Most cases of Prader-Willi syndrome are not inherited, particularly those caused by a deletion in the paternal chromosome 15 or by maternal uniparental disomy. These genetic changes occur as random events during the formation of reproductive cells (eggs and sperm) or in early embryonic development. Affected people typically have no history of the disorder in their family.Rarely, a genetic change responsible for Prader-Willi syndrome can be inherited. For example, it is possible for a genetic change that abnormally inactivates genes on the paternal chromosome 15 to be passed from one generation to the next.Prader-Willi syndrome is a complex genetic condition that affects many parts of the body. In infancy, this condition is characterized by weak muscle tone (hypotonia), feeding difficulties, poor growth, and delayed development. Beginning in childhood, affected individuals develop an insatiable appetite, which leads to chronic overeating (hyperphagia) and obesity. Some people with Prader-Willi syndrome, particularly those with obesity, also develop type 2 diabetes (the most common form of diabetes).

Intrauterine growth restriction refers to the failure of the fetus to grow in accordance with the weeks of gestation. There are two types of growth restriction, symmetrical and asymmetrical. Causes include various genetic abnormalities, fetal infections, maternal health conditions, etc. Risk factors for the development of IUGR include fetal echogenic bowel, maternal age above 40 years, low PAPP-A levels, maternal smoking or cocaine use, etc. Fetal echogenic bowel implies a brighter than usual fetal intestines on ultrasonography. It is a marker associated with trisomy 21, which is a cause of IUGR.

The clinical picture suggests that the child is severely dehydrated. IV fluid bolus then IV maintenance fluids is the correct option.

Juvenile angiofibroma (JA) is a rare benign vascular lesion of the skull base that affects young adolescent males. The management of JA is challenged by the abundant vascular blood supply of the lesion, along with the complex anatomy of the skull base and the young age of the affected population. JA typically affects the male population, most commonly between 9 and 19 years of age. The most frequent symptoms are nasal obstruction and epistaxis. Nasal obstruction may be bilateral despite the unilaterality of the lesion, due to nasopharyngeal extension as well as deviation of the nasal septum by the expansile lesion. Epistaxis is usually brisk and intermittent. Purulent nasal discharge and facial pain can be due to sinus drainage pathway obstruction, and conductive hearing loss indicates obstruction of the eustachian tube.

Among the options provided, the most characteristic finding that can be expected in his patient’s urine microscopy is RBC casts. Red cell casts are a characteristic feature of acute nephrotic syndrome. Other options:- Hyaline casts may be seen in normal urine, particularly after exercise. – Coarse granular casts occur in glomerular and tubular disease. – Tubular cell casts may be seen in patients with acute tubular necrosis. – The presence of 10 or more white blood cells/mm3 is abnormal and indicates an inflammatory reaction, most commonly due to infection.

Language/Communication milestones of 2 years old:Points to things or pictures when they are named Knows names of familiar people and body parts Says sentences with 2 to 4 words Follows simple instructions Repeats words overheard in conversation Points to things in a book

Three physical changes – breast budding, pubic hair growth, and axillary hair growth in the order mentioned precede menarche. These changes are due to oestrogen, a hormone essential for pubertal development.The various pubertal changes in males include:-Testicular growth: It is the first sign of puberty occurring at around 12 years of age (Range = 10 – 15 years).- Testicular volume: An increase in the volume of testicles to 4 ml indicates the onset of pubertyThe various pubertal changes in females include:- The first sign is breast development at around 11.5 years of age (range = 9-13 years)- Followed by the onset of height spurt reaching the maximum in puberty (at 12 years of age)- The final change that occurs is termed menarche at 13 (11-15) years of age.Some of the other pubertal changes include:- Gynecomastia may develop in boys- Asymmetrical breast growth may occur in girls- Diffuse enlargement of the thyroid gland

The rational part of a teen’s brain isn’t fully developed until the age of 25 or so.In fact, recent research has found that adult and teen brains work differently. Adults think with the prefrontal cortex, the brain’s rational part. This is the part of the brain that responds to situations with good judgment and an awareness of long-term consequences. Teens process information with the amygdala. This is the emotional part.

