. Purpose/topic: The aim of our work is to provide assistance in prenatal and postnatal genetic counseling by systematically delineating the current knowledge of the condition. This entails defining the prenatal and postnatal characteristics of the condition and presenting novel data from three cases, both prenatally and postnatally. Additionally, we report the developmental outcomes observed in two new patients.

Occurrence of mosaic trisomy 22 and pericentric inversion of chromosome 9 in a patient with a good prognosis

Complete trisomy 22 is a rare chromosomal condition that is incompatible with life. However, mosaic trisomy 22 usually has prolonged survival compatibility and may present a good prognosis depending on the tissues affected. Herein, we described a male patient with the occurrence of mosaic trisomy 22 associated with the inversion of chromosome 9, with karyotype 47, XY, inv (9) (p11q13), + 22 [5] / 46, XY, inv(9) (p11q13) [45] and arr 22q11.1 ~ q13.33(16,417008-51,219,009)x2 ~ 3. It is not possible to infer, in general, the clinical characteristics associated with mosaic trisomy 22. However, the patient presented common clinical features observed in reported cases (in parentheses the percentage observed comparing all reported cases): facial dysmorphia (100%), delay in motor development/growth (82%), cardiac abnormalities (73%), ear abnormalities (55%) and facial and/or body asymmetry (55%), in addition to hypotonia, skin spots, hypoplastic nails. Given the survival and quality of life associated with multidisciplinary treatment, it can be concluded that the patient has a good prognosis. Conclusively, we're presenting the occurrence of mosaic trisomy 22 and chromosome 9 inversion in the patient with favorable prognosis. Thus, this study proposed a guide which should be inserted in databases of rare genetic conditions to help genetic counselors define mosaic trisomy 22 diagnosis.

Lessons from a 30 year follow-up of monozygotic twins with discordant phenotype due to a ring 13 chromosomal mosaicism in one of them

At the 43rd annual meeting of the ASHG in 1993, the senior author reported monozygotic twins with discordant phenotype due to a ring 13 chromosomal mosaic syndrome in one of them. Her major manifestations included: intrauterine growth restriction (IUGR), failure to thrive (FTT), delayed developmental milestones/intellectual disability (DDM/ID), left hemihypoplasia of her body with leg length discrepancy, left profound deafness due to inner ear malformation, telecanthus, dental anomalies mainly on the left side, congenital torticollis due to Klippel-Feil anomaly, 13 ribs, scoliosis, dislocation of the left hip, and distinctive left hand and feet. A blood karyotype at age 3^1/2 was normal. Silver-Russell syndrome was initially suspected; however, at age 4, a karyotype on skin fibroblasts showed a ring 13 chromosomal mosaicism, 46,XX,15s+/46,XX,-13,+r(13),15s+, with a higher frequency on the left side of the body. Since then, we have been involved in the management of this patient for 30 years. This has ultimately allowed us to compare her achievements with her normal monozygotic twin. In this long term follow-up, we want to emphasize the importance of: (a) early recognition of genetic syndromes, especially of mosaicisms, and of early intervention programs, (b) the involvement of different specialists in the management of patients with MCA, and (c) mentioning how familial and socioeconomic issues may limit or enhance the full potential of patients with some genetic disorders.

Mosaic trisomy 22 in a 4-year-old boy with congenital heart disease and general hypotrophy: A case report

BACKGROUND

Trisomy 22 mosaicism is a rare autosomal anomaly with survival compatibility. Recognition of the complete trisomy 22 which is incompatible with life from the mosaic form is critical for genetic counseling. Affected mosaic cases have prevalent clinical presentations such as webbed neck, developmental delay, abnormal ears, cardiac disorders, and microcephaly. Phenotype of these patients is milder than full chromosomal aneuploidy, and the severity of the phenotype depends on the count of trisomic cells. We describe a 4-year-old boy with mosaic trisomy 22 from healthy parents and no family history of any genetic disorders in the pedigree.

