n-truncated are deficient in the first few aa’s (7-84) – hence biologically inactive.

1-11 aa sequence is necessary for function.

Different assays:

• Intact PTH measurements: 7-84 and 1-84
• Bioactive PTH: 1-84
• CAP assay: cAMP inducible PTH. This assay determines the biologically active PTH by its ability to induce cAMP.
• PTHrP assays and PTH assays are exclusive to each other by design.

HOSP #		WARD	Neurodevelopmental clinic – Inkosi Albert Luthuli Hospital
CONSULTANT	Prof. George van der Watt	DOB/AGE	2y male

Abnormal Result

Urine organic acid analysis was performed upon which a big peak was seen, representative of phenylpyruvate.

Presenting Complaint

The patient was a 2 year old male evaluated at a neurology clinic for neurodevelopmental delay.

History

The patient’s brother died at 3 or 4 years of age with similar neurodevelopmental delay.

Examination

Unfortunately this information was unavailable. The clinician I got hold of at Inkosi Albert Luthuli hasn’t seen the patient himself.

Laboratory Investigations

Other Investigations

The urine amino acid analysis yielded a significantly raised phenylalanine: 672 umol/L (ref <67)

Final Diagnosis

This is a case of phenylketonuria

The diagnosis is also supported by a plasma phenylalanine of 672 umol/L (ref < 67).

Take Home Messages

Build-up of phenylalanine gets metabolised to phenylpyruvate (which is seen in urine at high levels).

Phenylalanine levels >600 umol/L in serum is highly indicative of phenylketonuria

Prof. George van der Watt

Biopterin cycling defects usually cause levels >125 umol/L.

This deficiency is 4-monooxygenase deficiency.

Management of PKU is with a phenylalanine restricted diet.

HOSP #		WARD	Oudtshoorn Clinic
CONSULTANT	George van der Watt & David Marais	DOB/AGE	66y Male

Abnormal Result

Presenting Complaint

Mr. X, a 66 year old male, complained of chest pain, was seen at the Oudtshoorn Emergency department and a myocardial infarction was excluded by three serial point-of-care (POC) Troponin I results.

History

• Known with hypothyroidism, but the cause was not defined yet.
• On Eltroxin 150 ug daily PO
• No other treatment.
• Various stool analyses had been sent in for culture, with no definitive result.

Examination

Unfortunately not known.

Laboratory Investigations

Free T4: 24.6 pmol/L (7.6 – 16.1 pmol/L)

Anti-Thyroglobulin Antibody levels were elevated at 1944 U/mL (ref. <115 U/mL).

Other Investigations

Later, by retrospective viewing of the patient’s results it was revealed:

Total Cholesterol (TC) was elevated at 7.6 mmol/L. Hypothyroidism is associated with hypercholesterolemia. It can be concluded by the retrospective overview of results that upon an episode of hypothyroidism, the patient had hypercholesterolemia. This was most likely due to cessation of Thyroxine treatment, to whatever reason.

Investigations also confirmatory for auto-immune hypothyroidism are:

• Anti-Thyroid peroxidase antibodies
• Anti-TSH receptor antibodies

Final Diagnosis

Auto-immune hypothyroidism

Take Home Messages

Interestingly, numerous patients with hypothyroidism is diagnosed at our Lipid Clinic at Groote Schuur Hospital. Patients are being referred for hypercholesterolaemia. Generally referral to this clinic happens when TC > 7.5 mmol/L. These patients are referred as presumed to have familial hypercholesterolaemia, but upon further work-up it is found that many of these patients have long-standing untreated hypothyroidism.

Prevalences of antithyroid antibodies as summarized by Up-to-date: