There are reports in the medical literature that a high frequency of genetic diseases
of non-hereditary origin is associated with a relatively high paternal age (45 or
over). These diseases occur as a result of fresh (new) mutations that arise in the
genes that cause structural defects, and their inheritance pattern is autosomal dominant. The defects caused by these
mutations can be diagnosed by
ultrasound scan. For example, congenital skeletal defects may be expressed
in different forms, such as very short stature (the term "dwarfism" is not used
nowadays), the most common form of which is known as achondroplasia, or bone disease associated with reduced
mineralization in the bone, resulting in bone fractures occurring while the fetus
is still in the uterus, etc. It is therefore advisable to perform an ultrasound
scan specifically to examine fetal growth.
It is important to note that "fresh" mutations can also occur in younger people,
but their frequency is lower (e.g. for very short stature, the risk is 1:10,000
or even less).
Of course, ultrasound testing cannot detect all defects, especially those causing
functional disorders of organs, but most of the severe structural anomalies can
be demonstrated.
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