Pathology for Hemophilia, an example of a genetic disease, particularly, a Mendelian disease.

1. Genetic Disorders:
Mendelian (Monogenic)
Diseases
Prepared by:
Shaina Mavreen D.Villaroza

2. Mendelian Diseases
▪ Definition:
Diseases in which the phenotypes are largely
determined by the action, lack of action, of
mutations at individual loci.
▪ Rare 1 % of all live born individuals
▪ 4 types of inheritance
 Autosomal dominant
 Autosomal recessive
 X linked dominant
 X linked recessive
Example: Hemophilia
©Chromosome theory.
http://chsweb.lr.k12.nj.us/mstanley/outlines/chromotheory/chromot
heory.html

3. Autosomal Dominant
▪ Offspring has a 50:50 chance of being
affected
▪ Both sexes equally affected
▪ Examples
ABO Blood Group System
Retinoblastoma
Neurofibromatosis
Marfan’s syndrome
Familial polyposis coli
©Marfan syndrome. http://intranet.tdmu.edu.ua/data/kafedra/internal/i_nurse/classes_stud/RN-
BSN%20Program/Full%20time%20study/First%20year/professional%20nursing%20role%20transition%20practi
cum/09.%20Practice%20nursing%20care%20to%20clients%20with%20CTD%20II.htm

4. Autosomal Recessive
▪ Probability 25% (1:4)
▪ Both sexes equally affected
▪ Examples
Hemoglobinopathies: sickle cell
anaemia, thalassemia
Inborn errors of
metabolism:PKU,Alkaptonuria……
Albinism
Cystic Fibrosis
Hirschsprung disease
©Google Images
© What causes congenital adrenal hyperplasia (CAH)?
https://www.nichd.nih.gov/health/topics/cah/conditioninfo/Pages/causes.aspx

5. X linked dominant
Affected Father
▪ Daughters are affected, sons
escape
– Examples
 Vitamin D resistant Rickets
 Familial hypophosphatemia
 Blood group Xg
©Vitamin D Metabolism and Rickets.
https://xlhnetwork.org/xlh.pl?f=larry/website/VitaminD/vitaminD.html

6. X-Linked Recessive
Carrier Mother
▪ A mutant gene on X chromosome in
males will express itself readily as there
is no normal allele, but a mutant gene
on X chromosome of females will not
express itself in the presence of a
normal allele
▪ Examples
Hemophilia
Colour blindness
Duchenne muscular dystrophy
G6PD deficiency

7. Hemophilia
X-Linked Recessive
GENERAL
DESCRIPTION and
EPIDEMIOLOGY
▪ Is a heredity blood disease by delayed
blood clotting or the blood doesn’t clot
normally
▪ Absence of factor in blood
antihemophilic globulin
▪ Sex-linked disorder, genes are located on
the X chromosome
©Blood Disorders
http://www.rchsd.org/health-articles/hemophilia/
©Causes, Symptoms AndTreatment Of Hemophilia.
http://mytips10.blogspot.com/2015/07/causes-symptoms-
and-treatment-of-hemophilia.html
©Egyptian Hemophilia NeedsYour Attention.
http://sadtimedays.blogspot.com/2012/08/egyptian-hemophi
needs-your-attention.html
©Hemophilia.
https://suncfb1.wikispaces.com/Hemophilia

8. Hemophilia
Signs and Symptoms
 Spontaneous bleeding
 Prolonged bleeding from cuts
 Nosebleeds with no known cause
 Tightness in your joints
 Internal bleeding
 Bruising, especially a large, lumpy
bruise.
 Blood in the urine or stool
© Hemophilia – Causes, Symptoms, Diagnosis AndTreatment
http://www.doctortipster.com/6480-hemophilia-causes-symptoms-
diagnosis-and-treatment.html
© Stock Photography: Joint Bleeds In Hemophilia.
http://www.dreamstime.com/stock-photography-joint-bleeds-
hemophilia-image27394012
© What is Involved in
Making a Diagnosis of
Hemophilia?
http://www.wisegeek.
com/what-is-involved-
in-making-a-
diagnosis-of-
hemophilia.htm

9. Hemophilia
Pathogenesis
▪ Hemophilia occurs when you
have a deficiency in one of
these clotting factors (platelets
and plasma proteins).
▪ Hemophilia is inherited.
▪ However, in some cases,
hemophilia is caused by a
genetic change (spontaneous
mutation).
▪ Hemophilia A, the most common
type, is caused by insufficient
clotting factorVIII.
▪ Hemophilia B, the second most
common type, is caused by
insufficient clotting factor IX.
▪ Hemophilia C, in which signs and
symptoms are often mild, is
caused by insufficient clotting
factor XI.
(C) ‘Hemophilia patient dies in
drug-deficient hospital.
http://www.greaterkashmir.com/
news/health/-hemophilia-
patient-dies-in-drug-deficient-
hospital/208387.html

10. Hemophilia
Current Treatment
▪ No cure, yet.
▪ But can be treated:
▪ Treatment for bleeding episodes
▪ Mild hemophilia A. Slow injection of the hormone
desmopressin (DDAVP) into a vein can stimulate a
release of more clotting factor to stop bleeding.
Occasionally, DDAVP is given as a nasal medication.
▪ Moderate to severe hemophilia A or hemophilia B.
Bleeding may stop only after an infusion of recombinant
clotting factor or clotting factor derived from donated
human blood. Repeated infusions may be needed if
internal bleeding is severe.
▪ Hemophilia C. Clotting factor XI, the factor missing in
this type of hemophilia, is available only in Europe. In the
United States, plasma infusions are needed to stop
bleeding episodes.
▪ Ongoing treatment
Regular infusions of DDAVP or clotting
factor
Clot-preserving medications
(antifibrinolytics)
Fibrin sealants
Physical therapy
First aid for minor cuts
Vaccinations

11. References:
▪ Diseases and Conditions Hemophilia. Published on September 26, 2014. Retrieved on May 1, 2016 from
http://www.mayoclinic.org/diseases-conditions/hemophilia/basics/definition/con-20029824
▪ Hemophilia Treatments and drugs. Retrieved on May 1, 2016 from http://www.mayoclinic.org/diseases-
conditions/hemophilia/basics/treatment/con-20029824
▪ Symptoms of Hemophilia. Retrieved on May 1, 2016 from http://www.seattlechildrens.org/medical-
conditions/chromosomal-genetic-conditions/hemophilia-symptoms/