Start of the story

A new born boy with Schaaf-Yang syndrome is smiling after born at 39 weeks of gestation from healthy, nonrelated parents.

A boy was born at 39 weeks of gestation to healthy, nonconsanguineous parents.
He weighed 3.3kg (13th percentile), with 50cm (15th percentile) height and 36cm (27th percentile) head circumference.

Features observed after birth

Six features observed in the boy with Schaaf-Yang syndrome at birth

Even though his weight, height, and head circumference was in the normal range, the doctor was able to observe some dysmorphic features.

First 2 months

A male newborn baby is using oxygen therapy and mechanical ventilation therapy due to recureent apnea.

During the first week, the boy started using oxygen and mechanical ventilation therapy due to recurrent apnea.

Also, his strength of sucking was weak, he had to use nasogastric-tube during the first 6 weeks of his life.

First examination

A female doctor taking closer look at the brain MRI result showing asymmetrical lateral ventricles with a mildly dysmorphic shape

He took several tests to observe the cause of his condition. Brain MRI, chromosome analysis, mitochondrial genome sequencing were performed.

The result for brain MRI showed asymmetrical lateral ventricles with a mildly dysmorphic shape, but no other abnormalities were detected. Chromosome analysis and mitochondrial genome sequencing also found no abnormalities.

End of the odyssey

12 months after birth, he was tested for a whole exome sequencing with 3billion to find the genetic cause behind his conditions.

The test found a pathogenic variant on his MAGEL2 gene which is one of an ‘imprinting’ gene.

His parents’ Sanger test results showed that the genetic variant was given from his father.

For detailed information including the inheritance pattern, please visit Rare Disease Series #9: Schaaf-Yang syndrome.


  1. ic_Disease-6
  2. Disease:
    Schaaf-Yang syndrome (MIM# 615547)
    Gene: MAGEL2


  • Hypotonia(low muscle tone)
  • Feeding difficulties
  • Delayed psychomotor development
  • Impaired intellectual development
  • Autism spectrum disorder
  • Joint contractures
  • Variable dysmorphic facial features

Visit at 38 months

A 38-month-old boy is trying to walk with the support of a rehabilitation therapist.

When he visited the hospital at 38 months, he was not able to stand without support, not speaking with any meaningful words, and showed autistic features.

His height and head circumference were below the 3rd percentile, showing that there is a developmental delay.

Currently, he is undergoing rehabilitation treatment for his developmental delays.

Stay tuned for 3billion’s next 'My Odyssey' series. We will deliver more diagnostic stories of patients diagnosed with us. Thank you.

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