Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services for:
These symptoms do not come from long limbs themselves.
They may signal an aortic emergency, stroke, blood clot, or another serious problem, particularly in someone with a known connective-tissue or metabolic condition.
Seek urgent eye care for a sudden increase in flashes or floating spots, a dark curtain across the vision, or sudden loss of vision.
These symptoms can occur with a retinal tear or detachment and should not wait for a routine visit.
Arrange a routine appointment if you or your child has noticeably unusual body proportions, especially when there is also a family history of Marfan syndrome, aortic enlargement, unexplained early aortic surgery, or sudden death at a young age.
Routine assessment is also appropriate for new or worsening joint pain, spinal curvature, reduced movement, vision changes, or difficulty with physical activities.
Children whose proportions are changing noticeably can be assessed as part of their growth review.
Every sign above is quoted from the sofidex article on Dolichostenomelia. If you are not sure, err upward — it is always reasonable to be checked.