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Essential Fructosuria
It is an autosomal recessive, benign, and mostly asymptomatic metabolic disorder
caused by the deficiency or complete lack of fructokinase enzyme, leading to
increased blood levels of fructose after taking diet having sucrose or fructose and
almost 10–20% of fructose is excreted unchanged via renal excretion [21, 22].
Patients with this disorder remain unidentified for a long time and hence have a
normal life expectancy [22]. Dietary restriction of fructose is not indicated for its
treatment as it is a rare non-disease [18].
Hereditary Fructose Intolerance
This disorder is the manifestation of the deficiency of enzyme aldolase B, affecting
the liver, kidney, and small intestine, presenting with symptoms of hypoglycemia,
vomiting, nausea, lethargy, and abdominal pain and eventually coma, convulsions,
and jerks. The renal tubule is the principal target of the noxious effect of fructose
[18, 23]. Patients with this disease exhibit normal health and remain asymptomatic
unless they are not exposed to a fructose-containing diet [18]. Infants on breastfeed
develop normally with this disorder as human milk lacks fructose, whereas those on
formulas containing fructose from the first day of life do not thrive normally, lose
weight, become dehydrated and often develop hepatomegaly and most often die
within the first month of their life [22]. When a patient is suspected of hereditary
fructose intolerance, it is recommended to eliminate fructose from diet. Intensive
care and supportive therapy as fresh frozen plasma are needed in acute cases [18].
Fructose-1,6-Phosphatase Deficiency
It is not an impaired fructose metabolism, rather a disorder of gluconeogenesis, an
autosomal recessive disorder caused by a mutation in the FBPI gene. Newborns
having this disorder may present with hypoglycemia and lactic acidosis and then
maybe clinically silent [24]. In the acute cases, the symptoms may progress to irritability, coma, dyspnea, tachycardia, apneic spells, hypotonia, and hepatomegaly.
Due to impaired gluconeogenesis, glucose formation is inhibited which results in
hypoglycemia [18]. It is a very rare condition having a mortality rate of 1 in 350,000
cases [24]. Intravenous or oral administration of glucose is recommended for the
treatment of this disorder, and avoidance of fasting for maintenance therapy [18].
H. Sharif et al.
Essential Fructosuria
It is an autosomal recessive, benign, and mostly asymptomatic metabolic disorder
caused by the deficiency or complete lack of fructokinase enzyme, leading to
increased blood levels of fructose after taking diet having sucrose or fructose and
almost 10–20% of fructose is excreted unchanged via renal excretion [21, 22].
Patients with this disorder remain unidentified for a long time and hence have a
normal life expectancy [22]. Dietary restriction of fructose is not indicated for its
treatment as it is a rare non-disease [18].
Hereditary Fructose Intolerance
This disorder is the manifestation of the deficiency of enzyme aldolase B, affecting
the liver, kidney, and small intestine, presenting with symptoms of hypoglycemia,
vomiting, nausea, lethargy, and abdominal pain and eventually coma, convulsions,
and jerks. The renal tubule is the principal target of the noxious effect of fructose
[18, 23]. Patients with this disease exhibit normal health and remain asymptomatic
unless they are not exposed to a fructose-containing diet [18]. Infants on breastfeed
develop normally with this disorder as human milk lacks fructose, whereas those on
formulas containing fructose from the first day of life do not thrive normally, lose
weight, become dehydrated and often develop hepatomegaly and most often die
within the first month of their life [22]. When a patient is suspected of hereditary
fructose intolerance, it is recommended to eliminate fructose from diet. Intensive
care and supportive therapy as fresh frozen plasma are needed in acute cases [18].
Fructose-1,6-Phosphatase Deficiency
It is not an impaired fructose metabolism, rather a disorder of gluconeogenesis, an
autosomal recessive disorder caused by a mutation in the FBPI gene. Newborns
having this disorder may present with hypoglycemia and lactic acidosis and then
maybe clinically silent [24]. In the acute cases, the symptoms may progress to irritability, coma, dyspnea, tachycardia, apneic spells, hypotonia, and hepatomegaly.
Due to impaired gluconeogenesis, glucose formation is inhibited which results in
hypoglycemia [18]. It is a very rare condition having a mortality rate of 1 in 350,000
cases [24]. Intravenous or oral administration of glucose is recommended for the
treatment of this disorder, and avoidance of fasting for maintenance therapy [18].
H. Sharif et al.