downs syndrome

Q:1 A 4 year old boy presented with chronic constipation. If you suspectHirschsprung's disease, which of the following statements are incorrect?

A: Delayed (>24 h) meconiumB: Functional constipationC: Affected siblingD: Associated with Down’s Syndrome

Correct Ans:B

Explanation

Constipation in Hirschsprung’s disease is organic not functional.

“Red flags” for Hirschsprung’s disease

Delayed (>24 h) meconium—Present in 7087% of cases of Hirschsprung’sdisease and in <1% of normal childrenNeonatal constipation—Present in 9095% of cases but in <7% of children withfunctional constipationFamily history (affected sibling)—Present in 1233% of casesPoor growth—Present in 2530% of casesAbdominal distension—Present in 7685% of cases but in 20% of patients withfunctional constipationDown’s syndrome and other chromosomal anomalies—Hirschsprung’s disease ispresent in 1.5% of patients with Down’s syndrome, but 510% of patients withDown’s have functional constipation

Ref: 1. Singh SJ, Croaker GDH, Manglick P, Wong CLH, Athanasakos H, Elliott E, et al.Hirschsprung’s disease: the Australian Paediatric Surveillance Unit’s experience. PedSurg Int2003;19:24750.2. National Institute for Health and Clinical Excellence. Diagnosis and management ofidiopathic childhood constipation in primary and secondary care. (Clinical guidance 99.)2010. 3.Hirschsprung’s disease, C Powell ; BMJ 2012;345:e5521.

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Q:2 A patient of 47 XXY karyotype presents with features of hypogonadism; likelydiagnosis is:

A: Turners syndromeB: Klinefelters syndromeC: Edwards syndromeD: Down syndrome

Correct Ans:B

Explanation

The most common pattern Klinefelter’s Syndrome is 47 XXY (other include46,XY/47,XXY mosaicism).

Ref: Male Hypogonadism: Basic, Clinical and Therapeutic Principles By Stephen J.Winters, 2004, Page 159 ; Harrison’s Principles of Internal Medicine, 14th Edition,120 and 15th Edition, Page 2174


Q:3Which among the following can cause congenital heart block?

A: Maternal SLEB: Down’s syndromeC: Edward’s syndromeD: Phenylketonuria

Correct Ans:A

Explanation

SLE with high SSA titer is said to predispose to congenital heartblock in the child.

Complete atrioventricular block (CAVB) occurs in as many as 5%of children born to mothers with antiRo antibody, which can beseen with subclinical or clinical maternal lupus erythematosus,maternal Sjögren syndrome, or another maternal autoimmunedisease. After birth, the children may present with varyingdegrees of heart block, including CAVB, cardiomyopathy, andother manifestations of neonatal lupus syndrome. However, themajority of infants who are born to these mothers do notmanifest AV block.

Hereditary diseases such as Hurler cardiomyopathy and Huntercardiomyopathy can be associated with CAVB.


Q:4A 1 yr old child is with normal intelligence with features of hypotonia. Onexamination there are tongue fasciculations and he keeps his body in a frog likeposition and also loss of reflexes. Give the most probable diagnosis?

A: Guillain Barre SyndromeB: Limb girdle atrophyC: Down’s syndromeD: Spinal muscular atrophy

Correct Ans:D

Explanation

Spinal muscular atrophy type 1 (WerdnigHoffman disease) is the most common causeof a floppy infant syndrome. Children may attain typical "frog posture" or otherpostures on rest. Spinal muscular atrophy (SMA) is an autosomal recessiveneuromuscular disorder in which anterior horn cells in the spinal cord degenerate.

Three clinical subtypes are recognized:

SMA I: The most devastating. Mild weakness may be present at birth but is clearlyevident by 3 months and is accompanied by loss of reflexes and fasciculations inaffected muscles. Progression of the disorder leads to eventual respiratoryfailure, usually by age 1 year.SMA II: Symptoms of SMA II begin later, with weakness and decreased reflexesgenerally apparent by age 2 years. SMA III: Children affected with SMA III begin to become weak as they approachadolescence.

Ref: Tsaic A.C., Manchester D.K., Elias E.R. (2012). Chapter 37. Genetics &Dysmorphology. In W.W. Hay, Jr., M.J. Levin, R.R. Deterding, J.J. Ross, J.M. Sondheimer(Eds), CURRENT Diagnosis & Treatment: Pediatrics, 21e.


Q:5 Transient myeloproliferative disorder of the newborn is usually seen with:

A: Turner syndromeB: NeurofibromatosisC: Downs syndromeD: Ataxia telangiectasia

Correct Ans:C

Explanation

Neonates with Down syndrome are prone to develop transient leukemia ormyeloproliferative syndrome characterised by high leukocyte count, blast cells in theperipheral blood, and associated anemia, thrombocytopenia, and hepatomegaly.

