COVER PAGE
Address of correspondence:
1. Dr.Nalini K
Additional Professor
Department of Biochemistry
Kasturba Medical College
Manipal University, Manipal
Email: nalini.kbhat@manipal.edu
Phone no.: 0820-2922326
Authors:
2. Dr. Vijetha Shenoy Belle
Post graduate student
Department of Biochemistry
Kasturba Medical College
Manipal University, Manipal
Email: vijethashy@gmail.com
Mobile no.: 9844667820
3. Dr. Pushpa G Kini
Professor and Head
Department of Pediatrics
Kasturba Medical College
Manipal University, Manipal
4. Prince Jacob
Post graduate student
Department of Biochemistry
Kasturba Medical College
Manipal University, Manipal
5. Dr. Pragna Rao
Professor and Head
Department of Biochemistry
Kasturba Medical College
Manipal University, Manipal
DECLARATION:
I hereby declare that, this manuscript is not sent for publication/ published elsewhere.
MANUSCRIPT
NOVEL URINARY AND PLASMA BIOCHEMICAL FINDINGS IN A CHILD WITH
RECURRENT RESPIRATORY INFECTIONS
Nalini K, Vijetha Shenoy Belle, Pushpa G Kini, Prince Jacob, Pragna Rao
Abstract: Lysinuric protein intolerance is rare autsomal recessive disorder, characterized
byinability of the intestine to absorb themand increased excretion of lysine, arginine and
ornithine by kidneys. Infants with this disease do not show symptoms as long as they are
breast-fed. They develop symptoms when fed with protein rich food. This disease involves
almost all organs of the body. In this case one year old child presented with recurrent
respiratory infections and high performance liquid chromatography showed increased levels
of lysine arginine and ornithine amino acids in urine sample and consequent decreased levels
of mentioned amino acids in plasma, indicating the probable diagnosis of Lysinuric protein
intolerance. This child improved when diet is modified with low protein. Thus if a child
during the weaning period presents with failure to thrive, recurrent respiratory infections
there may be a possibility of Lysinuric protein intolerance disease.
Key words: Lysinuric protein intolerance, Failure to thrive, Respiratory infections, High
performance liquid chromatography
Introduction: Lysinuric protein intolerance (LPI) was first explained in 1965 as “protein
intolerance and defective absorption of basic amino acids”. [Gare, M. (1996) et al] The
incidence of this disease is highest in Finland (1 in 60000) and in Japan (1 in 57000) and in
India the incidence is not known. In this disease there is impairment of transport of dibasic
amino acids in the basolateral membranes of intestinal, hepatic, renal tubular cells and
characterized by protein aversions, hepatosplenomegaly, muscular weakness, osteoporosis,
sparse hair and interstitial lung disease.[ Rajantie, J, (1981) et al, Kerem E, (1993) et al]
Recurrent post prandial elevation of ammonia levels is also seen due to increased excretion of
ornithine and hence decreased utilization of urea cycle making the urea cycle defective.
[Palacín M, (2004) et al] During the past year other manifestations of this disease suggested
that it is not only a urea cycle disorder, but also a multisystem disease with uncertain
outcome. [Bröer S, (2007) et al] The aim of this case report to highlight the biochemical
aspects of identifying lysinuric protein intolerance.
Case Description:A one year old male child presented to department of Pediatrics, Kasturba
Hospital, Manipal, India, with chief complaints of failure to thrive, recurrent cough and cold,
hurried breathing, feeding difficulties and noisy breathing during sleep. The child had three
episodes of similar complaints over three months.
Family history: Non consanguineous marriage, history of two sibling deaths which was
unexplained at 2 months of age.
Immunization history:It was appropriate for age including hepatitis B and H. Influenza type
B
Physical findings: Child had sick looking, lethargic appearance. Pallor was present, no signs
of dehydration, no neurocutaneous markers and no dysmorphic features. Heart rate was
140/min, respiratory rate was 70 breaths per minute.Examination of respiratory system
revealed bilateral minimal subcostal retractions, bilateral ronchi and occasional crepitations
were heard.
Hematological findings:
Parameters
Patient’s findings
Normal range
Hemoglobin (g/dL)
7
11.2- 14.2
RBC counts (per µL)
3.14X 10 6
3.9- 5.1
MCV(fl)
69.3
72-84
MCH (pg)
22.3
25-29
MCHC (g/dL)
32.2
32-36
HCt (%)
21.7
30-38
This hematological picture is suggestive of anemia.
Biochemical investigations:
Total protein: 5.2g/dL (Reference range: 3.6-7.5 g/dL)
Plasma Ammonia: 255µg/dL (Reference range : 20-70 µg/dL)
Urine analysis showed presence of proteins and ketone bodies.
Total amino acid quantification: 180 mmoles/ g creatinine (20- 80 mmoles/g creatinine)
(DNFB method)
Arterial Blood Gas analysis:
Parameters
Patient’s findings
Normal range
pH
7.02
7.35 – 7.45
pCO2
12.9
35-48 mmHg
pO2
111
83-109 mmHg
HCO3-
3.2
22- 26 mmol/L
High Perfprmance Liquid Chromatography (HPLC) findings:
HPLC is performed on both plasma and urine samples using C-18 pre column. Plasma
sample showed decreased lysine, ornithine and arginine and urine sample showed increased
lysine, ornithine and arginine.
Table 1: Showing amino acids concentration in plasma (Units: micromoles/L)
Amino acids
Observed value
Reference value
Lysine
22.02
196±43
Ornithine
16
65±19
Arginine
0
80±24
Figure 1: Showing plasma amino acid peaks in HPLC
The arrow mark indicates that there is no peak of arginine and small peaks of lysine and
ornithine amino acid.
Table 2: Showing amino acids concentration in urine (Units: µMoles/grams of creatinine)
Amino acids
Observed value
Reference value
Lysine
6134
70-150
Ornithine
359.9
0-40
Arginine
18563
0-40
Figure 2: Showing urinary excretions of amino acids in urine
The arrow mark indicates the peaks of leucine, ornithine and lysine amino acids which were
greater than normal peaks of the mentioned amino acids.
Discussion
Lysinuric protein intolerance is mostly under diagnosed or misdiagnosed due to its highly
variable clinical presentations and undefined laboratory assessments. Thus we propose
following biochemical approach which will help in arriving at the probable diagnosis of
lysinuric protein intolerance.
In this case, plasma ammonia level was increased and total amino acid quantification of urine
sample showed higher value than the reference range for that particular age. Hematological
investigation showed anemia. HPLCrevealed increased levels of dibasic amino acids such as
lysine, arginine and ornithine in urine, and contrast decrease of the above mentioned amino
acids in plasma sample, thus favoring the diagnosis of lysinuric protein intolerance.
In LPI, decreased absorption of ornithine is observed. In the absence or low level of
ornithine, the functioning of urea cycle is hampered in liver leading to increased level of
ammonia in the plasma.[ Palacín M, (2004) et al]
Anemia which is seen in patients of LPI is due to subclinical macrophage activation and also
due to protein deprivation and deficiency of lysine. [Parto K, (1994) et al]
LPI is an autosomal recessive disease due to mutation in SLC7A7 gene ( for solute carrier
family 7, member 7).The gene mutation leads to defect in transport of dibasic amino acids
such as lysine, arginine, ornithine in renal tubules, intestine and hepatocytes, leading to
decreased absorption and excessive loss. [Ogier de Baulny H, (2012) et al] The child with
this disease is usually symptoms free while on breast feeding as breast milk contains
relatively low levels of lysine [Oyanagi K, (2001) et al] and can be usually
identifiedimmediately after weaning of child with complaints of failure to thrive, vomiting
and diarrhea. [Moosa NVA, (2005) et al]
Sinceit is multisystem disorder, patients can present with varying symptoms. Features of
lysinuric protein intolerance are thought to result from abnormal protein transport (such as
protein deposits in the lungs). [Sperandeo M. P. (2008) et al] Respiratorysystem involvement
is the most threatening complication. Lung injury could be secondary to impaired phagocytic
function and abnormal inflammatory and immune responses intrinsic to the SLC7A7 mutant
phenotype. [Mitha SV,(2014) et al]
In conclusion, failure to thrive with recurrent respiratory infection in children during their
weaning period with family history of sibling death warrants the careful evaluation of inborn
metabolic disorders. A good history, physical examination associated with plasma and urine
biochemical investigations is necessary for arriving at correct diagnosis of lysinuric protein
intolerance.
Limitations:


