PATHOLOGY

Detailed explanation-1: -Nondisjunction is the failure of homologous chromosomes to disjoin correctly during meiosis. This results in the production of gametes containing a greater or lesser chromosomal amount than normal ones. Consequently the individual may develop a trisomal or monosomal syndrome.

Detailed explanation-2: -Trisomy 13 is a chromosomal aneuploidy characterized by meiotic nondisjunction. The phenotypic holoprosencephaly and midline fusion aberrancies are related to a defective fusion of the prechordal mesoderm.

Detailed explanation-3: -Individuals with trisomy 13 often have heart defects, brain or spinal cord abnormalities, very small or poorly developed eyes (microphthalmia), extra fingers or toes, an opening in the lip (a cleft lip ) with or without an opening in the roof of the mouth (a cleft palate ), and weak muscle tone (hypotonia).

Detailed explanation-4: -Patau’s syndrome is a serious rare genetic disorder caused by having an additional copy of chromosome 13 in some or all of the body’s cells.