Molecular Genetics And Gene Expression Practice Test

A 12-year-old girl has short stature, webbed neck, and widely spaced nipples. She has primary amenorrhea. Echocardiogram shows coarctation of the aorta. Karyotype analysis reveals 45,X. The clinician explains that haploinsufficiency of genes that escape X-inactivation, such as SHOX, alters transcriptional programs for skeletal growth. Which of the following is most likely disrupted in this patient?

A 2-year-old boy has profound speech delay, poor eye contact, and repetitive behaviors. He also has macrocephaly. His father had thyroid cancer in his 30s. Karyotype is 46,XY. Sequencing identifies a heterozygous pathogenic variant in PTEN. The clinician explains that PTEN normally dephosphorylates PIP3, limiting PI3K-AKT signaling and downstream transcriptional programs promoting growth and survival. Which gene expression pathway alteration explains the phenotype?