Prenatal diagnosis of familial ring 21 chromosome.

[monosomy 21]

Ring chromosome 21 is a rare chromosome anomaly often associated with mental retardation and dysmorphic features . Less commonly , the ring chromosome can be familial and associated with a normal phenotype . Phenotypically normal female carriers , however , are at increased risk of having children with Down syndrome , mosaic monosomy 21 , and variable duplication or deletion of chromosome 21 . Because of the relative mitotic and meiotic instability of ring chromosomes , abnormal cytogenetic findings encountered during prenatal diagnosis may not reflect the true genetic status of the fetus . This is a report of a phenotypically normal female carrier of a familial ring 21 chromosome . Prenatal diagnosis on her twin pregnancy revealed a mosaic 46 ,XX ,r (21 )(p 13 ;q 22 ) (77 per cent )/45 ,XX ,-21 in one fetus and a normal male karyotype in the second . The pregnancy was carried to term . Both infants are completely normal , with a non-mosaic ring 21 karyotype from the lymphocytes of one twin . The diagnostic uncertainty and problematic genetic counselling related to fetal cytogenetic abnormalities are the subjects of this report .

Diseases
Validation

Diseases presenting "however" symptom

adrenal incidentaloma

alexander disease

alpha-thalassemia

aromatase deficiency

benign recurrent intrahepatic cholestasis

cushing syndrome

dedifferentiated liposarcoma

dracunculiasis

dystrophic epidermolysis bullosa

esophageal carcinoma

focal myositis

heparin-induced thrombocytopenia

hodgkin lymphoma, classical

hydrocephalus with stenosis of the aqueduct of sylvius

junctional epidermolysis bullosa

krabbe disease

lamellar ichthyosis

megacystis-microcolon-intestinal hypoperistalsis syndrome

monosomy 21

neuralgic amyotrophy

oculocutaneous albinism

omenn syndrome

primary hyperoxaluria type 1

pyruvate dehydrogenase deficiency

sneddon syndrome

thoracic outlet syndrome

von hippel-lindau disease

wiskott-aldrich syndrome

x-linked adrenoleukodystrophy

You can validate or delete this automatically detected symptom