Growth and developmental patterns in Prader-Willi syndrome.

Doctors watched 11 babies who have Prader-Willi syndrome. They wrote down when each baby sat, crawled, walked, and gained weight.

The team also checked if the genetic type mattered. They split the babies into two cytogenetic groups and compared their growth curves.

Every baby failed to thrive in the first six months. Around 10–18 months they had a short growth pause, then weight shot up while skills stayed slow.

Developmental quotient averaged about 50. Both genetic subgroups looked the same, so the pattern seems universal.

Hogg et al. (1995) extends these findings. They showed that after the rapid weight gain, older kids feel full late and weakly, so external food locks are needed.

Eisenhower et al. (2006) and Eugenia Gras et al. (2003) add that preschool and school-age kids soon show strong rituals and insistence on sameness. The combo of slow skills plus rigid routines starts in toddler years and stays.

H-Hatton et al. (2004) track the same cohort into adolescence. They link rising BMI with more tantrums and mood issues, showing the growth curve of Kennedy et al. (1993) feeds later behavior problems.

You can now predict the roadmap: poor weight gain, then early obesity, then rituals, then mood swings. Start growth charts at intake, lock food early, and build rigid routines before transitions increase. Share the timeline with parents so they expect each step and partner in prevention.