Prevalence and Incidence of SCID
Prevalance of SCID:
approximately 1-per-500,000 (NIDCD); 1-per-million ... see also overview of SCID.
Prevalance Rate:
approx 1 in 500,000 or 0.00% or 543 people in USA [Source statistic for calcuation: "approximately 1-per-500,000 (NIDCD); 1-per-million" -- see also general information about data sources]
SCID: Rare Disease
SCID is listed as a "rare disease" by the Office of
Rare Diseases (ORD) of the National Institutes of Health
(NIH). This means that SCID, or a subtype of SCID,
affects less than 200,000 people in the US population.
SCID Prevalence: Book Excerpts
Prevalance of SCID:
Approximately one in
every million people develop SCID (Source: excerpt from Primary Immune Deficiency, NIAID Fact Sheet: NIAID)
Prevalence/Incidence of SCID: Online Medical Books
16 MEDICAL BOOKS ONLINE!
Review excerpts from medical books online, free, without registration,
for more information about the prevalence and/or incidence of SCID.
Severe combined immunodeficiency disease:
Causes and incidence
(Professional Guide to Diseases (Eighth Edition))
SCID is usually transmitted as an autosomal recessive trait, although it may be X-linked. In most cases, the genetic defect seems associated with failure of the stem cell to differentiate into T and B lymphocytes. Many molecular defects such as mutation of the kinase ZAP-70 can cause SCID. X-linked SCID is due to a mutation of a subunit of the interleukin (IL)-2, IL-4, and IL-7 receptors. Less commonly, it results from an enzyme deficiency.
SCID affects more males than females. Its estimated incidence is 1 in every 100,000 to 500,000 births. Most untreated patients die from infection within 1 year of birth.
» READ BOOK EXCERPT ONLINE »
Source: Professional Guide to Diseases (Eighth Edition), 2005
Cough - Case 4-2: 7-Week-Old Boy:
III. Incidence and Epidemiology
(Pediatric Complaints and Diagnostic Dilemmas)
VSDs are the most common cardiac malformation seen in children. Recent studies
have shown the incidence of VSD in newborns to be 5 to 50 per 1,000 children,
with a slight female predominance. VSDs are the most common form of congenital
heart disease associated with chromosomal disorders.
VSDs are classified into four types: perimembranous (80%), outlet (5% to 7%),
inlet (5% to 8%), and muscular (5% to 20%). Muscular defects have the greatest
likelihood of undergoing spontaneous closure. Approximately 75% to 80% of all
VSDs close spontaneously, most often by 2 years of age.
» READ BOOK EXCERPT ONLINE »
Source: Pediatric Complaints and Diagnostic Dilemmas, 2003
Cough - Case 4-6: 4-Month-Old Boy:
III. Incidence and Epidemiology
(Pediatric Complaints and Diagnostic Dilemmas)
B. pertussis, a gram-negative bacillus, is the causative organism for what is commonly
referred to as whooping cough. A whooping cough syndrome can also be seen with
Bordetella parapertussis, M. pneumoniae, C. trachomatis, Chlamydia pneumoniae, and some adenoviruses.
Pertussis is considered one of the most highly communicable diseases, with
transmission occurring via contact with respiratory tract secretions of an
infected patient. With waning immunity from childhood vaccination, adults and
adolescents are commonly the source of infection in infants and young children.
The true incidence of pertussis is unknown, because many cases in adolescents
and adults are unrecognized. However, it is known to be a worldwide threat,
with an estimated 40,000,000 cases and 360,000
deaths per year. In general, the disease is endemic, but there are 3- to 5-year
cycles of epidemics that occur in addition to the endemic levels. For unknown
reasons, girls are affected at much higher rates and with higher morbidity than
boys.
» READ BOOK EXCERPT ONLINE »
Source: Pediatric Complaints and Diagnostic Dilemmas, 2003
Diarrhea - Case 17-1: 2-Month-Old Boy:
III. Incidence and Epidemiology
(Pediatric Complaints and Diagnostic Dilemmas)
The incidence of inguinal hernia is estimated to be between 1% and 5%, or
approximately 10 to 20 cases per 1,000 live births. The incidence in premature
infants is significantly higher, approaching 30%. The ratio of boys to girls is
6:1. In boys, the right side is more frequently involved than the left,
presumably due to the embryologic origin of inguinal hernias through a patent
processus vaginalis and the fact that the right testis descends later during
gestation than the left. In both boys and girls, 60% of inguinal hernias occur
on the right, 30% on the left, and 10% bilaterally. Inguinal hernias are
usually diagnosed during the first year of life, most frequently during the
first month. There is often a family history of inguinal hernia. Undescended
testes may be associated with inguinal hernias. Other conditions associated
with inguinal hernias include Ehlers-Danlos syndrome, cystic fibrosis,
congenital cytomegalovirus infection, and testicular feminization. There is no
apparent ethnic or racial predisposition to inguinal hernia. Incarcerated
inguinal hernias occur most frequently before 6 months of age, are less common
after 2 years of age, and are rare after 5 years of age.
