Chromosome Disorders

Aberrations in chromosomes

Result from loss, gain, or abnormal arrangement of chromosomes or chromosomal material; excess/deficiency of genetic material

Ploidy

The number of complete homologous sets of chromosomes in a gene

Anauploidy

Different number of chromosomes; loss OR gain of a chromosome

What does autosomal aneuploidy lead to

Birth defects and mental repatriation

Sex aneuploidy can lead to

Sexual infantilism and mild retardation

Trisomy

3 of a chromosome

Monosomy

1 of a chromosome

What happens in Down syndrome

Extra chromosome at position 21

Clinical feature of Down syndrome

Hypotonia

Mental retardation

Short stature

Prematurity

Flat nasal bridge

Simian crease

What is the characteristic of Klinefelter’s syndrome

Extra X chromosome

What happens in Turner’s syndrome

One x (monosomy)

Deletion

Breakage or loss of a portion of a chromosome

Deletion in renal oncocytoma

Deletion of terminal end of chromosome 1p (monosome of chromosome 14) in renal oncocytoma

Deletion in Cri-du-Chat

Deletion of part of the p arm of chromosome 5 (profound retardation, voice of crying cat, physical issues)

Translocations

Breakage of two chromosomes with transfer of one broken segment to another chromsome

Translocation in CML

Bone marrow disease characterized by increased proliferation of a WBC line and responsible for 20% of adult leukemia

Isochrome formation

Breaking of chromosome at centromere, one arm being duplicated resulting in chromosome with two p’s or two ‘s

Another name for Down syndrome

Trisomy 21

Another name for Turner’s syndrome

Monosomy x

Disease of isochrome formation

Angel man

Ring chromosome

Deleted genetic material at ends of chromsome and fusion to form a ring

Paracentric inversion

Break in chromosome and inversion of that piece before being reinserted

Diceentric chromosome

When two chromosomes are broken, two parts join and the rest are deleted

Pericentric inversion

Break around the centromere and inversion before reinsertion