Galactosemia is a genetic disorder characterized by the inability to properly metabolize the sugar galactose, leading to its accumulation in the blood. It is caused by a deficiency of the enzyme galactose-1-phosphate uridyl transferase and exhibits various symptoms and complications, including cognitive and developmental issues. Treatment involves strict galactose restriction through medical nutrition therapy to manage the disorder's effects and prevent complications.

1. GALACTOSEMIA
KAUSHIKI R
I MSC CLINICAL NUTRITION AND DIETETICS
ROLL NO.: 20MCN016

2. LESSON OUTCOMES
At the end of this session, one should know about:-
 What is Galactosemia and its Pathophysiology
 Different types of Galactosemia
 Causes, Signs and Symptoms, and Complications
 Medical Therapy
 Medical Nutrition Therapy

3. CONTENT
 Introduction
 Pathophysiology
 Cause of Galactosemia
 Signs and Symptoms
 Complications
 Diagnosis
 Types of Galactosemia
 Medical Therapy
 Medical Nutrition Therapy
 Nutrition Education and Counselling

4. GENETIC METABOLIC DISORDERS
 Genetic metabolic disorders are inherited traits that result in the
absence or reduced activity of a specific enzyme or cofactor necessary for
optimal metabolism.
 Inherited as autosomal-recessive traits.
 Can be treated through Medical Nutrition Therapy.
 Steps involve in treatment are:
- restricting the amount of substrate available
- supplementing the amount of product
- supplementing the enzymatic cofactor
- combining any or all of these approaches

5. CARBOHYDRATE METABOLISM DISORDERS
 A group of metabolic disorders that occur when the carbohydrates are not
broken down due to inadequate or lack of enzymes required for the
metabolic processes.
 Inherited.
 New born babies get screened for the disorders.

6. INTRODUCTION
 Galactose is a naturally occurring sugar present in human organs.
 It forms a part of lactose, a main sugar present in animal milks.
 Lactose is broken down into glucose and galactose by the enzyme lactase.
 When galactose is not metabolized by the body, it results in
GALACTOSEMIA.

7. GALACTOSEMIA
“Galactosemia is a genetic disorder that affects the ability of the human
body to metabolize the sugar, galactose properly.”
 Galactosemia implies galactose in the blood due to the fact that the
body cannot breakdown galactose and retains high levels of galactose
in the blood.

8. PATHOPHYSIOLOGY
 Galactosemia results from a disturbance in the conversion of galactose to
glucose because of the absence or inactivity of one of the enzymes.
 The enzyme deficiency causes an accumulation of galactose, or galactose
and galactose-1-phosphate, in body tissues.
 In addition, expanded newborn screening programs have identified many
newborns with Duarte galactosemia.
 These infants have one allele for galactosemia and one for Duarte
galactosemia and are often said to have “D/G galactosemia.”
 The Duarte allele produces approximately 5% to 20% of the GALT enzyme.
 Little is known about the natural history of D/G galactosemia; apparently
infants and children develop normally without medical complications.

9. SCHEMATIC DIAGRAM OF THE METABOLISM OF
GALACTOSE IN GALACTOSEMIA
Image Source: Kathleen Mahan L., Janice L. Raymond, Krause’s Food and Nutrition Care
Process, 14th Edition, Elsevier, Page 905
Absence of the enzyme
Galactose-1-phosphate
uridyl transferase blocks the
breakdown of galactose to
glucose which causes in the
accumulation of galactose in
the blood.
This results in Galactosemia.

10. GENERAL CAUSE
 Caused due to the missing or lack of
function of GALACTOSE-1-
PHOSPHATE URIDYL TRANSFERASE
(GALT).
 This hereditary condition is passed
from parent to child as an autosomal
recessive disease.

11. SIGNS AND SYMPTOMS
At Early Stages
 A baby may develop signs of galactosemia within the first few days of life if the
consume lactose found in breast milk or baby formula.
 These initial signs include:
• Refusal to eat
• Spitting up or vomiting
• Yellowing of the skin (jaundice) Lethargy
• Cataracts
At Later Stages
Individuals affected with Galactosemia tend to have:
 Learning disabilities
 Neurological impairments
 Ovarian failure

12. COMPLICATIONS
 Cognitive development
 Speech and language
 Neurological complications
 Psychosocial development
 Endocrinology / Fertility
 Bone health
 Cataract

13. DIAGNOSIS
 Classic galactosemia and clinical variant galactosemia are diagnosed when
galactose-1-phosphate is elevated in red blood cells and GALT enzyme
activity is reduced.
 Molecular genetic testing is also available to identify mutations in
the GALT gene.
 New born Screening

14. TYPES OF GALACTOSEMIA
Three main types of galactosemia – based on genetic causes, signs and
symptoms, and severity
 Classic Galactosemia (type 1)
 Galactokinase deficiency (type 2)
 Galactose epimerase deficiency (type 3)
Variant of Classic Galactosemia (type 1) – Duarte Variant Galactosemia

15. CLASSIC GALACTOSEMIA (TYPE 1)
 The most common and severe type
 Caused by mutations in the GALT gene
 Characterized by a complete deficiency of an enzyme called galactose-1-
phosphate uridyl transferase (GALT)
 Early signs and symptoms - liver dysfunction, susceptibility to infections,
failure to thrive, and cataracts.
 Complications - intellectual deficits, movement disorders, and premature
ovarian failure (in females).
 These can usually be prevented or improved by early diagnosis and
treatment, but other progressive or long-term problems are common
despite treatment.