» READ BOOK EXCERPT ONLINE »
Source: Pediatric Complaints and Diagnostic Dilemmas, 2003
Diarrhea - Case 17-4: 15-Month-Old Boy:
III. Incidence and Epidemiology
(Pediatric Complaints and Diagnostic Dilemmas)
The annual incidence of neuroblastoma is approximately 8 per 1 million children
younger than 15 years of age. The median age at diagnosis is 22 months, and 95%
of cases are diagnosed by the age of 10 years. Neuroblastoma accounts for
approximately 6% of all pediatric tumors. There is a slight male preponderance,
with a ratio of 1.2:1. There also appear to be cases that are familial in
nature and manifest at a younger age, with a median age of 9 months at
diagnosis. These tumors derive from postganglionic sympathetic cells found in
the paraspinal sympathetic ganglia and in the adrenal chromaffin cells.
Neuroblastoma and ganglioneuroblastoma represent the malignant forms of these
neural crest tumors, whereas ganglioneuroma represents the most benign form,
with no metastatic potential.
» READ BOOK EXCERPT ONLINE »
Source: Pediatric Complaints and Diagnostic Dilemmas, 2003
Jaundice - Case 15-3: 2-Month-Old Boy:
III. Incidence and Epidemiology
(Pediatric Complaints and Diagnostic Dilemmas)
Congenital hypothyroidism has been estimated to occur in about 1 of every 4,000
newborns, and about one third of these infants demonstrate prolonged
hyperbilirubinemia. It appears that T4 is necessary to the bilirubin
conjugating process. The baby in this case had hypothyroidism and protracted
unconjugated bilirubinemia as dominant features of an even rarer
endocrinopathy, congenital hypopituitarism. Of note, the hyperbilirubinemia
seen in panhypopituitarism can also be
cholestatic, particularly when growth hormone or corticotropin (ACTH) deficiencies dominate
the pathophysiology.
» READ BOOK EXCERPT ONLINE »
Source: Pediatric Complaints and Diagnostic Dilemmas, 2003
Pallor - Case 10-1: 3-Week-Old Boy:
III. Incidence and Epidemiology
(Pediatric Complaints and Diagnostic Dilemmas)
The precise incidence of Diamond-Blackfan anemia is not known. For all the RBC
aplasias, it is estimated that there are 300 to 1,000 new cases annually in the
United States. Diamond-Blackfan anemia occurs primarily in infancy. In some
studies, 10% of patients are anemic at birth, 25% by 1 month, 50% by 3 months,
and 70% by 1 year. This anemia is seen in all ethnic groups, but primarily in
Caucasians. There is no gender predominance.
» READ BOOK EXCERPT ONLINE »
Source: Pediatric Complaints and Diagnostic Dilemmas, 2003
Pallor - Case 10-3: 5-Month-Old Boy:
III. Incidence and Epidemiology
(Pediatric Complaints and Diagnostic Dilemmas)
AHA occurs as the result of binding of antibody, antibody and complement
complex, or complement to the RBC. The resulting immunologic reaction destroys
RBCs and causes anemia. Infectious agents, drugs, and other agents may
stimulate the process. Some autoimmune diseases, such as systemic lupus
erythematosus, may also generate anti-RBC antibodies and RBC destruction. The
true incidence of AHA is unknown, but is estimated to be 1 to 3 cases per
100,000 population per year. Acute AHA usually manifests in the first 4 years
of life.
» READ BOOK EXCERPT ONLINE »
Source: Pediatric Complaints and Diagnostic Dilemmas, 2003
Seizures - Case 19-3: 8-Month-Old Boy:
III. Incidence and Epidemiology
(Pediatric Complaints and Diagnostic Dilemmas)
The GSDs, or glycogenoses, comprise several inherited diseases caused by
deficiency in one of the enzymes that regulate the synthesis or degradation of
glycogen. The end result is abnormal accumulation of glycogen in various
tissues. GSD type I has an estimated incidence of 1 in 200,000 births. GSD IA
is caused by deficiency of the enzyme G6P, which catalyzes the breakdown of
stored glycogen into glucose for use by the body. At least 56 different
mutations in the gene for G6P (chromosome 17q21) have been found in patients
with GSD IA. Failure of the G6P transporter (GSD IB) or of the microsomal
phosphate transporter (GSD IC) also ultimately impair G6P activity. The three
types of GSD result in similar clinical and biochemical disturbances. G6P is
expressed in the liver, kidneys, and intestines.
