background participants

Participant 154

On this page, you will find information about a UDN participant.

Sharing information on this website is not a requirement of UDN participation. Only descriptions about participants who give explicit consent will appear here. While these participant pages are helpful to understand our participants’ stories, they do not begin to describe their diagnostic odysseys. A special thank you goes out to our participants and their families for sharing their experiences.


Male, age 8, with global developmental day, autism, and uncoordinated walking (gait ataxia) caused by a change in the MTSS2 gene

Date of Report

Dec 11, 2019


This participant was born full-term after an uncomplicated pregnancy. He experienced some initial problems with grunting and wheezing (stridor), but he was able to go home on his second day of life.  He has had continued respiratory concerns, including weak cartilage in the walls of the larynx (laryngomalacia), aspiration, and impaired airway clearance.

As an infant, the participant had staring episodes and different movements (arm extension, back arching) that resolved. At 4 months old, he was found to have uncontrolled eye movements (nystagmus). At 8 months old, the participant was noted to have mild global developmental delay.

The participant is currently 8 years old. He has uncoordinated walking (gait ataxia). He is reading at a 2nd grade level and working on addition and subtraction.  His social skills have improved with intensive ABA therapy.  He has significant anxiety.

Symptoms / Signs
  • Global developmental delay
  • Mild intellectual Disability
  • Autism
  • Anxiety
  • Brain abnormalities (abnormal corpus callosum morphology, abnormal morphology of the hippocampus, mild cerebellar hemisphere hypoplasia)
  • Uncoordinated walking (gait ataxia)
  • Narrow forehead
  • Eye fold (epicanthus)
  • Upslanting eyes (upslanted palpebral fissures)
  • Underdevelopment of part of the retina (hypoplasia of the fovea)
  • Uncontrolled eye movements (gaze-evoked horizontal nystagmus)
  • Full cheeks
  • High, narrow palate (V-shaped)
  • Abnormality of the ears (thickened superior helices, large earlobe, underdeveloped antitragus, underdeveloped tragus)
  • Broadened eyebrows (medial flaring of the eyebrow)
  • Narrow fingertips (tapered finger)
  • Short finger
  • Inverted nipples
  • Weak cartilage in walls of larynx (laryngomalacia)
  • Weak walls in airway (tracheobronchomalacia)
  • Aspiration
  • Impaired airway clearance
  • Chronic constipation
  • Gastroesophageal reflux
  • Flow of urine from bladder to kidneys (vesicoureteral reflux)
  • Stage 1 chronic kidney disease
  • Genital abnormality (incomplete foreskin)
Current Treatments
Prior Treatments
  • Atrovent inhaler, Flovent inhaler, hypertonic saline inhaled – breathing issues
  • Cyproheptadine, Cetirizine – allergies
  • Guanifacine
  • Hyoscyamine
  • Erythromycin, Miralax, probiotic, Senna – digestive issues
  • Nexium – acid reflux
  • Trazadone
Considered treatments
Previously Considered Diagnoses
  • Angelman syndrome
  • Fragile X syndrome
  • Metabolic disorder
  • Microdeletion/duplication syndrome
  • Mitochondrial condition
  • Prader Willi syndrome
Other Photographs
Genetic Variants of Interest

In 2021, clinicians and researchers identified the following genetic change to be causing the participant’s symptoms:

Inheritance Pattern
Position (hg19)
DNA Change
Protein Change
De novo

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


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