16. GALACTOKINASE DEFICIENCY (TYPE 2)
 Caused by mutations in the GALK1 gene.
 Characterized by a deficiency of the enzyme galactokinase 1.
 Normally causes only the development of cataracts.
 Rarely causes pseudotumor cerebri.

17. GALACTOSE EPIMERASE DEFICIENCY (TYPE 3)
 Caused by mutations in the GALE gene
 Characterized by a deficiency of the enzyme UDP-galactose-4-epimerase.
 Symptoms and severity of this type depend on whether the deficiency is
confined to certain types of blood cells or is present in all tissues.
 Some people with this type have no signs or symptoms
 Others have symptoms similar to those with classic galactosemia.
 Like in classic galactosemia, many symptoms can be prevented or
improved with treatment.

18. DUARTE VARIANT GALACTOSEMIA
 A "variant" of classic galactosemia
 A person has mutations in the GALT gene but has only partial deficiency of
the enzyme.
 Infants may have jaundice, which resolves when switched to a low-
galactose formula.
 Some studies have found that people with this form are at increased risk
for mild neurodevelopmental problems, but other studies have found
there is no increased risk.
 The risk may depend on the extent of the deficiency.

19. MEDICAL TREATMENT
 When diagnosis and therapy are delayed, intellectual disability can result
(Waisbren, 2006).
 With early diagnosis and treatment, physical and motor development
should proceed normally.
 However, intellectual achievement may be depressed.
 Patients often have IQs of 85 to 100, visual-perceptual and speech
difficulties, and problems with executive function (Doyle et al, 2010;
Kaufman et al, 1995).
 Ovarian failure affects approximately 75% to 95% of women with
galactosemia (Forges et al, 2006).

20. MEDICAL NUTRITION THERAPY
 Galactosemia is treated with lifelong galactose restriction.
 Galactose restriction mandates strict avoidance of all milk and milk
products and lactose containing foods.
 Effective galactose restriction requires careful reading of food product
labels.
 Infants with galactosemia are fed soy-based formula.

21. MEDICAL NUTRITION THERAPY (CONTD.)
 All fruits and vegetables can be consumed with galactose content <25
mg/100 g.
 Many centers eliminate galactose from the diets of these children for the
first year of life; other centers do not.
 Maintaining a galactose-restricted diet is not harmful as long as
alternative sources of those nutrients abundant in dairy foods, such as
calcium and vitamins A and D, are provided.
 Calcium and vitamin D supplementation is often required by children and
adults with galactosemia.
 Energy, protein, vitamin, and mineral needs are similar to those of other
individuals unaffected by this disease.

22. Allowable Foods Foods to be Avoided
(Galactose containing foods)
• Cooked and dry cereals (cooked
without milk or unsafe ingredients)
• All fruits and vegetables except for
those that are processed with unsafe
ingredients
• Meat, fish, poultry, eggs, nuts
• Milk and milk substitutes like Similac,
Isomil, Enfamil, Prosobee, Gerber, Good
start, Soy Plus
• All forms of animal milk
• Imitation or filled milk
• Cream, butter, some margarines
• Cottage cheese, cream cheese
• Hard cheese
• Yogurt
• Ice cream, Ice milk, sherbet
• Breastmilk
FOOD LIST FOR LOW GALACTOSE FOOD
PATTERN

23. COMMON DRUGS USED AND POTENTIAL SIDE
EFFECTS
 For persons with galactosemia, eliminate drugs containing lactose;
supplement with calcium and riboflavin.
 All vitamin–mineral supplements must be free of the non-tolerated
carbohydrates.
 If liver transplantation is needed, support the immunosuppression with
appropriate nutrition interventions.
 Changes in fluid or sodium or other nutrients may be required.

24. NUTRITION EDUCATION AND COUNSELLING
Counselling should be given to the patients about
 Which sources of carbohydrate are allowed specific to the disorder.
 Reading the labels carefully. Many foods contain milk solids, galactose and
other sugars; omit according to the disorder.

26. SOURCES AND REFERENCES
 Marcia Nelms, Kathryn P. Sucher, Nutrition Therapy & Pathophysiology, 4th Edition,
Cengage, Pages 775 - 776
 Kathleen Mahan L., Janice L. Raymond, Krause’s Food and Nutrition Care Process, 14th
Edition, Elsevier, Pages 904 – 905
 Sylvia Escott-Stump, Nutrition and Diagnosis - Related Care, 7th Edition, Lippincott
Williams and Wilkins, Pages 155 – 157
 Sardesai, Vishwanath, Introduction to Clinical Nutrition, 3rd Edition, CRC Press, Pages 443
- 444
 Lindsey Welling, et al. International clinical guideline for the management of classical
galactosemia: diagnosis, treatment, and follow-up, 17 November 2017,
www.springerlink.com
 https://rarediseases.info.nih.gov/diseases/2424/galactosemia
 http://www.galactosemia.org/understanding-galactosemia
 https://www.childrenshospital.org/conditions-and-
treatments/conditions/g/galactosemia/symptoms-and-causes
 https://www.msdmanuals.com/professional/pediatrics/inherited-disorders-of-
metabolism/galactosemia
 https://rarediseases.org/rare-diseases/galactosemia/#.YExf_ZKh6ug.gmail