Infant with failure to thrive and hypotonia
The patient in this case exhibited all the major criteria for a diagnosis of Prader-Willi syndrome: FTT with feeding difficulty, developmental delay, dolichocephaly, hypotonia, and hypogonadism. On swallow study, she was found to have feeding difficulties, specifically pharyngoesophageal dysphagia. The Southern blot analysis revealed a single methylated band of maternally derived DNA and the absence of paternally derived material. This restriction pattern was consistent with the diagnosis of PWS.
Because of the patient’s feeding difficulty, a nasogastric tube (NG) was placed. She was discharged home after 6 days and was referred to an academic center with a PWS clinic. Regular visits to her pediatrician for weight checks were recommended. Outpatient physical and occupational therapy were started with the goal of improving her strength and developmental milestones. Because of her abnormal swallow study, speech therapy was also ordered.
At her 6-month well-child checkup, the patient weighs 5.5 kg, still less than the 3rd percentile, and tolerates NG feeds well. The mother is going to start solid feeds as tolerated with management from speech therapy. The NG tube will remain in place for supplementation until feeding by mouth is completely tolerated and the infant shows consistent, appropriate weight gain.
Infants who fail to regain their birthweight by 2 weeks of age are concerning. This case underscores the importance of reviewing growth curves at every single clinic visit. When both FTT and hypotonia are present, further investigation is warranted. A careful history, including a detailed evaluation of social factors and feeding habits, a thorough physical examination, a review of the newborn’s state screening results, and additional tests as needed can help differentiate between acquired and congenital disorders.
Because both AS and PWS have unique features that only present later in childhood, clinicians need to be able to recognize nonspecific clues such as FTT, hypotonia, and developmental delay. Early diagnosis allows prompt medical intervention and enables parents to obtain helpful education and support.
1. Bergman P, Graham J. An approach to “failure to thrive.” Aust Fam Physician. 2005;34(9):725-729.
2. Jeong SJ. Nutritional approach to failure to thrive. Korean J Pediatr. 2011;54(7):277-281.
3. Cole C, Binney G, Casey P, et al. Criteria for determining disability in infants and children: low birth weight. Evid Rep Technol Assess (Summ). 2002;(70):1-7.
4. CarneiroâSampaio M, Jacob CM, Leone CR. A proposal of warning signs for primary immunodeficiencies in the first year of life. Pediatr Allergy Immunol. 2011;22(3):345-346.
5. Wright CM. Identification and management of failure to thrive: a community perspective. Arch Dis Child. 2000;82(1):5-9.
6. Schwartz ID. Failure to thrive: an old nemesis in the new millennium. Pediatr Rev. 2000;21(8):257-264.
7. Leyenaar J, Camfield P, Camfield, C. A schematic approach to hypotonia in infancy. Paediatr Child Health. 2005;10(7),397-400.
8. Hall BD, Smith DW. Prader-Willi syndrome. A resumé of 32 cases including an instance of affected first cousins, one of whom is of normal stature and intelligence. J Pediatr. 1972;81(2):286-293.
9. Williams CA, Beaudet AL, Clayton-Smith J, et al. Angelman syndrome 2005: updated consensus for diagnostic criteria. Am J Med Genet A. 2006;140(5):413-418.
10. Williams CA, Zori RT, Hendrickson J, et al. Angelman syndrome. Curr Probl Pediatr. 1995;25(7):216-231.
11. Holm VA, Cassidy SB, Butler MG, et al. Prader-Willi syndrome: consensus diagnostic criteria. Pediatrics. 1993:91(2):398-402.
12. Zellweger H, Schneider HJ. Syndrome of hypotonia-hypomentia-hypogonadism-obesity (HHHO) or Prader-Willi syndrome. Am J Dis Child. 1968;115(5):588-598.
13. Cassidy SB, Schwartz S, Miller JL, Driscoll DJ. Prader-Willi syndrome. Genet Med. 2012;14(1):10-26.
14. Bigi N, Faure JM, Coubes C, et al. Prader-Willi syndrome: is there a recognizable fetal phenotype? Prenat Diagn. 2008;28(9):796-799.
15. Butler MG, Manzardo AM, Forster JL. Prader-Willi syndrome: clinical genetics and diagnostic aspects with treatment approaches. Curr Pediatr Rev. 2016;12(2):136-166.