Mean Corpuscular Volume and Risk of Autism Spectrum Disorder.

Researchers looked at whether a simple blood test measuring red blood cell size (MCV) could help identify children at risk for autism. They found that mothers' blood test results didn't predict autism in their children. However, children with larger red blood cells had slightly higher chances of being diagnosed with autism. The researchers think this blood test might one day help identify at-risk children early, but more research is needed.

This exploratory study examined whether increased mean corpuscular volume (MCV), a blood test marker indicating larger red blood cells and potential vitamin B12/folate deficiency, could serve as an early biomarker for autism spectrum disorder (ASD). Researchers analyzed MCV values from 3,798 mothers and 9,633 children. While maternal MCV levels before birth showed no association with later ASD diagnosis in children, elevated MCV levels in children themselves were associated with increased ASD odds. Children with MCV values of 81-91 femtoliters showed 26-38% higher odds of ASD compared to the reference group (76 fL).

The authors suggest MCV could potentially serve as an inexpensive screening tool to identify at-risk children.

MCV testing is inexpensive and routinely available, making it potentially valuable for early screening. However, the modest effect sizes and exploratory nature require validation in larger, well-designed studies before clinical implementation. Further research needed to establish clinical utility.

This is an exploratory study with unclear methodology details. Sample selection criteria, study design, and statistical approach are not well described. The clinical significance of the modest odds ratios and potential confounding factors are not addressed.

Autism spectrum disorder (ASD) can be diagnosed as early as 18 months old, but more reliably after two years. Notably, no laboratory test exists to identify mothers at higher risk of having a child who will later be diagnosed with ASD or to identify at-risk infants before the manifestation of symptoms. One frequently described risk factor for neurodevelopmental disorders is vitamin B12 and folate deficiency, which results in macrocytic anemias. We evaluated whether increased mean corpuscular volume (MCV), an indicator of macrocytic anemias in the mother or child, is associated with increased odds of a subsequent ASD diagnosis.

Maternal mean MCV (mMCV) was calculated from any value in the year before birth, and the mMCV for the child was calculated from any MCV value from birth until the end of the follow-up time. Odds ratios with 95% confidence intervals were estimated from logistic regression models. A total of 3798 mothers (984 cases-ASD/2814 controls) and 9633 children (3206 cases-ASD/6427 controls) had at least one MCV value. The mMCV for the mother one year before birth was not associated with a later diagnosis of ASD in their children.

In children, compared to the reference group (mMCV 76 femtoliters (fL)), an mMCV of 81 fL, 84 fL, and 91 fL was increased odds of ASD of 26%, 38%, and 32%, respectively. The MCV can be a potential inexpensive biomarker to identify a subset of children at risk of ASD or other developmental disorders; this exploratory study can inform larger studies to determine the clinical utility of MCV.