Benign neonatal sleep myoclonus (BNSM) is a disorder commonly mistaken for seizures during the new-born period. It is characterized by myoclonic lightninglike jerks of the extremities that exclusively occur during sleep| it is not correlated with epilepsy.Causes of neonatal seizures:Hypoxic-ischemic encephalopathy: Hypoxic-ischemic encephalopathy disrupts the ATP-dependent sodium-potassium pump and appears to cause excessive depolarization.Intracranial haemorrhage: occurs more frequently in premature than in term infants. Subarachnoid haemorrhage is more common in term infants. This type of haemorrhage occurs frequently and is not clinically significant. Typically, infants with subarachnoid haemorrhage appear remarkably well. Metabolic disturbances include hypoglycaemia, hypocalcaemia, and hypomagnesemia. Less frequent metabolic disorders, such as inborn errors of metabolism, are seen more commonly in infants who are older than 72 hours. Typically, they may be seen after the infant starts feeding.Intracranial infections (which should be ruled out vigorously) that are important causes of neonatal seizures include meningitis, encephalitis (including herpes encephalitis), toxoplasmosis, and cytomegalovirus (CMV) infections. The common bacterial pathogens include Escherichia coli and Streptococcus pneumoniae.Cerebral malformationsBenign neonatal seizures

Being anatomically situated immediately posterior to the subclavius muscle and the medial part of the clavicle, the subclavian vein is at the highest risk of injury in the above patient.As a direct tributary of the brachiocephalic vein, it’s injury poses a high risk of massive bleeding.The brachiocephalic vein rests on the first rib, below and in front of the third part of the subclavian artery, and then on scalenus anterior which separates it from the second part of the artery (posteriorly).Anatomy of the clavicle:The clavicle extends from the sternum to the acromion and helps prevent the shoulder falling forwards and downwards.

Fluid replacement therapy should be initiated immediately because the patient is suffering from severe dehydration as shown by the low urine output, the dry mucous membranes and the low skin turgor.

Codman’s triangle is the triangular area of new subperiosteal bone that is created when a lesion, often a tumour, raises the periosteum away from the bone. The main causes for this sign are osteosarcoma, Ewing’s sarcoma, eumycetoma, and a subperiosteal abscess.

Unconjugated bilirubin is conjugated to glucuronic acid in the hepatocyte. Conjugated bilirubin passes into the enterohepatic circulation and the bilirubin which evades this system is metabolised by bacteria, primarily in the large intestine, to urobilinogen, then stercobilinogen and eventually oxidised to stercobilin. Stercobilin gives faeces its brown colour.

Bilious (green) gastric aspirate or emesis indicates that the intestines are obstructed below the ampulla of Vater.Gastrointestinal (GI) endoscopy is actually considered an essential diagnostic and therapeutic technique. Upper GI endoscopy in neonatal age allows for exploration of the oesophagus, stomach and duodenum| instead lower GI endoscopy easily reaches the sigmoid-colon junction.

The most probable diagnosis for the patient would be DiGeorge syndrome due to 22q11 deletion. It causes embryonic defects of the third and fourth branchial arches. It is sporadic in 90% of cases and 10 % inherited from parents as autosomal dominant.Characterised by distinct facial features (micrognathia, cleft palate, short philtrum, and low-set ears), hypocalcaemia, mental retardation, cardiac defects (especially tetralogy of Fallot), and immune deficiencies.A useful memory aid is CATCH-22:- Cardiac defects- Abnormal facial features- Thymic aplasia/hypoplasia- Cleft palate- Hypocalcaemia/Hypoparathyroidism- 22 – Due to 22q11 deletion

Severe cyanotic heart diseases such as pulmonary stenosis, transposition of the great vessels, hypoplastic left heart syndrome and truncus arteriosus all run the risk of a poor prognosis for a neonate. To continue the supply of oxygen the ductus arteriosus must be kept patent. This can be done with the immediate administration of Prostaglandin E1 as a temporary measure until a surgical intervention such as an atrial septostomy can be done. The closure of the duct can subsequently be initiated with the administration of indomethacin and oxygen.