Ref: Kliegman, Behrman, Jenson, Stanton (2008), Chapter 495, “Lymphoma”, In the book, “NELSON TEXTBOOK OF PEDIATRICS”, Volume 2, 18th Edition, New Delhi, Page 2122.


Q:6 All of the following genetic syndromes are associated with Acute MyeloidLeukemia, except:

A: Down's SyndromeB: Klinefelter's SyndromeC: Patau SyndromeD: Turner's Syndrome

Correct Ans:D

Explanation

Of all the options given Turner’s syndrome is not found to be associated with increasedincidence of acute myeloid leukemia (AML). Down's syndrome, Klinefelter's Syndrome,Patau Syndrome are associated with AML.

Ref: Harrison’s Principles of Internal Medicine16th Edition, Page 631; Excellent Carefor Cancer Survivors: A Guide to Fully Meet Their Needs By Kenneth Miller – Pg327; Childhood Leukemia: A Practical Handbook, By Gregory H. Reaman – Pg 11


Q:7 Transient myeloproliferative disorder of the newborn is usually seen with:

A: Turner syndromeB: NeurofibromatosisC: Downs syndromeD: Ataxia telangiectasia

Correct Ans:C

Explanation

Neonates with Down syndrome are prone to develop transient leukemia ormyeloproliferative syndrome characterised by high leukocyte count, blast cells in theperipheral blood, and associated anemia, thrombocytopenia, and hepatomegaly.

Ref: Kliegman, Behrman, Jenson, Stanton (2008), Chapter 495, “Lymphoma”, In the book, “NELSON TEXTBOOK OF PEDIATRICS”, Volume 2, 18th Edition, New Delhi, Page 2122.


Q:8Which is the most common chromosomal anomaly seen?

A: Down’s syndromeB: Turner’s syndromeC: Kinfelter’s syndromeD: Edward’s syndrome

Correct Ans:A

Explanation

Down syndrome is by far the most common and best known chromosomal disorder inhumans and the most common cause of intellectual disability. It is characterized bymental retardation, dysmorphic facial features, and other distinctive phenotypic traits.

Down syndrome is primarily caused by trisomy of chromosome 21; this is the mostcommon trisomy among live births. 21 trisomy is a result of maternal nondisjunction.


Q:9 A male child presented with cryptorchidism, mental retardation and pulmonary stenosis. He has normal karyotype. Which of the following is the diagnosis?

A: Noonan’s syndromeB: Turner’s syndromeC: Down’s syndromeD: Angelmann’s syndrome

Correct Ans:A

Explanation

The karyotype is normal and it is a male child so the diagnosis isNoonan’s syndrome.

Noonan syndrome have normal karyotypes and it is an importantdistinction with Turner's syndrome. Mutations in the RASMAPKsignaling pathway are responsible for Noonan syndrome. Thecardinal features of Noonan syndrome include unusual facies (ie,hypertelorism, downslanting eyes, and webbed neck),congenital heart disease (in 50%), short stature, and chestdeformity. Approximately 25% of individuals with Noonansyndrome have mental retardation. Bleeding diathesis is presentin as many as half of all patients with Noonan syndrome.


Q:10

Physical examination of a neonate is remarkable for a holosystolic murmur.There is no cyanosis.Echocardiography demonstrates an ostium primum defect inthe lower part of the interatrial septum that is accompanied by malformations ofthe adjacent atrioventricular valves. These lesions are most likely associatedwith which of the following disorders?

A: Cystic fibrosisB: Down syndromeC: Gaucher diseaseD: Marfan syndrome

Correct Ans:B

ExplanationThe most common type of atrial septal defect is the ostium secundum type. Childrenwith Down syndrome, however, are frequently afflicted with the ostium primum type ofatrial septal defects, which may be accompanied by tricuspid and mitral valve

malformations. More complex atrioventricular septal defects may also occur in thisdisorder. Children exhibiting these lesions should be specifically evaluated forchromosomal abnormalities. Clinically, the lesions produce lefttoright shunts with latecyanosis (after the right ventricle hypertrophies in response to developing lung diseasefrom the increased blood flow in the pulmonary system).Neither cystic fibrosis nor Gaucher disease is specifically associated with cardiovasculardefects. Dissecting aortic aneurysm is associated with Marfan syndrome . Ref: Tsaic A.C., Manchester D.K., Elias E.R. (2012). Chapter 37. Genetics &Dysmorphology. In W.W. Hay, Jr., M.J. Levin, R.R. Deterding, J.J. Ross, J.M. Sondheimer(Eds), CURRENT Diagnosis & Treatment: Pediatrics, 21e.


