Question

Case Study #2: The Case of Ruby Rhod: Severe Immunodeficiency from Loss of B and T Cells
At birth, Ruby seemed to be a normal healthy baby. However, soon after birth, his mother
noticed that he developed numerous abnormalities with his health, including numerous
pus-filled blisters. He was admitted to the hospital, where his condition rapidly worsened.
He developed enlarged lymph nodes in his neck, armpits, and groin. Medical personnel
identified both Staphylococcus aureus and Candida albicans in pus from the blisters. He
also showed signs and symptoms of staphylococcal and fungal infections over his body,
including in his throat and on his skin. Antibacterial and antifungal treatment was
initiated; however, blood tests were completed as well. The blood panel results revealed
an absence of B cells and non-functioning T cells. Genetic testing was performed to identify
cause of this deficiency in his B and T cells. RAG1 and RAG2 genes were sequenced and a
deleterious mutation was identified in the genes, which caused the loss of B and T cells.
Ruby was diagnosed with Omenn Syndrome, a form of Severe Combined Immunodeficiency
(SCID). While identifying the medical cause for Ruby’s ailment, he developed a severe case
of pneumonia caused by Pneumocystis jirovecii, which ultimately led to his death.

1. What is SCID? What are the various forms of SCID? How do these arise? There are
over 10 forms of SCID…a table may be used for this answer. Be sure to also note
what Omenn Syndrome is, what the symptoms of Omenn Syndrome are, and how
the disease arises.

note you answering person must provide the table...

Answer 1

SEVERE COMBINED IMMUNODEFICIENCY (SCID) is an inherited primary immunodeficiency disease. The child born with SCID has a very little or no immune system as a result, the child's body is unable to fight off infections. Children with this rare, inherited disease become very ill with illnesses such as pneumonia, meningitis, and chickenpox and can die within the first year of their life. There are several types of SCID, but two most common types are the classical X-linked (inherited on the X chromosome and only affects males) and the ADA or Adenosine deaminase deficiency (low levels of the enzyme ADA resulting in no production of T and B cells) ADA is involved in purine metabolism. Its primary function in humans is the development and maintenance of the immune system. Several types of SCID are shown below in the table-

Omenn syndrome is an autosomal recessive form of severe combined immunodeficiency (SCID).

Symptoms- erythroderma (skin redness), desquamation (peeling skin), alopecia (hair loss), chronic diarrhoea, failure to thrive, lymphadenopathy (enlarged lymph nodes), eosinophilia, hepatosplenomegaly, and elevated serum IgE levels.

infants with Omenn syndrome typically present shortly after birth, usually by 3 months of age.

Cause - mutations in RAG genes cause this syndrome. This results in non-functional T and B cells. Few other gene mutations can also result in the rare Omenn syndrome. These are- ARTEMIS, ADA, ILRA2, ILRA7, CHD7, and DNA ligase 4.

Treatment- bone marrow transplant antibiotics and gene therapy

Inheritance of Omenn syndrome-

Oo x Oo

carrier father x carrier mother

	O	o
O	OO	Oo
o	Oo	oo

OO- 25% normal

Oo- 50% carrier

oo- 25% affected with omenn syndrome