70.A 20-month-old boy is diagnosed with Hutchinson-Gilford progerial
syndrome (HGPS), a severe form of early-onset premature aging. He expe-
rienced normal fetal and early postnatal development, but now shows
severe failure to thrive, some lipoatrophy, bony abnormalities, a small,
beaked nose and receding mandible, hair loss, and speckled hypopigmen-
tation with some areas of tight hard skin. His neurological and cognitive
tests are normal. Genetic analysis shows a single spontaneous mutation in
codon 608 of the LMNAgene, which encodes both lamin A and lamin C.
Which of the following would you most likely expect to be directly
affected in cells obtained in a biopsy from this patient?
a. Increased heterochromatin
b. Interference with microtubule treadmilling
c. Increased synthesis of rRNA in the nucleolus
d. Loss of ability to adhere to the basement membrane through integrins
e. Aberrations in nuclear architecture
71.A newborn boy is diagnosed with Apert syndrome. He has craniosyn-
ostosis, hypoplasia of the middle part of his face with retrusion of the eyes,
and syndactyly that includes fusion of the skin, connective tissue, and
muscle of the first, middle, and ring fingers with moderate fusion of the
bones of those digits. There is very limited joint mobility past the first joint.
Which of the following were most likely decreasedin cells in the inter-digital
region of the developing hand of this newborn child?
a. Random DNA degradation
b. Inflammation
c. Cell swelling
d. bcl-2
e. DNA degradation by endonucleases
144 Anatomy, Histology, and Cell Biology