0 X linked Dominant disorders

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X linked Dominant disorders

• Rett Syndrome (Only seen in female - as it is lethal in males)

• Urea cycle disorder (OTC deficiency )

• Familial hypophosphatemic Rickets

• Incontinentia Pigmenti

• Alport Syndrome (can be AR and AD also but MC it is X-D)

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0 Chromosome 22

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CHROMOSOME 22 :

• Meningioma

• Neurofibromatosis 2 ( merlin )

• Acoustic Neuroma

• Di George syndrome

• Velocardiofacial syndrome

Note: 

NF1 - Chromosome 17

NF2 - Chromosome 22

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0 Chromosome 21

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CHROMOSOME 21 :

• Down syndrome (Trisomy) 

• Amyloidosis 

• Reduced folate carrier ( SLC19A1 ) ( Folate Transporter ) 

• Homocystinuria 

Note :

• Folate Receptor genes (FOLR 1 adult , FOLR 2 fetal , FOLR 3 ) are mapped on Chromosome 11 

• Reduced folate carrier (SLC19A1) (Folate Transporter) - Chromosome 21.

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0 Chromosome 20

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CHROMOSOME 20 :

• Severe combined immunodeficiencydisease (SCID) - (characterized by a deficiency of the enzyme adenosine deaminase ) 

• Type 1 MODY 

Note:

• SCID - Most common form is X-Linked recessive (so k/a - X linked SCID ) 
• Type 2 MODY - Chromosome 7

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0 Chromosome 19

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CHROMOSOME 19 :

• Myotonia dystrophica

• Insulin receptor gene

• NPHS 1 (Nephrin) - Congenital FINNISH type of Nephrotic Syndrome (AR)

Note :

NPHS 1 - Chromosome 19

NPHS 2 - Chromosome 1

Human Insulin gene - Chromosome 11
Insulin Receptor gene - Chromosome 19

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0 Chromosome 18

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CHROMOSOME 18 :

• Edwards syndrome ( Trisomy )( MC syndrome linked to Chromosome 18)

• de Grouchy Syndrome (distal 18p - ) (2nd MC)

• Pitt-Hopkins syndrome 

• Bipolar disorder 

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0 Chromosome 17

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CHROMOSOME 17 :

• p53 gene

• Neurofibromatosis 1 (neurofibromin gene - NF1 )

• Medulloblastoma

• BRCA 1 

• Canavan disease

• Small Patella Syndrome.

Note :

BRCA 1 - Chromosome 17

BRCA 2 - Chromosome 13

NF1 - Chromosome 17

NF2 - Chromosome 22

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0 Chromosome 16

CHROMOSOME 16 :

• ADPKD (PKD 1)
• Alpha thallesemia
• Pseudoxanthoma elasticum
• Tomm Harsfall protein's gene (UMOD)

Note: 

Beta Thallesemia - Chromosome 11

Alpha thallesemia - Chromosome 16


ADPKD

• Chromosome 16 ( Gene - PKD 1 ) (85% of cases) 
• Chromosome 4 (Gene - PKD 2 ) 

ARPKD - Chromosome 6 ( Gene - PKHD 1 )

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1 Chromosome 15

CHROMOSOME 15 :

• Albinism
• Angelman syndrome (Maternal deletion or Paternal Disomy)
• Prader willi syndrome (Paternal Deletion or Maternal Disomy)
• Tay Sachs disease.
• Marfan syndrome.
• Bloom syndrome. 

Point to note : 

Fibrillin gene 1 (FBN 1) - On chromosome 15 - Marfan's Syndrome.

Fibrillin gene 2 (FBN 2) - On chromosome 5 - Beals syndrome

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Mnemonic :
Its usually confusing to remember Prader willi and Angelman , deletion or disomy , maternal or paternal.

So here is the way

Prader Willi -- is Paternal Deletion (or maternal uniparental disomy) and Angelman's is vice-a-versa.

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0 Chromosome 14

CHROMOSOME 14 :

• Alpha 1 antitrypsin deficiency
• Familial HOCM
• Krabbe disease
• Niemann pick type C (NPC2 gene) (5% cases of type C)

Note: 

Niemann pick disease

Type A - Chromosome 11

Type B - Chromosome 11

Type C 

• NPC1 - Chromosome 18
• NPC2 - Chromosome 14

Approximately 95% of Niemann–Pick Type C cases are caused by genetic mutations in the NPC1 gene, referred to as type C1;

5% are caused by mutations in the NPC2 gene, referred to as type C2.

