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Patient stories: children diagnosed with AADC deficiency

Following are four illustrative examples of children and their journeys leading to a diagnosis of aromatic L-amino acid decarboxylase (AADC) deficiency.*

Of course, every child is different, so each child’s journey can be different.

Choose a child to read about:

Meet ‘Anna’, a baby girl with muscle spasms and delays in development

Not a real patient. Hypothetical profile based on actual patient experiences.

Anna had difficulty feeding as a newborn

  • Anna was a newborn when her parents first noticed that she had problems feeding. Her difficulty with breastfeeding led to bottle feeding, with high-flow nipples for her bottles to ensure she was getting enough nutrition
  • Anna coughed and turned red as if she was having trouble breathing while taking the bottle

Anna could not do what other babies her age could do

  • As Anna grew, her parents noticed other problems. For example, at around 9 months old, she couldn’t hold her head up, and didn’t roll over
  • Anna also drooled constantly and often had a runny nose

Anna started to have episodes where her eyes would move involuntarily

  • Anna’s eyes would suddenly swing upward and would stay there for several minutes and sometimes much longer
  • During these episodes, called ‘oculogyric crises’, Anna would seem frozen or zoned out
  • These episodes seemed similar to seizures, so Anna’s parents spoke with her doctor about it, who ran tests and ruled out seizure disorders

Anna was referred to a paediatric neurologist

  • Anna’s paediatric neurologist ordered routine blood work. The results came back normal
  • The doctor then ordered a magnetic resonance imaging (MRI) scan, which was also normal

Anna underwent special testing of her cerebrospinal fluid (CSF)

  • This test was done by collecting some of Anna’s spinal fluid using a procedure called a lumbar puncture
  • This test measured the level of certain natural chemicals in the fluid surrounding Anna’s brain
The results of the CSF analysis showed that Anna had AADC deficiency

Introducing ‘James’, a teenage boy with unexplained muscle spasms

Not a real patient. Hypothetical profile based on actual patient experiences.

James had trouble feeding and eating

  • As a newborn, James had trouble feeding. His parents cut a hole in the nipples of his bottles to help him feed

James had difficulties that other children his age did not

  • James took a long time to fall asleep, and would wake up multiple times during the night
  • James was very sensitive to temperature, and would sometimes sweat even if it wasn’t warm
  • Throughout his childhood, James never met the typical milestones that most children meet. He couldn’t hold his head up, sit, crawl, stand, or walk without help, and he was never able to speak

James could not always control his movements

  • Sometimes, James would make random motions and his arms and legs would twist uncontrollably
  • James’ parents thought these spells looked like seizures

James was diagnosed with cerebral palsy and given medication, but his symptoms did not improve

  • At 6 months old, James was diagnosed with cerebral palsy
  • James received some medications for his abnormal movements, but they made his symptoms worse

James’ parents took him to other doctors for more testing

  • James’ doctors ordered imaging tests for his brain, which were normal
  • The doctor also ordered common blood and urine tests to assess James’ organs and metabolism, and these tests came back normal

At 17 years old, James’ parents decided to take him to another paediatric neurologist who ordered a cerebrospinal fluid (CSF) analysis

  • For this test, some of James’ spinal fluid was collected in a procedure called a lumbar puncture, or a spinal tap
The results of the CSF analysis helped his doctors reach a diagnosis of AADC deficiency

Meet ‘Louis’, a male toddler with irritability, floppiness, and rigid muscles

Not a real patient. Hypothetical profile based on actual patient experiences.

Parents notice a range of signs and symptoms

  • Parents noticed that, at around 4 months of age, Louis was floppy with little muscle tone, had very little spontaneous movements, was underweight for his age, and had some irritability

Referred to a paediatric neurologist

  • Between 6–12 months, after having spasms that looked like epilepsy, his parents took him to hospital multiple times.
    The paediatric neurologist:
    • Ordered brain scans, which came back normal
    • Prescribed medication for epilepsy
  • He was then seen by a developmental paediatrician

Spasms are diagnosed as dystonia

  • A paediatric neurologist examined him and documented:
    • Inability to sit without help or grasp objects
    • Floppy limbs
    • Trouble swallowing, regular vomiting, and constipation
    • Excessive drooling and sweating
    • Disturbed sleep
  • Additional brain scans were ordered and came back normal
  • A new paediatric neurologist reclassified the spasms thought to be epilepsy as dystonic movement, which is a movement disorder where muscles contract involuntarily, causing repetitive or twisting movements
  • He was referred to:
    • Movement disorder specialist
    • Gastroenterologist
    • Physical therapist
    • Occupational therapist

Louis is examined for a neurotransmitter disorder

  • After considering a diagnosis of mitochondrial disease, he was evaluated for a neurotransmitter disorder

Diagnosed at 2 years of age

  • The paediatric neurologist ordered
    • A blood test for plasma AADC enzyme activity, which is reduced in patients with AADC deficiency
    • A cerebrospinal fluid metabolite panel, which measures the levels of different compounds (metabolites) involved in the making of neurotransmitters by collecting some of the fluid in the spine
  • The results of these tests helped the paediatric neurologist diagnose him with AADC deficiency
The results of the CSF analysis helped his doctors reach a diagnosis of AADC deficiency

Meet ‘Sofia’, a female toddler with involuntary eye movements, developmental delays, and a previous diagnosis of cerebral palsy

Not a real patient. Hypothetical profile based on actual patient experiences.

Seen by a paediatrician

  • At 3 months of age, the paediatrician noted that she couldn’t lift her head and had low muscle tone, or ‘floppiness’, known as hypotonia

Sofia had episodes where her eyes moved uncontrollably

  • By 5 months of age, she began experiencing severe, involuntary spasms, known as ‘oculogyric crises’, which affected her eyes

Paediatric neurologist considers diagnosing her with cerebral palsy

  • These episodes led to a referral to a paediatric neurologist, who considered diagnosing her with cerebral palsy

No developmental milestones achieved

  • Sofia remained inactive and experienced severe insomnia, in addition to not achieving developmental milestones, which led to a referral to another paediatric neurologist
  • New paediatric neurologist conducted brain scans, which came back normal
  • Sofia began seeing a developmental pediatrician

Genetic testing is recommended

  • By 14 months of age, after there was no improvement in her condition and doctors could not make a definitive diagnosis, she was referred to a specialised centre for genetic testing

Diagnosed at 15 months: Genetic test confirms Sofia has AADC deficiency

  • The genetic test confirmed an alteration, or mutation, in the DDC gene
  • A blood test for plasma AADC enzyme activity, which is reduced in patients with AADC deficiency, also shows a reduced amount of the enzyme in her blood
The results of the genetic test helped her doctors reach a diagnosis of AADC deficiency

*Not a real patient. Hypothetical profile based on actual patient experiences.
Consensus guidelines recommend confirming an AADC deficiency diagnosis with a genetic test.

GL-AADC-0987 | March 2023

Welcome to About AADC

A website for parents and caregivers of children with AADC deficiency, and members of the public interested in the condition. This website has been provided by PTC Therapeutics.

This educational website provides information to support awareness of a rare neurotransmitter disorder called aromatic L-amino acid decarboxylase (AADC) deficiency.