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Trisomy 18 Syndrome

Trisomy 18 syndrome is characterized by microcephaly and distal arthrogryposis especially involving the hands. The position of the hands is characterized by overlapping of the third finger by the index finger and of the fourth finger by the fifth finger. The position of the hand is so characteristic that the term “trisomy 18 hand position” is commonly used to describe it. Neonates with trisomy 18 often have a prominent occiput. Chromosome studies are indicated. Ten percent of patients of neonates with trisomy 18 syndrome have translocation. Parents with balance translocations are more likely to have offspring with trisomy 18 syndrome than parents who are not carriers of the translocation.More about... 158

Trisomy 13 Syndrome
Trisomy 13 syndrome is characterized by microcephaly, holoprosencephaly, facial abnormalities ranging from hypertelorism to cyclopia, cleft palate and lip, polydactyly, narrow hyperconvex finger nails, prominent heels, and cutis aplasia in the posterior scalp. The skin lesions are very characteristic but they are not always present. Chromosomal studies are indicated to confirm the diagnosis and to detect translocations. Parents with balance translocations are more likely to have other offspring with Trisomy 13 syndrome than parents who are not carriers of the translocation.More about... 157

5p-Syndrome or Cri-du-chat Syndrome
5p-syndrome is characterized by a peculiar catlike cry. The peculiar quality of this sound is probably due to larynx and vocal cord malformations. Microcephaly, prominent epicanthal folds, and down-slanting palpebral fissures are common features. The chromosomal region involved in the larynx and vocal cord malformations is at 5p15.3. The affected chromosome in 5p-syndrome is paternal in 80% of the cases.

 

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Jones, 1997