<s>[INST] context: Trisomy 13 Cleft lip, cleft palate, scalp defects suggest Trisomy 13 or Patau syndrome. Trisomy 13 and Trisomy 18 share several clinical features. The highest discriminatory values are for ectodermal scalp defects and harelip and cleft palate in trisomy 13 and elongated skull and simple arches on all digits for trisomy 18. Trisomy Most common abnormality in chromosome number (aneuploidy) is trisomy. The most common trisomy is Down's syndrome (trisomy 21). A variety of other trisomies involving chromosomes 8, 9 13, 18 and 22 have been described. Only trisomy 18 (Edwards syndrome) and trisomy 13 (Patau syndrome) are relatively common. They share several karyotopic and clinical features with trisomy 21. As in Down's syndrome an association with increased maternal age is also noted. In contrast to trisomy 21, however, the malformations are much more severe and wide ranging. As a result, only few of these infants survive beyond the first year of life, most succumb within a few weeks to months. [/INST] question: A infant with cleft lip, cleft palate, polydactly, microcephaly with holoprosencephaly, ectodermal scalp defect is suffering from: | options: A: Trisomy 21 B: Trisomy 18 C: Trisomy 13 D: Turner | answer: C </s>