What is the cause of short stature in 14.5 year old boy?

[Concernedmomofteenboy]

My 14.5 year old son has short stature (Proportionate). He's 4'8".   Unsure of cause. He eats healthy. Dr. Hasn't gotten back to me in almost 2 weeks (after calling) and I'm scared.  From what I can tell it looks like he has anemia but no clue where it's coming from.  He has a small bladder diagnosed in 2011. Can someone help, please? Thank you. If other info. is needed I can provide it.  His father and grandfather have discord lupus(skin only) and his father has NMO(Devic's-rare) and they have amer. Indian in them. His labs and xray results as follows:
FINDINGS:
Chronological age is 14 years 5 months. The standard deviation is 12 months according to the male standard.

According to the standards of Greulich and Pyle, the estimated bone age is 13 years.
Impression
Bone age is delayed by less than 2 standard deviations.

CBC:  High and low values only.
MCHC   27.6
33.7 - 35.3 g/dL L
Eosinophils 4.50 % 0.00 - 4.00 %         H
Immature Granulocytes 0.40 %
0.00 - 0.30 %         H
All other values were within normal ranges.

Comp. Metabolic Panel:
Potassium 3.5 mmol/L
3.6 - 5.5 mmol/L L

TSH, IGFBP-3, IGF-1 Somatomedin, Celiac disease AB panel and free thyroxine  were all in normal ranges.