Pediatric Nutrition in Practice

228 MacDonald^

Condition

Incidence

Classification

Symptoms in untreated patients

Treatment

PKU

Varies

Classic

or

severe

PKU

• 
  

Severe intellectual and neurological impairment

• 
  

Low phenylalanine diet (classic PKU, children:

between

Plasma phenylalanine

• 
  

Mousy odour

tolerate 200

-^ 500 mg daily)

populations:

concentrations >1,200 μmol/l

• 
  

Infantile spasms

• 
  

Phenylalanine-free

L-amino acid supplement

1 in 4,000 to

Moderate

PKU

• 
  

Lightly pigmented (hair, eyes and skin)

• 
  

Tyrosine supplementations (usually already

1 in 200,000

Plasma phenylalanine

• 
  

Eczema

added to

L-amino acid supplement)

concentrations >600

-^ 1,200 μmol/l

Microcephaly

• 
  

Vitamins/minerals/essential and LC PUFA

Mild

PKU

or

hyperphenylalaninaemia

• 
  

Delayed speech development

• 
  

Use of low-protein foods (special and natural)

Phenylalanine concentrations

Older

patients

to maintain ‘normal’ energy requirements

<600 μmol/l

• 
  

Hyperactivity

• 
  

Patients with mild/moderate PKU may

• 
  

Disturbed behaviour

respond to 5

-^ 20 mg/kg sapropterin daily

• 
  

Austistic features

• 
  

Self-injury

• 
  

Abnormalities of gait

• 
  

Tremor

• 
  

Grand mal seizures

MSUD

1 in 116,000

Classic MSUD

Classic

(neonatal

onset)

• 
  

Diet low in BCAA (leucine, valine, isoleucine;

Intermediate form

• 
  

Poor feeding

‘classic’ children with MSUD tolerate 400

-^ 600 mg daily)

Intermittent form

• 
  

Sweet, malty, caramel-like smell

• 
  

BCAA-free

L-amino acid supplement

Thiamin-responsive form

• 
  

Episodic vomiting

• 
  

Valine/isoleucine supplements if blood levels low

(a cofactor for BCKD complex)

• 
  

Irritability

(dosage titrated to valine/isoleucine

• 
  

Hypoglycaemia

blood concentrations)

• 
  

Lethargy

• 
  

Vitamin/minerals/essential and LC PUFA

• 
  

Encephalopathy

• 
  

Use of low-protein foods (special and natural)

• 
  

Cerebral oedema

to maintain ‘normal’ energy requirements

• 
  

Seizures

• 
  

Requires emergency regimen during illness,

• 
  

Delay in diagnosis may result in

fasting, infection or surgery

neurological damage or death

Intermediate

form

• 
  

Presents at any age (infancy to adulthood)

• 
  

Failure to thrive

• 
  

Hypotonia

• 
  

Progressive developmental delay

• 
  

Ketoacidosis

Intermittent

form

• 
  

Episodic ataxia and ketoacidosis (often withintercurrent illness or increased protein intake)

HT1

1 in 100,000

Acute or chronic form

Acute

• 
  

Diet low in tyrosine and phenylalanine

• 
  

Early infancy

• 
  

May tolerate up to 0.5 g/kg natural protein daily, but

• 
  

Severe liver failure

amount to be titrated to tyrosine/phenylalanine

• 
  

Cirrhosis

concentrations

• 
  

Hepatocellular carcinoma

• 
  

Tyrosine/phenylalanine-free amino acid supplement

• 
  

Renal Fanconi syndrome

• 
  

Phenylalanine supplements if blood levels low

• 
  

Glomerulosclerosis

(dosage titrated according to blood levels)

• 
  

Vitamin D-resistant rickets

• 
  

Use of low-protein foods (special and natural) to

• 
  

Neurological crisis

maintain ‘normal’ energy requirements

Chronic

• 
  

Vitamin/minerals/essential and LC PUFA

• 
  

Slight enlargement of liver

• 
  

Nitisinone (1 mg/kg/day)

• 
  

Mild growth retardation

• 
  

Renal tubular dysfunction and rickets

• 
  

Hepatosplenomegaly

• 
  

Liver cirrhosis

• 
  

Hepatocellular carcinoma

Table 1.

Incidence, classification and symptoms of amino acid disorders

Koletzko B, et al. (eds): Pediatric Nutrition in Practice. World Rev Nutr Diet. Basel, Karger, 2015, vol 113, pp 226–233

DOI: 10.1159/000360344