Indications for chromosome analysis in clinical genetics

Chromosomal analysis

 * prenatal
 * postnatal

Indications for prenatal analysis of chromosomes

 * advanced maternal age
 * higher than 35 ys in the date of delivery (increased risk of chromosomal aneuploidies, namely M. Down)
 * positive screening of congenital anomalies (1st or 2nd trimester maternal serum screening test + increased NT - higher risk of chromosomal abnormalities)
 * positive family history
 * affected child/fetus in previous pregnancy (with chromosomal abnormality)
 * parent - carrier of balanced chromosomal aberration (e.g. translocation)
 * patological or atypical ultrasound finding (IUGR – intrauterine growth retardation, microcephaly, hyperechogenic bowel, hydronephrosis, Fallot tetralogy, club foot, polyhydramnios/oligohydramnios, hygroma colli cysticum,...)
 * important for differential diagnosis (ultrasound finding could be solitary – usually without chromosomal abnormality or syndromologic – in many cases caused by chromosomal abnormality)
 * others (e.g. mother after chemotherapy, in vitro fertilisation pregnancy, …)

Indications for postnatal analysis of chromosomes

 * 1) children:
 * 2) * craniofacial dysmorphy (flat occiput, epicantus, hypertelorism, cleft lip, cleft palate, malformed ears, craniosynostosis, macroglossia,...)
 * 3) *congenital anomalies (heart defects, cryptorchism, NTD – neural tube defects, urogenital defects, agenesis corpus callosum,...)
 * 4) *psychomotoric retardation
 * 5) *developmental delay, failure to thrive
 * 6) *growth retardation, short stature
 * 7) *hypotonia
 * 8) puberty:
 * 9) *amenorhoea
 * 10) *gynecomastia
 * 11) *developmental defects of secondary sexual features
 * 12) adults:
 * 13) *infertility/sterility
 * 14) *recurrent spontaneous abortions
 * 15) *abnormal spermiogram in men
 * 16) *positive family history (reproduction loss, affected child, chromosomal aberration in relatives,…)
 * 17) *gamete donors