» READ BOOK EXCERPT ONLINE »
Source: Pediatric Complaints and Diagnostic Dilemmas, 2003
Vomiting - Case 3-1: 7-Week-Old Boy:
III. Incidence and Epidemiology of Methemoglobinemia
(Pediatric Complaints and Diagnostic Dilemmas)
Although methemoglobinemia is a rare condition in pediatrics, it can cause
significant cyanosis and even death. Methemoglobin is a derivative of normal
hemoglobin in which the iron component has been oxidized from the ferrous (Fe
2+) to the ferric (Fe3+) state. The oxidized iron (Fe3+) is unable to reversibly bind oxygen. Therefore, the oxidation of hemoglobin to
methemoglobin produces a functional anemia by impairing the ability of the
blood to transport oxygen. Methemoglobin occurs regularly in the body but
rarely exceeds levels of 2% of the total hemoglobin because of antioxidant
reactions in the body that reduce methemoglobin back to hemoglobin. The most
important of these antioxidant reactions uses either reduced nicotinamide
adenine dinucleotide (NADH)
–cytochrome b5 reductase or NADH phosphate (NADPH)–methemoglobin reductase. NADPH-methemoglobin reductase also reduces methylene
blue, an action that has important therapeutic implications, as described in
the treatment section below.
Methemoglobin levels increase when there is a disturbance in the balance between
the oxidation and reduction of heme iron. Infants are at an increased risk for
methemoglobinemia for two main reasons: (a) young infants have a lower level of
the reductase enzymes, and (b) fetal hemoglobin is more easily oxidized than
adult hemoglobin. Methemoglobinemia can be caused by exposure to oxidant drugs,
development of acidosis, or inherited conditions. The most common oxidizing
agents in acquired methemoglobinemia are sulfonamides, aniline dyes, chlorates,
quinones, benzocaine, lidocaine, metoclopramide, and phenytoin. Ingestion of
well water nitrates can also cause methemoglobinemia. Gastroenteritis with
acidosis can cause methemoglobinemia in infants, especially when
nitrite-forming bacteria such as
Escherichia coli and Campylobacter jejuni are present. Less common causes are inherited deficiencies of erythrocyte
methemoglobin reductase or the presence of M hemoglobin.
» READ BOOK EXCERPT ONLINE »
Source: Pediatric Complaints and Diagnostic Dilemmas, 2003
Wheezing - Case 1-3: 5-Week-Old Boy:
III. Incidence and Anatomy
(Pediatric Complaints and Diagnostic Dilemmas)
The term pulmonary sequestration refers to a congenital malformation consisting of abnormally developed pulmonary
parenchyma that is separate from the normal lung. The tissue is nonfunctioning,
does not communicate with the tracheobronchial tree, and derives its blood
supply from the aorta. There may be a single large anomalous artery, but
occasionally multiple small anomalous arteries from above or below the
diaphragm supply the sequestered lobe. The venous drainage may be pulmonary or
systemic (inferior vena cava, azygous vein, or portal vein). Drainage into
systemic veins produces a left-to-right shunt. In this case, the vessels
appeared to drain into the azygous and hemiazygous veins.
The overall incidence of pulmonary sequestration is not well defined, but
sequestrations have been found in 1% to 2% of all resected pulmonary specimens.
Pulmonary sequestration occurs when an accessory lung bud originates during
embryonic development. If the bud originates early, the sequestration is
considered intralobar, because the normal and sequestered lung share a common
pleural covering. If the bud originates later, the sequestration is considered
extralobar, because the sequestered lung has its own pleura. About 75% of
reported cases of pulmonary sequestration are intralobar; 1% have both an
intralobar and an extralobar component.
Associated malformations occur in 60% of extralobar sequestrations and 10% of
intralobar sequestrations. The most common associated malformations are
duplications of the colon or terminal ileum, esophageal cysts or
communications, vertebral or rib anomalies, diaphragmatic hernia, and
congenital heart disease. Pulmonary sequestration is left-sided in 90% of cases
and bilateral in fewer than 0.5% of cases. Approximately two thirds of all
cases involve the left lower lobe.
» READ BOOK EXCERPT ONLINE »
Source: Pediatric Complaints and Diagnostic Dilemmas, 2003
Wheezing - Case 1-5: 5-Week-Old Boy:
III. Incidence and Epidemiology
(Pediatric Complaints and Diagnostic Dilemmas)
TAPVC defines an anomaly in which there is no direct connection between the
pulmonary veins and the left atrium. Instead, the pulmonary veins merge to form
a common pulmonary vein that connects either to one of the systemic veins or
directly to the right atrium. The malformation does not compromise fetal
circulation during intrauterine life, because pulmonary arterial resistance is
high and some blood flows to the systemic circulation through the patent
foramen ovale. The combined systemic and pulmonary blood flow to the lungs is
only mildly elevated. After birth, as pulmonary resistance falls, a
progressively larger proportion of the mixed venous blood flows to the lungs,
causing massive pulmonary overcirculation.
