The symptoms of homocystinuria vary in timing and severity, which makes early detection difficult. Some babies show signs soon after birth. Others remain symptom-free until childhood or adolescence. Because the symptoms affect the eyes, bones, brain, blood vessels, and connective tissue, this disorder is often mistaken for other conditions. Recognising the symptoms of homocystinuria early is vital for fast diagnosis and treatment.
Developmental Delays and Growth Issues
One of the first signs is developmental delay. Babies may take longer to sit, crawl, or walk. Speech and learning skills can also be slow to develop. These issues often become clear when children are compared with peers. However, some children, especially those with mild forms, may develop normally in the early years.
Eye Problems – A Key Feature
The eyes are often affected. Many patients develop ectopia lentis, where the lens of the eye slips out of place. This usually happens before age 10. It can cause severe nearsightedness, distorted vision, or astigmatism. If untreated, it may lead to glaucoma or retinal detachment. Any child with lens dislocation should be tested for homocystinuria.
Skeletal Changes Over Time
Skeletal issues are another common symptom. People with this condition often have long limbs and fingers, giving a Marfan-like appearance. Other problems include scoliosis, sunken chest, and weak bones. Osteoporosis can even appear in childhood. These signs become more visible during puberty rather than in infancy.
Brain and Behavioural Symptoms
The brain and nervous system can also be affected. Some children have seizures, learning difficulties, or behavioural problems. Intelligence can range from normal to mild intellectual disability. Older children and adults may experience anxiety or depression.
Blood Clot Risks – A Serious Concern
One of the most dangerous symptoms of homocystinuria is blood clotting. High homocysteine makes blood more likely to clot. This can lead to deep vein thrombosis, pulmonary embolism, stroke, or heart attack—even in young people. Any child or adult with an unexplained clot should be checked for this disorder.
Additional Signs and Rare Forms
Some patients have pale hair and skin because of altered methionine metabolism. This feature can raise suspicion in certain populations. Digestive symptoms like vomiting, poor feeding, or slow growth can occur in infancy. Rare forms of homocystinuria, especially those linked to vitamin B12 defects, can appear soon after birth with symptoms such as weakness, poor feeding, or even coma. These cases need urgent care.
Variable Presentation and Screening
Not every patient shows the same symptoms. Some respond well to vitamin B6 and have milder signs. For these patients, diagnosis often happens by chance or during family screening. Newborn screening can detect many cases by checking methionine levels. However, some cases are missed, especially in non-CBS types.
Summary
The symptoms of homocystinuria affect many body systems and develop slowly. Because they look like other conditions, diagnosis can be delayed. But with early detection and treatment, many problems can be avoided, giving patients a better chance at a healthy life.
