background participants

Participant 105

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Male, passed away at age 2 with symptoms characteristic of You-Hoover-Fong syndrome thought to be caused by genetic changes in the TELO2 and TTI2 genes

Date of Report

Jan 25, 2019


During pregnancy, the mother of the participant developed a kidney infection that was treated with antibiotics and painkillers. Ultrasounds revealed that the participant’s legs were hyperextended at the knee, his feet were by his face, and his arms were to the side. After birth, he had trouble feeding and was found to have low blood sugar. He also had absent suck and gag reflexes and had a gastrostomy tube (G-tube) placed not long after birth to help with feeding.

The participant experienced developmental delays early on and did not visually track until 5 months of age. He also was not visually or socially responsive until 7 months when he began vocalizing. Over time he began to express feelings of hunger and responded to his parents by smiling. He had extremely limited social interaction and gave very little feedback when spoken to or played with. He was unable to speak, laugh, bear weight, walk, talk, or eat. He also had involuntary muscle movements not correlated with seizures. He passed away shortly before turning 3 years old.

Symptoms / Signs
  • Global developmental delay
  • Epilepsy
  • Brain deterioration (abnormal T2/FLAIR signal hyperintensity and volume loss in the bilateral putamen and midbrain on brain MRI)
  • Small head circumference (microcephaly)
  • Low muscle tone (neonatal hypotonia)
  • Sudden muscle jerks (myoclonus)
  • Damaged nerve cells (neuropathy)
  • Eyes turned outward (exotropia)
  • Vision impairment (cortical visual impairment)
  • High palate
  • Abnormal placement of the tongue (glossoptosis)
  • Inability to suck
  • Small jaw (micrognathia)
  • Indentation of the skin on the lower back (sacral dimple)
  • Knee hyperextension (genu recurvatum)
  • Overlapping toe
  • Curved smallest toe (clinodactyly of the 5th toe)
  • Rapid flexing of the foot (ankle clonus)
  • Rocker bottom foot (congenital vertical talus)
  • Swelling of feet (edema of the dorsum of feet)
  • Low blood sugar (neonatal hypoglycemia)
Current Treatments
Prior Treatments
  • G-tube placement
  • Physical therapy
  • Speech therapy
  • Vision therapy
  • Occupational therapy
  • Chest physiotherapy
  • Oral suction machine
Considered treatments
Previously Considered Diagnoses
  • Angelman syndrome
  • Leigh syndrome
  • Mitochondrial disease
  • Myotonic dystrophy
  • Prader-Willi syndrome
  • Spinal Muscular Atrophy
  • Temple syndrome
Other Photographs
Genetic Variants of Interest

Clinicians and researchers are investigating the following genetic changes to see if it they are causing the participant’s symptoms:

Inheritance Pattern
Position (hg19)
DNA Change
Protein Change
Autosomal recessive
Chr16: 1547476
Autosomal recessive
Chr8: 33369995

If this participant sounds like you or someone you know, please contact us!


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