Other biochemical investigation which may support the diagnosis of LPI are elevated
levels of Triglycerides (TG), Lactate dehydrogenase (LDH), ferritin levels,
transaminases and orotic acid excretion in urine. The above biochemical parameters
were not measured in this patient.
Genetic analysis was not done to arrive at the definite diagnosis of lysinuric protein
intolerance.
References:

Bröer S, (2007), ‘Lysinuric protein intolerance: one gene,many problems’,
American Journal of Physiology - Cell Physiology vol. 293:C540–C541.

Gare M, (1996), ‘Lysinuric protein intolerance presenting as coma in a middle-aged
man’, Western Journal of Medicine, vol.165, October pp231–233.

Kerem E, (1993), ‘Lysinuric protein intolerance with chronic interstitial lung
disease and pulmonary cholesterol granulomas at onset’, Journal of
Pediatrics, August vol.123, pp 275–278.

Mitha SV,(2014), ‘ Lung involvement in child with lysinuric protein intolerance’
Journal of Inherited Metabolic Disease, October.

Moosa NVA, (2005), ‘Recurrent stupor due to lysinuric protein intolerance.
Neurology India’ vol 53, pp 333-334.

Ogier de Baulny H, (2012), ‘Lysinuric protein intolerance (LPI): A multiorgan
disease by far more complex than a classic urea cycle disorder’ Molecular Genetics
and Metabolism May vol.106 pp12-17

Oyanagi K, (2001), ‘Lysinuric protein intolerance and other cationic aminoacidurias’,
McGraw-Hill Medical Publication division

Palacín M, (2004), ‘Lysinuric protein intolerance: mechanisms of pathophysiology.
Molecular Genetics and Metabolism’ April vol. 81 Suppl 1:S27-37.

Parto K, (1994), ‘Pulmonary alveolar proteinosis andglomerulonephritis in lysinuric
protein intolerance: case reports and autopsy findings of four pediatric
patients’, Human Pathologyvol. 25, pp 400-407.

Rajantie, J, (1981), ‘Lysinuric protein intolerance. Basolateral transport defect in renal
tubuli’, Journal of Clinical Investigation, vol 67, April, pp 1078–1082.

Sperandeo M P, (2008), ‘Lysinuric protein intolerance: update and extended mutation
analysis of the SLC7A7 gene, Human Mutatation January vol. 29 pp 14-21.