This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Growth and development, Subject name: Pediatrics
Which of the following is true about Constitutional Delay in growth? 
Select and explain. 
A. Neonates with constitutional delay show anomalies at bih, B. IGF-1 levels are low for chronological age, C. Bone age is normal, D. IGF-1 levels are low for bone age
B: IGF-1 levels are low for chronological age
Answer: B: IGF-1 levels are low for chronological age 
Explanation: Constitutional growth delay is a physiological variant of sho stature. Here children grow normally upto 6-12 months of life. Thereafter, there is deceleration such that the height and weight fall below the 3rd centile. By 3 yrs of age,normal height velocity is resumed and continues to grow below and parallel to the 3rd centile. Here pubey is delayed; And the bone age is consistent with the child&;s height age, but lower than the chronological age by 2-3 yrs , unlike in the familial sho stature. Hence IGF-1 produced is low for the chronological age but consistent with the bone age that corresponds to the height age. Ref. OP.Ghai ,9th edition, chapter 2