METHOD AND RESULTS

The patient had determined dysmorphic clinical features including facial asymmetry, cleft palate, gastroenteritis, hydronephrosis, developmental delay, genital anomalies, dysplastic toenails, flattened nasal bridge, congenital heart defect, hearing loss, cryptorchidism, and hypotonic muscle. He is the first reported with hypothyroidism and larynx wall thickness in worldwide and the first with atrial septal defect (ASD) from Iran. Chromosomal analyses using G-banding indicated a de novo Mos 47,XY,+22(6)/46,XY(44) karyotype with no other chromosomal structural changes.

CONCLUSIONS

Our observations confirm the importance of cytogenetic analyses for determining the cause of congenital anomalies and provide a useful genetic counseling. In addition, due to the fact that some of mosaic trisomy 22 features are unavoidable such as CHD and general hypotrophy, we suggest including echocardiography test for early diagnosis during the clinical assessment.

Noonan syndrome: clinical features, diagnosis, and management guidelines

Noonan syndrome (NS) is a common, clinically and genetically heterogeneous condition characterized by distinctive facial features, short stature, chest deformity, congenital heart disease, and other comorbidities. Gene mutations identified in individuals with the NS phenotype are involved in the Ras/MAPK (mitogen-activated protein kinase) signal transduction pathway and currently explain ∼61% of NS cases. Thus, NS frequently remains a clinical diagnosis. Because of the variability in presentation and the need for multidisciplinary care, it is essential that the condition be identified and managed comprehensively. The Noonan Syndrome Support Group (NSSG) is a nonprofit organization committed to providing support, current information, and understanding to those affected by NS. The NSSG convened a conference of health care providers, all involved in various aspects of NS, to develop these guidelines for use by pediatricians in the diagnosis and management of individuals with NS and to provide updated genetic findings.

Prenatal diagnosis and postnatal follow-up of a child with mosaic trisomy 22 with several levels of mosaicism in different tissues

We report on the case of a patient with mosaic trisomy 22, who was diagnosed prenatally by amniocentesis during the 16(th) week of pregnancy. In the foetus, three trisomic clones were found out of the nine that were analyzed (the other six clones had a 46,XY karyotype). Cytogenetic analysis of cord blood during the 20(th) week of pregnancy showed a normal male karyotype; however, a placental biopsy that was performed at the same time showed 100% and 95% trisomic cells in the chromosomal analysis of direct and long-term cultures, respectively. A follow-up ultrasonographic examination excluded major congenital malformations and the abdominal and cranial circumferences were normal until the 24(th) week of pregnancy. At this point, a deflection of the growth curve occurred and the values were persistently below the 3(rd) centile until birth. After birth, karyotypic and fluorescent in situ hybridisation analyses performed on the fibroblasts of the neonate showed that 3-4% of the cell lines were trisomic, and studies using microsatellite markers showed normal allelic segregation, which excluded uniparental disomy. The period of postnatal follow-up was characterised by a significant growth deficit (height and head circumference were less than the 3(rd) centile) and by mental retardation. The present case is compatible with other earlier reports that showed that the levels of trisomy 22 are tissue-specific and are of little help in establishing the prognosis of the chromosomal abnormality.

Mosaic trisomy 22 associated with total colonic aganglionosis and malrotation

AIMS

Abnormalities of chromosome 22 karyotype have been reported to be associated with both malrotation and aganglionosis. However, although malrotation has been reported to occur in the rare mosaic trisomy 22, Hirschsprung's disease has not. We present a case of mosaic trisomy 22 that presented during the neonatal period with malrotation and total colonic aganglionosis, and we discuss the possible pathogenesis of both conditions in the light of this rare genetic abnormality. The association of total colonic aganglionosis and mosaic trisomy 22 has not previously been reported.

RESULTS

A male neonate with an antenatal diagnosis of de novo mosaic trisomy 22 underwent a laparotomy with correction of malrotation and midgut volvulus on day 3 of life. Rectal biopsy was performed because he had not passed meconium. This revealed Hirschsprung's disease; an ileostomy was formed, and histology confirmed aganglionosis as far as the terminal ileum. At 6 months, a modified Lester Martin Duhamel pull-through was performed. He is showing normal development at follow-up.

CONCLUSIONS

We recommend an increased index of suspicion of Hirschsprung's disease and malrotation in patients with mosaic trisomy 22 until further evidence can establish or exclude a meaningful relationship.