Table 2 Minimum requirements for the management and follow-up of patients with PKU
From: The complete European guidelines on phenylketonuria: diagnosis and treatment
|  | Childhood (<12 y) | Adolescence (12–18 y) | Adulthood (≥18 y) excluding maternal PKU | Maternal PKU |
|---|---|---|---|---|
Outpatient visit | Given good clinical and metabolic control: Age 0–1 years: every 2 months Age 1–12 years: twice per year Extra clinic visit as indicated | Given good clinical and metabolic control: twice per year Extra clinic visit as indicated | Given good clinical and metabolic control: once per year Extra clinic visit as indicated | Given good clinical and metabolic control: once per trimester Extra clinic visit as indicated |
Clinical nutritional assessment | Every outpatient visit: dietary assessment (3-day food record/24 h recall), anthropometric parameters (weight, height, BMI) and clinical features of micronutrient and Phe deficiency (especially anorexia, listlessness, alopecia, perineal rash) | Every outpatient visit: dietary assessment (3-day food record/24 h recall), anthropometric parameters (weight, height, BMI) and clinical features of micronutrient and Phe deficiency | Every 12–24 months: dietary assessment (3-day food record/24 h recall), anthropometric parameters (weight, height, BMI) and clinical features of micronutrient and Phe deficiency | Every outpatient visit:dietary assessment (3-day food record/24 h recall) and weight |
Metabolic control | Age 0–1 year weekly Phe Age 1–12 years fortnightly Phe Increased frequency as indicated Annually: plasma amino acids | Monthly Phe Increased frequency as indicated Annually: plasma amino acids | Monthly Phe Increased frequency as indicated Annually: plasma amino acids | Pre-conceptionally: weekly Pregnancy: twice weekly Increased frequency as indicated Pre-conceptionally: plasma amino acids |
Biochemical nutritional assessment | Annual measurement of plasma homocysteine and/or methylmalonic acid, haemoglobin, MCV and ferritin. All other micronutrients (vitamins and minerals including calcium, zinc, selenium) or hormones (parathyroid hormone) if clinically indicated | Pre-conception and at the start of pregnancy: folic acid, vitamin B12, plasma homocysteine and/or methylmalonic acid, ferritin, full blood count Pregnancy: when indicated | ||
Bone Density | BMD measurement only indicated when there are specific clinical reasons or when patients are known to be at particular risk of metabolic bone disease | The first measurement of BMD should be undertaken during late adolescence - When BMD is abnormal, DXA (with or without change of treatment) should be repeated after 1Â year. If osteoporosis (BMD < -2.5 SD) persists despite optimization of diet and physical activity, other possible causes of osteoporosis should be investigated. Treatment (including consideration of bisphosphonates) should be determined by osteoporosis severity. -Â Â If BMD results are still low but stable, yearly measurement is unnecessary. - When BMD is normal, no repeat measurement is necessary. Further study need only be considered when there are clinical reasons to do so. | BMD measurement is only indicated when there are specific clinical reasons or when patients are known to be at particular risk of metabolic bone disease | Not indicated |
Neurocognitive functions | Only neurocognitive tests when indicated. | Testing at age 12 years Proposed domains of neurocognitive testing: IQ, perception/visuospatial functioning, EF (divided into inhibitory control, working memory and cognitive flexibility) and motor control. Extra neurocognitive tests as indicated. | Testing at age 18 years Proposed domains of neurocognitive testing: IQ, perception/visuospatial functioning, EF (divided into inhibitory control, working memory and cognitive flexibility) and motor control. Extra neurocognitive tests as indicated. | Not indicated |
Adaptive issues (e.g. clinical relevant behavioural problems) | Annually: clinical assessment/discussion | Annually: clinical assessment/discussion Screening at age 12Â years | Annually: clinical assessment/discussion Screening at age 18Â years | Not indicated |
Neurological complications | If neurodegeneration occurs | If neurodegeneration occurs | Annually: clinical examination | Not indicated |
Psychosocial functioning and wellbeing and QOL | Annually: Clinical assessment/discussion Once during childhood: (PKU-)QOL questionnaire | Annually: Clinical assessment/discussion Once during adolescence: (PKU-)QOL questionnaire | Annually: Clinical assessment/discussion Once during adulthood: (PKU-)QOL questionnaire | Especially in case of not becoming pregnant, the patient may need support |
Psychiatric examination | At onset of symptoms of psychiatric disturbances | At onset of symptoms of psychiatric disturbances | At onset of symptoms of psychiatric disturbances | Not indicated |
White matter abnormalities (MRI) | When there is an unexpected clinical course and/or unexpected neurological deficits | When there is an unexpected clinical course and/or unexpected neurological deficits | When there is an unexpected clinical course and/or unexpected neurological deficits | Not indicated |
Age group specific investigations | / | / | / | Ultrasound at 18–22 weeks of pregnancy with screening for organ development (especially if there is lack of optimal metabolic control) |
| Â | Â | Â | Â | Echocardiogram in all infants who are conceived by women with either high blood Phe levels or poor maternal blood Phe control during pregnancy |