This document discusses Alagille syndrome (ALGS), a multisystem genetic disorder caused by mutations in the JAG1 gene. It notes that ALGS affects the liver, heart, kidneys, skeletal system, and facial features. Methods for studying the JAG1 gene discussed include DNA extraction, DHPLC, RT-PCR, sequencing, and identifying mutations through these techniques. Authors cited agree that identifying mutations is important for diagnosis and understanding ALGS, but that not all cases may be explained by known JAG1 mutations. Improving newborn screening and public access to genomic testing could help advance understanding of ALGS.

1. Danny Arroyave Zuluaga
Sergio Andrés Romero Seguro
TERCER SEMESTRE
PROFESORA: LINA MARIA MARTINEZ

2. 




Is a multisystem disorder with an autosomic
dominant pattern.
20–89% of the cases to mutations in the JAG1
gene.
JAG1 gene is located at 20p12.2.
Presents so far more than 300 mutations.
ALGS has been one of the main reasons for
referral for transplantation of liver.

3. organ
alteration
Liver
particularly presenting bile duct paucity
heart
peripheral pulmonary artery stenosis
kidneys
renal dysplasia, renal tubular acidosis, among others
skeletal system
butterfly vertebrae
characteristic
facial
features
broad forehead, deep-set eyes, pointed chin and a
triangular face
eyes

4. Polymorphism
 alternatives are isoforms of a gene in a
population. affects both gonadal and somatic
cells, so it can be transmitted following the
laws of Mendelian inheritance.

Mutations
 permanent change occurred in the base
sequence of the DNA of an organism. are only
affects inheritable when gonadal cells and not
when exclusively affects somatic cells.


5. recognize and investigate the JAG1 gene,
which could help us in the clinical monitoring
of these patients.


6. 
Extracción de Dna:
Ruptura de las celulas (detergentes y
enzimas).
 Eliminacion de proteinas.
 Eliminacion de ARN.
 Extracción de proteinas.
 Precipitaciones del ADN.


7. DHPLC
 Técnica cromatografía para la separación y el
análisis de fragmentos de ADN con diferente
longitud y/o composición de base

RT-PCR
 Amplificación de RNA a través de la síntesis
previa de su DNAc (copia), utilizando una
transcriptasa inversa, seguido de varios ciclos
de PCR convencional. Con esta técnica se
puede determinar la expresión de genes en
diversos tejidos.


8.  Secuenciación

a)
b)
Tiene métodos tanto químicos como
enzimáticos
Químicos: marcaje del DNA, hidrólisis
química selectiva del DNA y análisis de los
productos
Enzimático: síntesis enzimática, análisis de
los fragmentos y automatización

9. 


Su objetico es la amplificación directa de un
gen o un fragmento de DNA o indirecta de un
RNA
Se basa en amplificación enzimática in vitro,
que es el incremento geométrico del numero
de copias de una secuencia particular del
DNA
Técnica metodológica

10. 1.
2.
Desnaturalización: calentamiento para las
separación de las dos hebras de DNA,
mediantes incubación breve a una
temperatura entre 90-97 grados centígrados
Alineamiento: hibridación de las hebras
sencillas del DNA de interés con los primers
y DNTp's. A una temperatura de 37 a 65
grados centígrados

11. 3.
Síntesis: amplificación en la que la DNA
polimerasa elonga los primers empleando
como molde ambas hebras originales. La
replicación transcurre en dirección 5‘ a 3‘.

12. Fig 1. A y C NM por DHPLC ; B y D Electropherogram.

13. Fig 2. Mutación por splicing
Nuevo con especificación entre
La región exon1 a exon2.

14. Fig 3. Perdida de exón 4
confirmada Posterior a
RT PCR.

16. AUTHOR
(Onouchi et al.,
1999)
Heritage et al.
(2002).
WHAT DID HE SAY?
“In the case of the intron
4–5 mutation described
(and as has been
previously reported for
other abnormal splicing
mutation affecting the
following downstream
base in the donor
splicing site), this
change could generate a
less severe phenotype.”
“The present study
further supports the idea
that the molecular
mechanisms involved in
the clinical
effect of the mutations in
ALGS is the
haploinsufficiency mainly
due to the loss of the
transmembranal or
the DSL domains (NMD).
THEY ARE AGREE? YES
OR NOT
NO
YES

17. AUTHOR
(Kamath et al., 2012;
Mc
Daniel et al., 2006).
(Mátyás et al.,
2002).
WHAT DID HE SAY?
“Finally, in our study we
observed that in 2
patients with ALGS clinical
diagnosis there were no
mutations identified in
JAG1, however, we cannot
discard the presence of
mutations in other
regions of the
gene (such as the
promoter) or in NOTCH2
gene”
“It has been
demonstrated that
polymorphic changes
detection is difficult
when there are two
variations in
the same amplicon”
THEY ARE AGREE?
YES OR NOT
YES
YES

18. 1.
2.
Is really important that we (medicine
society), start a process in the early
determination of mutations in the
newborn.
The field of the mutations moves really
fast, and maybe the solution is not try to
stop it, is work hard and fast as they do.

19. 3. We think that it could be a good solution,
the implemetation of a law that allow the
people to make a genomic exam for free.
4. The people should know more about its
history, and where they are from, this would
be really helpful to make a geographic
location and try to know, when all these
things start and where come from.