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Recognize the signs and symptoms of AADC deficiency

In a clinical study of 78 patients who were diagnosed with AADC deficiency, the following symptoms were documented1:

Hypotonia1

  • Most commonly reported symptom
Hyptonia reported in AADC deficiency patients
Hypotonia
n=74

Developmental delay1

  • In AADC deficiency, developmental delay may include impairments in head control, crawling, or standing, and speech delays2,3
Developmental delay reported in AADC deficiency patients
Developmental delay
n=49

Movement disorders

Oculogyric crisis1

  • Episodes of sustained upward or lateral deviation of the eyes, rhythmic orofacial movements, backward and lateral flexions of the neck, tongue protrusion, and jaw spasms4
  • Can last a few seconds or persist for several hours, and occur several times a day or week5
  • May not be present in all cases1
  • Often misdiagnosed as a seizure, epilepsy, cerebral palsy, or mitochondrial disease5,6
Oculogyric crisis
n=67

Caregivers and parents of children with AADC deficiency may have not heard of the term “oculogyric crisis” before. When describing these episodes, they may talk about observing their child suddenly4:

  • Rolling their eyes back
  • Hyperextending their head, neck, or back
  • Thrusting their tongue
  • Contracting muscles and/or twisting involuntarily

They may even describe the episodes as seizures since they may not be familiar with oculogyric crises.5,6

WATCH: Take a closer look at an oculogyric crisis episode

Other movement disorders and associated symptoms include1:

  • Dystonia (53%) n=41
  • Hypertonia (44%) n=35
  • Hypokinesia (32%) n=25

Autonomic symptoms include1:

  • Hyperhidrosis (65%) n=51
  • Hypersalivation (41%) n=32
  • Ptosis (39%) n=30
  • Nasal congestion (31%) n=24

“If all of these symptoms are observed, the diagnosis can be made. But, if you have no experience or knowledge about it, you may have difficulty making a diagnosis.”

Takanori Yamagata, MD
Department of Pediatrics, Jichi Medical University, Shimotsuke, Tochigi, Japan

Learn about common misdiagnoses and the signs to differentiate

References: 1. Brun L, Ngu LH, Keng WT, et al. Clinical and biochemical features of aromatic L-amino acid decarboxylase deficiency. Neurology. 2010;75(1):64-71. 2. Wassenberg T, Molero-Luis M, Jeltsch K, et al. Consensus guideline for the diagnosis and treatment of aromatic l-amino acid decarboxylase (AADC) deficiency. Orphanet J Rare Dis. 2017;12(1):12. doi: 10.1186/s13023-016-0522-z. 3. Hwu W-L, Chien Y-H, Lee N-C, et al. Natural history of aromatic L-amino acid decarboxylase deficiency in Taiwan. JIMD Rep. 2018;40:1-6. doi: 10.1007/8904_2017_54. 4. Hwu W-L, 
Lee N-C, Chien Y-H, et al. AADC deficiency: occurring in humans, modeled in rodents. Adv Pharmacol. 2013;68:273-284. 5. Pons R, Ford B, Chiriboga CA, et al. Aromatic L-amino acid decarboxylase deficiency: clinical features, treatment, and prognosis. Neurology. 2004;62(7):1058-1065. 6. Lee W-T. Disorders of monoamine metabolism: inherited disorders frequently misdiagnosed as epilepsy. Epilepsy Seizure. 2010;3(1):147-153. doi: 10.3805/eands.3.147.