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Participant 137

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Male, age 7 with global developmental delay, hearing loss, gastrointestinal abnormalities, and absent saliva flow (xerostomia) caused by a change in the SLC12A2 gene

Date of Report

Jul 17, 2019


The participant was delivered early at 31 weeks by emergency cesarean section (C-section) due to maternal preeclampsia. He spent the next eight weeks in the hospital due to feeding and breathing problems. At that time, he was diagnosed with profound bilateral hearing loss and had ear tubes (tympanostomy and pressure equalization tubes) placed. He also had a right cochlear implant placed at 13 months of age and a left cochlear implant placed at 24 months.

Since birth, the participant has had low muscle tone (hypotonia) and was evaluated by developmental specialists at 6 months old. He was found to have motor and developmental delay with poor head control and absent reflexes in his legs.

The participant was found at 10 months to have thick oral secretions and persistent coughing, which caused breathing obstruction at 16 months. He also has gastrointestinal problems, including acid (gastroesophageal) reflux and constipation. A gastrotomy tube (G-tube) was placed at 18 months to help with weight gain.

Symptoms / Signs
  • Profound global developmental delay
  • Absent saliva flow (xerostomia)
  • Gastrointestinal abnormalities (gastroesophageal reflux, gastroparesis, constipation, intermittent diarrhea, midgut malrotation, hiatus hernia)
  • Hearing loss (sensorineural hearing impairment, high-frequency hearing impairment)
  • Abnormal sweat production (abnormal sweat homeostasis)
  • Failure to thrive
  • Abnormalities of the central nervous system (EEG with focal slow activity, generalized hyperreflexia, abnormal auditory evoked potentials, abnormal sudomotor regulation)
  • Head shape abnormalities (microcephaly, dolichocephaly, broad forehead, narrow forehead, frontal bossing)
  • Poor head control
  • Differences in facial features (midface retrusion, epicanthus, hypoplasia of the ear cartilage)
  • Teeth grinding (bruxism)
  • Breathing issues (choanal atresia, upper airway obstruction)
  • Inflammation of the esophagus (esophagitis)
  • Nail abnormalities (fragile nails, ridged fingernail)
  • Thickening of palms and soles (palmoplantar keratoderma)
  • Abnormal palm and foot creases (multiple palmar creases, multiple plantar creases)
  • Heart abnormalities (patent ductus arteriosus, right ventricular dilation, tricuspid regurgitation)
  • Protruding sternum (pectus carinatum)
  • Curved spine (thoracic kyphosis)
  • EMG abnormality
  • Severe low muscle tone (muscular hypotonia)
  • Partial dislocation of hip (hip subluxation)
  • Accumulation of fat in the liver (hepatic steatosis)
  • Gallstones (cholelithiasis)
  • Dilatation of the renal pelvis
  • Inability to walk
  • Reduced function of reflexes in lower limbs (hyporeflexia)
  • Abnormality of foot reflex (Babinski sign)
  • Fusion of 2nd and 3rd toes (2-3 toe syndactyly)
  • Joints move beyond normal range (joint hypermobility)
  • Bone abnormalities (osteopenia, slender long bone, shallow acetabular fossae)
  • Oral aversion
  • Heat intolerance
  • Elevated levels of creatine phosphokinase in blood (elevated serum creatine kinase)
  • Abnormality of amino acid metabolism
Current Treatments
  • Albuterol – airway obstruction
  • Biotene – xerostomia
  • Miralax – constipation
  • Mucomyst – asthma
  • Physical therapy
  • Prevacid – gastroesophageal reflux disease
  • Occupational therapy
Prior Treatments
Considered treatments
Previously Considered Diagnoses
  • Cerebral folate deficiency
  • CHARGE syndrome
  • Cystic fibrosis
  • Lysosomal storage disorder
  • Mitochondrial disorder
  • Spinal muscular atrophy
Other Photographs
Genetic Variants of Interest

Clinicians and researchers have identified the following genetic change to be causing the participant’s symptoms (Macnamara et al. 2019). The site is looking for other individuals with heterozygous, compound heterozygous or homozygous variants in this gene.

Inheritance Pattern
Position (hg19)
DNA Change
Protein Change
Autosomal recessive

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


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