Q:11

Physical examination of an infant delivered to a 42 year old, gravida 3, para 2,woman, is remarkable for slight hypotonia and a poor Moro reflex. Furtherexamination reveals upslanting palpebral fissures, epicanthal folds, excessnuchal skin, an enlarged tongue, clinodactyly of the fifth fingers, and a singletransverse palmar crease. Which of the following is the most likely diagnosis?

A: Down syndromeB: Edwards syndromeC: Fetal alcohol syndromeD: Marfan syndrome

Correct Ans:A

ExplanationDown syndrome, or trisomy 21, is the most common autosomal chromosomeabnormality. The incidence increases as maternal age increases. The classic featuresare hypotonia, upslanting palpebral fissures, epicanthal folds, excess nuchal skin, anenlarged tongue, clinodactyly of the fifth fingers, and a single transverse palmarcrease.

Edwards syndrome or trisomy 18, has features of small palpebral fissures, lowset ears,low birth weight, microcephaly, rockerbottom feet, cleft lip, hypotonia, and clenchedhands.

Fetal alcohol syndrome is characterized by growth retardation, small palpebral fissures,smooth philtrum, a thin upper lip, microcephaly, and a short nose. Features often gounnoticed in the newborn period, although sometimes tremulousness and irritabilityoccur.

Marfan syndrome is associated with increased stature, thin limbs, scoliosis, jointhypermobility, and ocular manifestations. Features often go unnoticed in the newbornperiod.

Ref: Hauk P.J., Johnston, Jr. R.B., Liu A.H. (2012). Chapter 33. Immunodeficiency. InW.W. Hay, Jr., M.J. Levin, R.R. Deterding, J.J. Ross, J.M. Sondheimer (Eds),CURRENTDiagnosis & Treatment: Pediatrics, 21e.


Q:12Which of the following conditions is not diagnosed by Chorionic Villous Biopsy?

A: Neural tube defectsB: Down's syndromeC: PhenylketonuriaD: Sickle cell anemia

Correct Ans:A

Explanation

Chorionic villi are an excellent source of DNA thus apt for genetic techniques. It aids inthe prenatal diagnosis of genetic disorders. Chorionic villous sampling is used to detectcytogenetic, biochemical (genetic) or molecular disorders. Neural tube defects are notassociated with any of the above and hence not detected by chronic villous biopsy.

Ref: Dutta textbook of Obstetrics 6th edition; Page 108


Q:13 Increased Nuchal Translucency at 14 weeks gestation is seen in:

A: Turner's syndromeB: Down's syndromeC: HydrocephalusD: Skeletal Dysplasia

Correct Ans:B

ExplanationIncreased nuchal translucency at 1114 weeks of gestation is seen most commonly intrisomies. Many component proteins of extracellular matrix are encoded onchromosome 13,18,21. Altered composition of extracellular matrix account for theincreased nuchal translucency in the trisomies of these chromosomes. Ref: William's Obstetrics, 23rd Edition, Pages 295, 351; Donald School Textbook ofUltrasound in Obstetics and Gynecology, 2nd Edition, Pages 183, 184; Ultrasound in

Obstetrics and Gynaecology By Merz and Bohimann, 2nd Edition, Page 11; DiagnosticImaging of Fetal Anomalies By David A. Nyberg, John P. McGahan, Pages 8458.


Q:14 Alpha feto protein levels are increased in all, EXCEPT:

A: Open neural tube defectsB: Twin pregnancyC: Down's syndromeD: Intrauterine death

Correct Ans:C

Explanation

MSAFP above normal is seen in multiple gestation, when there is placental abruption,as well as in a number of fetal abnormalities, such as neural tube defects includingspina bifida and anencephaly, and abdominal wall defects. Other possibility is error inthe date of the gestation. Mothers with Methylene tetrahydrofolate reductase geneticvariant also have more frequent elevated MSAFP. Abnormally high levels were foundinfrequently in fetal distress and intra uterine fetal death.

MSAFP below normal is associated with a smaller number of conditions, including Downsyndrome and Trisomy 18.


Q:15 A primigravida with abnormal sonographic findings found to have decreasedalpha fetoprotein (AFP) levels. The fetus may have:

A: AnencephalyB: Anterior abdominal wall defectsC: Renal anomaliesD: Down's syndrome

Correct Ans:D

Explanation

AFP is synthesized early in gestation by the fetal yolk sac and later by the fetalgastrointestinal tract and liver. The normal concentration gradient between fetalplasma and maternal serum is on the order of 50,000:1.