The nerve supply to the tensor tympani is the mandibular nerve.The mandibular nerve is the only division of the trigeminal nerve that carries motor fibres.Tensor tympani is a muscle that lies in a bony canal just superior to the pharyngotympanic tube. It originates from the cartilaginous portion of the pharyngotympanic tube, the bony canal in which it sits, and the greater wing of the sphenoid bone. It inserts into the upper part of the handle of the malleus. When contracted, it pulls the handle of the malleus medially. This action increases the tension across the tympanic membrane, reducing the magnitude of vibrations transmitted into the middle ear. This dampens loud noises or noises produced by chewing. Tensor tympani is innervated through the nerve to tensor tympani, which arises from the mandibular nerve.Other options:- The vestibulocochlear nerve is the eighth cranial nerve. This nerve has two components, a vestibular division that carries balance information, and a cochlear division that carries hearing information.- The glossopharyngeal nerve is the ninth cranial nerve. It has a wide range of functions. It carries taste and sensation from the posterior third of the tongue, as well as sensation from the pharyngeal wall and tonsils, the middle ear, external auditory canal and auricle. It carries parasympathetic fibres that supply the parotid gland. It also supplies the baroreceptors and chemoreceptors of the carotid sinus and supplies the secretomotor fibres to the parotid gland.- The maxillary nerve carries only sensory fibres.- The facial nerve is the seventh cranial nerve. It supplies the muscles of facial expression, as well as stylohyoid, the posterior belly of digastric, and stapedius (the only other muscle associated with the middle ear). It carries taste from the anterior two-thirds of the tongue and sensation from part of the external acoustic meatus, parts of the auricle and the retro-auricular area. It provides secretomotor fibres which supply to the submandibular gland, sublingual gland (via chorda tympani nerve), nasal glands and lacrimal glands.

Erythema nodosum (EN) is an acute, nodular, erythematous eruption that usually is limited to the extensor aspects of the lower legs. It is a delayed hypersensitivity reaction to a variety of antigens| circulating immune complexes have not been found in idiopathic or uncomplicated cases but may be demonstrated in patients with inflammatory bowel disease.Currently, the most common cause of erythema nodosum is a streptococcal infection in children and streptococcal infection and sarcoidosis in adultsIn most patients, erythema nodosum is a self-limited disease and requires only symptomatic relief using nonsteroidal anti-inflammatory drugs (NSAIDs), cool wet compresses, elevation, and bed rest.

Children are able to use a palmar grasp by the age of 6 months and use a pincer grasp by the age of 9 to 10 months. They can sit with support by 6 months and sit without support by 7 to 9 months. They can vocalize by 3 months. Stranger fear appears from 7 to 10 months. So this baby’s development is normal.

Anorexia nervosa is a serious, psychiatric eating disorder characterized by distorted self-image due to which abnormal eating behaviours are adopted. This disorder affects multiple bodily systems, including the gastrointestinal system. The GI manifestations of anorexia are enlarged salivary glands due to purging behaviour, gastritis, gastroparesis, acute gastric dilatation, superior mesenteric artery syndrome, elevated liver transaminases, which cause hepatocyte apoptosis leading to cirrhosis, and steatosis leading to fatty liver. Hepatosplenomegaly is not a recognized complication of anorexia nervosa.

Absence epilepsy is the most common type of generalized childhood epilepsies. It is mainly idiopathic, but 10-40% of the cases have a positive family history. It is characterized by frequent absence seizures and periods of unconsciousness. The hallmark of absence epilepsy on EEG is the bilaterally synchronous 2–4 Hz spike and wave discharges (SWDs). The average age of onset is around 4-8 years, being more prevalent among girls. Treatment resistance is not common.