0 Chromosome 12 & 13

CHROMOSOME 12 :

• Phenylketonuria (q)
• Holt Oram syndrome
• vWF

CHROMOSOME 13 :

• Wilson disease 
• Retinoblastoma 
• Osteosarcoma 
• BRCA 2
• Patau Syndrome (Trisomy)

Note :

BRCA 1 - Chromosome 17

BRCA 2 - Chromosome 13

0 Chromosome 10 & 11

CHROMOSOME 10 :

• RET protoncogene
• MEN 2

Note : 

MEN 1 - Chromosome 11

MEN 2 - Chromosome 10

CHROMOSOME 11 :

• Sickle cell dis.
• Wilms tumour 
• Ataxia telangiectasia
• Beta thallesemia
• MEN 1
• Human insulin gene.
• PTH gene
• Niemann pick disease (Type A & B )
• Folate Receptor genes

Note:
Alpha thallesemia - Chromosome 16
Beta thallesmia - Chromosome 11

Folate Receptor genes (FOLR 1 adult , FOLR 2 fetal , FOLR 3 ) are mapped on Chromosome 11
Reduced folate carrier (SLC19A1) (Folate Transporter) - Chromosome 21.



Human Insulin gene - Chromosome 11
Insulin Receptor gene - Chromosome 19

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0 Chromosome 9

CHROMOSOME 9 : 

• ABO blood group antigens
• Friedreich's ataxia (its a GAA repeat)

Gorlin syndrome can also be associated with 9q22.3 microdeletion

0 Chromosome 7 & 8

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CHROMOSOME 7 :

• Cystic fibrosis
• Type 2 MODY

CHROMOSOME 8 :

• Osteoporosis
• Hereditary Spherocytosis (AD)

Note :

Type 1 MODY - Chromosome 20

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1 Chromosome 6

CHROMOSOME 6 :

• MHC Complex (p)-short arm
• ARPKD
• Hemochromatosis
• Cleidocranial dystosis 

Remember :

ADPKD - Chromosome 16 ( Gene - PKD 1 ) (85% of cases)
                 Chromosome 4 (Gene - PKD 2 )

ARPKD - Chromosome 6 ( Gene - PKHD 1 )

0 Chromosome 5

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CHROMOSOME 5 :

• FAP (APC gene) 
• Beals syndrome = Congenital Contractual Arachnodactyly (FBN 2)
• Treacher collins syndrome
• Cri du chat syndrome (5p deletion)

Point to note :

Fibrillin gene 1 (FBN 1) - On chromosome 15 - Marfan's Syndrome.

Fibrillin gene 2 (FBN 2) - On chromosome 5 - Beals syndrome

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0 Chromosome 4

CHROMOSOME 4 :

• Huntington chorea
• Parkinsonism 
• Achondroplasia
• ADPKD (Gene - PKD 2 )

Remember :

ADPKD - Chromosome 16 ( Gene - PKD 1 ) (85% of cases)
                 Chromosome 4 (Gene - PKD 2 )

ARPKD - Chromosome 6 ( Gene - PKHD 1 )

0 Chromosome 2 & 3

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CHROMOSOME 2 :

• HNPCC (MSH 2)
• Cysteinuria

CHROMOSOME 3 :

• HNPCC (MLH 1) 
• VHL
• Alkaptonuria

The majority of HNPCC ( hereditary non-polyposis colorectal cancer ) is caused by mutations in one of several mismatch-repair genes:

MSH2, MSH6, and PMS1 on chromosome 2, 

MLH1 on chromosome 3, 

MSH3 on chromosome 5, and 

PMS2 on chromosome 7. 

MSH2 and MLH1 account for the majority of mutations in HNPCC families.

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MedicoNotebook - Founder : DrShiviMudgal , Co-Founder : DrAyushGoel

0 Chromosome 1

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CHROMOSOME 1 :

• Rh system 

• Neuroblastoma

• NPHS 2 (podocin)

• Primary open angle glaucoma (MYOC gene coding myocilin protein) 

Note :

NPHS 1 - Chromosome 19

NPHS 2 - Chromosome 1

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0 Autosomal recessive disorders

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Mnemonic for autosomal recessive disorders :

ABCDEFGH

A – Albinism.
B – Beta thalessemia.
C – Cystic Fibrosis.
D – Deafness
E – Emphysema (alpha-1 Antitrypsin Deficiency).
F – Friedrichs ataxia
G – Gauchers disease
H – Homocystinuria, Hemochromatosis.

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