Trisomy 20 (NON-MOSAIC) Case report FATEMEH HEKMATI “YAS GENERAL WOMAN HOSPITAL, Cytogenetic Lab”

Prevalence of Trisomy 20 Mosaic Non-Mosaic INTRODUCTION Prevalence of Trisomy 20 Mosaic Non-Mosaic less than 200,000 people in the US population Fewer than 40 patients have been described Trisomy 20 mosaicism is a common abnormality found in prenatal diagnosis

Clinical manifestations 1) A variable degree of developmental delay and 2) Mild to moderate intellectual disability, 3) facial dysmorphisms (round face with full cheeks, thick coarse and usually straight hair, laterally arched eyebrows, upward slanting palpebral fissures, flared nostrils, high arched palate, abnormal teeth, occipital flattening and large misshapen ears) 4) Skeletal anomalies (fusion of vertebrae, reduction of intervertebral spaces, spina bifida, scoliosis and kyphosis), hip deformity, and malposition of fingers and toes. 5) Congenital heart defects Its clinical significance remains unclear since approximately 90–93% of cases result in normal phenotype.

OTHER STUDIES Non-mosaic trisomy 20 is a rare trisomy and almost all affected fetuses do not survive past the first trimester of the pregnancy. Severe abnormalities are frequently present in these embryos. We report the case of prenatally diagnosed non-mosaic trisomy 20 with only minor anomalies in the fetus. At external examination of the fetus we detected only low-set ears and no other abnormalities. (Mavromatidis G, 2010)

CASE 39 Y.O NT: 0.9 (13th week) Prenatal screening shows Screen positive for Trisomy 21 (1:83) QF-PCR was done and was Normal

Karyotype : 47,XX+20

Anomaly Scan was Completely Normal !!!!!?????

We report a case of non-mosaic trisomy 20 detected prenatally by amniocentesis during the 16th week of pregnancy. Amniotic fluid cell karyotyping revealed a trisomy 20 (47,XY,+20) with 100% trisomic cells (38/38). Ultrasonographic examination did not reveal any major congenital malformations Cytogenetic analysis of blood lymphocytes from the infant revealed a normal karyotype. confined placental mosaicism with the presence of normal and abnormal cell lineages, or generalized mosaicism affecting a limited number of tissues in both the placenta and fetus. (Medeka K, 2015)

CONCLUSION According to the studies on the result non- mosaic trisomy 20 in amniotic fluid testes was reported without abnormalities in newborn and fetuses and following up from ultrasonography in 20-22 week was offer to pregnant women.

COMMENTS FOR MEDICAL GENETICIST Based on the literatures, a fetus with a full trisomy 20 shows a wide range of anomalies including: Spinal abnormalities; Cleft lip; Defect of Braine Structure; Hypotonia; IUGR; Lifelong Constipation So anomaly scan, ultrasound examination is highly recommended For excluding balanced chromosomal rearrangements the Parent karyotyping is recommended

Dr.Davood zare abdolahy Akn Dr.Ahmad ebrahimi Dr.Siamak saber Dr.Davood zare abdolahy Dr.Shirin niromanesh Fatemeh fazeli Hoda omidi

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