Several classification schemes have been proposed based on physiologic or
prognostic implications of the anomalous connections. Generally, the
connections are divided by whether the pulmonary veins merge with the coronary
sinus of the right atrium (cardiac) or with the systemic venous circulation
above the diaphragm (supracardiac) or below it (infradiaphragmatic).
Approximately 75% of the connections are supracardiac, with the left innominate
vein, coronary sinus, and superior vena cava serving as the most common
anatomic sites of connection.
In TAPVC, because all venous blood ultimately returns to the right atrium, a
communication between the right and left sides of the heart is necessary to
sustain life. A patent foramen ovale or an atrial septal defect allows free
communication between the two atria and, therefore, is considered part of the
disorder. Other intracardiac anomalies occur in up to one third of cases and
include common atrioventricular canal, transposition of the great arteries,
tetralogy of Fallot, and hypoplastic left heart syndrome. TAPVC with drainage
directly into the right atrium occurs in patients with visceral heterotaxy and
polysplenia.
The incidence of TAPVC is not clear. TAPVC occurred in 2% of cases in an autopsy
series of 800 children with congenital cardiac disease who died during the
first year of life. TAPVC also occurred in 41 (1.5%) of 2,659 infants with
cardiovascular malformations identified in the Baltimore-Washington Infant
Study. Infradiaphragmatic TAPVC is more prevalent in boys (male:female ratio,
3:1). There is no sex prevalence in TAPVC with other sites of connection.
» READ BOOK EXCERPT ONLINE »
Source: Pediatric Complaints and Diagnostic Dilemmas, 2003
Wheezing - Case 1-6: 4-Month-Old Boy:
III. Incidence and Epidemiology
(Pediatric Complaints and Diagnostic Dilemmas)
P. carinii is an opportunistic parasite with some features of protozoa but greater genetic
homology to fungi. Approximately 85% of immunocompetent children develop
asymptomatic primary infection by 3 years of age. Severe PCP after primary
infection occurs in immunocompromised infants and children.
The risk of PCP is related to the extent of immunosuppression and the use of
chemoprophylaxis. PCP occurs in children with the acquired immunodeficiency
syndrome (AIDS, 25% to 50%), severe combined immunodeficiency syndrome (25% to
50%), acute lymphocytic leukemia (10% to 20%), allogeneic bone marrow
transplantation (5%), and organ transplantation (2% to 10%) if no
chemoprophylaxis is given. Use of TMP-SMX prophylaxis reduces the PCP rate to
less than 5% in HIV-infected children. Children receiving agents that impair
cell-mediated immunity, including corticosteroids and cyclosporine, are at even
greater risk of developing PCP. Patients with a history of PCP are at high risk
for recurrence.
» READ BOOK EXCERPT ONLINE »
Source: Pediatric Complaints and Diagnostic Dilemmas, 2003
Immune Deficiency:
Immune Deficiency - epidemiology
(The 5-Minute Pediatric Consult)
Immune Deficiency - prevalence
Most common immunodeficiency is IgA deficiency, with an estimated prevalence of 1:500 people:
- 1:3,000 for chromosome 22q11.2 deletion syndrome (DiGeorge syndrome)
- 1:60,000 for SCID
- 1:200,000 for chronic granulomatous disease
» READ BOOK EXCERPT ONLINE »
Source: The 5-Minute Pediatric Consult, 2008
Severe Combined Immunodeficiency:
Severe Combined Immunodeficiency - epidemiology
(The 5-Minute Pediatric Consult)
- Most patients present by 6 months of age.
- Of severe combined immunodeficiency cases:
- The X-linked form accounts for 50%.
- Adenosine deaminase deficiency accounts for 8%.
- Interleukin-7 receptor deficiency accounts for 10%.
- Janus-associated kinase 3 deficiency accounts for 10%.
Severe Combined Immunodeficiency - incidence
Incidence: Estimated to be 1 in 66,000–100,000 live births
» READ BOOK EXCERPT ONLINE »
Source: The 5-Minute Pediatric Consult, 2008
About prevalence and incidence statistics:
The term 'prevalence' of SCID usually refers to the estimated population
of people who are managing SCID at any given time.
The term 'incidence' of SCID refers to the annual diagnosis rate,
or the number of new cases of SCID diagnosed each year.
Hence, these two statistics types can differ:
a short-lived disease like flu can have high annual incidence but low prevalence,
but a life-long disease like diabetes has a low annual incidence but high prevalence.
For more information see about prevalence and incidence statistics.
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