You have been following a 9-month-old with low muscle tone, delayed motor milestones, and failure to gain weight. Her family and gestational histories are normal except that her mother was 38 at the time of pregnancy; the child has 4 healthy siblings. The delivery was complicated by long labor and resuscitation was required, with NICU treatment for meconium aspiration. The newborn had significant hypotonia that necessitate tube feeding for a few days, but she was able to bottle-feed by the time of NICU discharge at age 7 days.
Current measurements show a length at the 10th centile for age, a weight just below the 3rd centile, and a head circumference also below the 3rd centile. You have watched her slow weight gain without prompting evaluation because it has paralleled the growth curve, and you have followed sluggish motor milestones with rolling back to front at 4 months and sitting at 8 months. She has appeared alert with good interaction and babbling.
The pictures show a slightly unusual facial appearance, with almond-shaped eyes, down-turned corners of the mouth, and bitemporal hollowing. She also has somewhat unusual genitalia with a question of hypoplastic labia that make the clitoris easily visible.
A. Initiate referral at this time, and to which subspecialty?
B. Suspect any particular diagnosis?
C. If there is a likely diagnosis, what diagnostic test would confirm it?