Low Levels of AFP seen in:

ObesityDiabetesChromosomal trisomies

Gestational trophoblastic diseaseFetal deathOverestimated gestational age

Selected conditions with high levels of AFP:

Underestimated gestational ageMultifetal gestationNeuraltube defectsGastroschisisOmphaloceleLow maternal weightLiver necrosisRenal anomalies—polycystic kidneys, renal agenesisOsteogenesis imperfecta

Ref: Cunningham F.G., Leveno K.J., Bloom S.L., Hauth J.C., Rouse D.J., Spong C.Y.(2010). Chapter 13. Prenatal Diagnosis and Fetal Therapy. In F.G. Cunningham, K.J.Leveno, S.L. Bloom, J.C. Hauth, D.J. Rouse, C.Y. Spong (Eds), Williams Obstetrics, 23e.


Q:16 A child presents with antimongoloid slant, pulmonary stenosis, short statureand undescended testis. The most likely diagnosis is:

A: Klinefelter syndromeB: Noonan syndromeC: Turner syndrome D: Down syndrome

Correct Ans:B

Explanation

[Noonan syndrome]

Noonan syndrome Autosomal dominant gene with variable expressivity, the gene hasmapped to chromosome 12q. Most common abnormalities are short stature, webbingof neck, pectus carinatum or pectus excavatum, cubitus valgus, right sided congenitalheart disease

·Hypertelorism, epicanthus, downward slanted palpebral fissure, ptosis,micrognathia and ear abnormality·Clinodactyly, moderate mental retardation, high frequency sensorineuralhearing loss is common·The cardiac defect Q is most often pulmonary valvular stenosis, hypertrophiccardiomyopathy or ASD·Low clotting factors XI or XII, ALL and CML have been described·A few patient with neurofibromatosis I and features of Noonan syndrome weresubsequently reported as havinq Turner syndrome, Male frequently have Cryptorchidism and smalltestes, they may be hypogonadal or normal.


Q:17 Anomaly associated with duodenal atresia is?

A: Down syndromeB: Duodenal adenomasC: Limb defectsD: Autoimmune disorders

Correct Ans:A

Explanation

Down syndrome REF: Sabiston 18'h ed chapter 71

Duodenal atresia (DA) is thought to occur as a result of failure of vacuolization of theduodenum from its solid cord stage. The range of anatomic variants includes duodenalstenosis, mucosal web with intact muscular wall (socalled windsock deformity); twoends separated by a fibrous cord, or complete separation with a gap within theduodenum.

Associated Anomalies: DA is associated with several conditions, including prematurity,Down syndrome, maternal polyhydramnios, malrotation, annular pancreas, and biliaryatresia. Other anomalies, such as cardiac, renal, esophageal, and anorectal anomalies,are also common. In most cases, the duodenal obstruction is distal to the ampulla ofVater, and infants present with bilious emesis in the neonatal period. In patients witha mucosal web, the symptoms of postprandial emesis may occur later in life.

Diagnosis: The classic plain abdominal radiograph of DA is termed the doublebubblesign (airfilled stomach and duodenal bulb, In cases in which there is no distal air, thediagnosis is secured, and no further studies are necessary. On the other hand, if distalair is present, an upper gastrointestinal contrast study is performed fairly rapidly.This study is important not only to confirm the diagnosis of duodenal stenosis oratresia but also to exclude midgut volvulus, which would constitute a surgicalemergency.

Treatment: The management of DA is by surgical bypass of the duodenal obstructionas either a sidetoside or proximal transverse—to—distal longitudinal (diamondshaped) duodenoduodenostomy.


Q:18A married middle aged female gives history of repeated abortions for the past 5years. The given below is conceptions prenatal karyogram. This karyogram suggeststhe following

A: Klinefelter's syndrome

B: Turner's syndromeC: Down's syndromeD: Patau's syndrome

Correct Ans:C

Explanation

Ans. is 'c' i.e., Down's syndrome

Most common chromosomal abnormalies causing abortion are chromosomal trisomy.

Trisomy 21 is synonymous with down's syndrome and is the most common of thechromosomal disorders

Trisomy 21 DOWN SYNDROME

Trisomy 18 EDWARD SYNDROME

Trisomy 13 PATAU SYNDROME


Q:19 Glomerulonephritis associated with sensory neural deafness are features of

A: Alport's syndromeB: Nail patella syndromeC: Down's syndromeD: Fabry's syndrome

Correct Ans:A

Explanation

Ans. is 'a' i.e., Alport's syndrome

Alport's syndrome

o Alport's syndrome is a type of hereditary nephritis characterized by ?

(i) Glomerulonephritis progressing to chronic renal failure.

(ii) Nerve deafness

(iii) Eye defects —> lenticonus, lens dislocation, posterior cataract, conicaldystrophy.

Most commonly it is inherited as Xlinked form.Rare autosomal recessive and autosomaldominant pedigrees also exist.

Pathogenesis

o There is defective GBM synthesis because of production of abnormal collagen typeIV underlies the renal lesions. o The defect is caused by mutation in the gene encodinga5chain of collagen type IV.


downs syndrome

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