Due to malaria’s incubation period being between 7 and 30 days, malaria prophylaxis cannot provide a patient with confirmed protection. Prophylaxis treatment also often fails. The symptoms such as neck stiffness, fever, and vomiting are also consistent with the cerebral malaria diagnosis.

Administration of IV prostaglandin/PGE1 (e.g., alprostadil) is indicated in ductal-dependent CHDs until surgery can be performedMechanism: prostaglandin prevents the ductus arteriosus from closing → creates intentional shunt to allow mixing of deoxygenated with oxygenated blood.

Retinopathy of prematurity affects infants born early, and is due to the abnormal growth of retinal vasculature as opposed to vascular occlusion often see in adults. Though most babies with ROP can see normally, the most significant complication of ROP Is retinal detachment which can lead to blindness. Other structures in the eye such as the optic nerve or the fovea however, are not affected. Children may develop nystagmus as a result of poor sight in the affected eye(s).

Henoch–Schönlein purpura (HSP), also known as IgA vasculitis, is a disease of the skin, mucous membranes, and sometimes other organs that most commonly affects children. In the skin, the disease causes palpable purpura (small, raised areas of bleeding underneath the skin), often with joint pain and abdominal pain. It is an acute immunoglobulin A (IgA)–mediated disorder. The tetrad of purpura, arthritis, kidney inflammation, and abdominal pain is often observed.

Umbilical hernias are common in young children and they carry a low risk of incarceration as compared to inguinal hernias. About 90% umbilical hernias resolve by the age of 4 years. The best management for young children is to wait for resolution without surgical repair, unless there are complications. Parents should be assured that the child does not need to be referred to the general surgeon, nor should any home remedies such as taping a coin over the hernia be encouraged. If after the age of 4 it has not resolved, then surgery is indicated. This also applies to girls to prevent an unsightly hernia should she get pregnant.

The average amount of energy required by a well preterm baby in a thermo-neutral environment is 50/kcal/kg to maintain essential body functions while it takes about 70 kcal/kg/day for optimal growth. It is important to ensure that enough proteins are given per calorie to limit catabolism and promote cell building. Caloric need usually increases when the baby is ill.

Lung buds are formed by 4-5 weeks of gestation.Development of the respiratory tract has five stages:- Embryonic (at 4 – 5 weeks of gestation):Formation of lung buds, trachea and mainstem bronchi occur. These structures are formed from a ventral outpouching of foregut pharynx. At this stage, the beginnings of the five lung lobes are present.- Pseudoglandular (at 5 – 16 weeks of gestation):Formation of terminal bronchioles, cartilage and smooth muscles occur in this stage. Adult numbers of airways proximal to acini are in place.- Canalicular (at 16-24 weeks gestation): Differentiation of type I and II epithelial cells can be done in this stage. There is also an increase in the size of proximal airways).- Saccular (at 24 – 40 weeks of gestation): Terminal saccule formation occurs. Production of surfactant takes place at this stage with an increase in the number of goblet cellsUp to half the adult number of alveoli are in place by this stage.- Alveolar (occurs between 32 weeks of gestation till the post-natal age 8): Formation of alveoli and septation occurs with the expansion of air spaces.

The property described in the question is heterogeneity.Heterogeneity is when a single phenotype or genetic disorder can be caused by multiple numbers of genetic mutations.Other options:- Pleiotropy occurs when a single gene influences multiple phenotypic traits. The underlying mechanism is that the gene codes for a product that is used by various cells. A classic example of pleiotropy is the human disease PKU (phenylketonuria).- The penetrance of a disease-causing mutation is the proportion of individuals with the mutation who exhibit clinical symptoms. For example, the gene responsible for a particular autosomal dominant disorder has 70% penetrance, then 70% of those with the mutation will develop the disease, while 30% will not.

Among the given options, psoriasis is not associated with hypertrichosis.The causes of hypertrichosis include:- Drugs: minoxidil, ciclosporin, and diazoxide.- Congenital hypertrichosis lanuginosa and congenital hypertrichosis terminalis.- Porphyria cutanea tarda- Anorexia nervosa