Patients with King syndrome present in childhood, although the disease is seen from birth. The first cases reported were in males, who are more frequently affected than females. Currently, diagnostic criteria for the disease are vague. King syndrome (KS) was thought to be sporadic, but a genetic component has been suggested, with a possible autosomal dominant inheritance pattern [1]. KS shares many features with Noonan syndrome, however, the relationship between the two diseases has yet to be established [2] [3]. Despite similarities in clinical presentation, symptoms classically associated with Noonan syndrome, including coagulopathy, lymphatic swelling of the extremities, and wide spaced eyes, are not seen in patients with KS. It is unclear whether or not KS is a unique disorder, but it may be the common manifestation of several congenital myopathies [4] [5].

Relatives of the affected individuals have been found to have skeletal abnormalities or raised creatinine phosphokinase (CPK) levels [2]. Many with KS are diagnosed with malignant hyperthermia as the first sign of KS, which then prompts further investigation, although the malignant hyperthermia is sometimes fatal.

KS is a progressive condition and is characterized by worsening myopathy which may first appear as developmental delay in the motor domain, kyphosis, scoliosis, winged scapula and weak tendon reflexes [4]. There may be other skeletal deformities in the lumbar and thoracic spine as well as the chest wall, such as pectus carinatum. In addition, KS patients often have a short stature.

Other features associated with KS include low-set ears, webbed neck, crowding and misalignment of teeth, drooping eyelids, undescended testes, down-slanting palpebral fissures and an underdeveloped lower jaw [6]. Cleft palate and high arched palate have been reported [2]. KS has not been linked to intellectual disability.

• Fever

  Anaesthetised patients may develop high fever and muscle rigidity with rhabdomyolysis, release of myoglobin, renal damage and acute renal failure. [medical-dictionary.thefreedictionary.com]

  Categories: This disease is grouped under: The King-Denborough syndrome (KDS) is a congenital myopathy associated with susceptibility to malignant hyperthermia, skeletal abnormalities and dysmorphic features with characteristic facial appearance. 0003236 Fever [rarediseases.info.nih.gov]

• Camping

  Brendan is at sleep-away camp this week and couldn’t be reached for comment. [newsday.com]

  We can see the difference in the teens and young adults who attend our camps and workshops. They are truly becoming citizens of the world – with broad interests and skills that were once not considered possible for those with Williams syndrome. [williams-syndrome.org]

• Normal Stature

  Unlike other reported cases, our patient had hyperextensible joints, normal stature, and pectus excavatum. The cardiac ventricles, aorta, and pulmonary artery were dilated. [ncbi.nlm.nih.gov]

• Hyperextensible Joints

  Unlike other reported cases, our patient had hyperextensible joints, normal stature, and pectus excavatum. The cardiac ventricles, aorta, and pulmonary artery were dilated. [ncbi.nlm.nih.gov]

• Indecisiveness

  But then Rowling's story mires itself in page after page of indecision. Watching this yarn trying to find its way is like feeling a mix of distaste and pity at seeing eight tentacles flop around in search of a brain. [theage.com.au]

• Forgetful

  She always reached heights that we didn't know she would be able to," her mother said By Pei-Sze Cheng NEWSLETTERS Receive the latest local updates in your inbox Students at Huntington High School made sure that a couple with Down Syndrome would never forget [nbcnewyork.com]

  'I'm not going to forget it as long as I live.' Lakeia said that 'literally the whole' school voted for Donald after a few of his peers began campaigning for him to be homecoming king. [dailymail.co.uk]

  "I’ll never forget: One time, I said to one of his friends that I was hoping she could make it to his birthday party,” Diane continued, “and she said, ‘Oh, I’ll always come for Tyler,’ and to know that my child is that loved — that just meant so much [eu.desmoinesregister.com]

  Now, these are the six manifestations of the King Baby Syndrome; * The King *the Princess *the Ego Tripper *the Falsely Humble *the Perfectionist & *the Clinging Vine King Baby, you see, has a tendency to remember his wife's vows and forget his own! [beroenden.ifokus.se]

• Waddling Gait

  There was a generalized reduction in muscle mass with proximal limb weakness, short stature, diminished deep tendon reflexes, and an awkward waddling gait. [patientcareonline.com]

• Cryptorchidism

  In 1973, King described a subgroup of malignant hyperthermia patients with slowly progressive myopathy, short stature, kyphoscoliosis, pectus carinatum, cryptorchidism, and a characteristic facial appearance. [ncbi.nlm.nih.gov]

  Considering the severity and the high rate of lethality of a MH reaction, as children with KDS are likely to undergo surgery with general anes- thesia for cryptorchidism and skeletal deformities, a preoperative diagnosis should be recognized. [idocslide.com]

  […] abnormalities (e.g. short stature, scoliosis, kyphosis, lumbar lordosis and pectus carinatum/excavatum), mild dysmorphic facial features (e.g. hypertelorism, down-slanting palpebral fissures, epicanthic folds, low set ears, micrognathia), webbing of the neck, cryptorchidism [ebi.ac.uk]

  We report a case of King's syndrome without the cryptorchidism and pectus carinatum associated with the syndrome. King's syndrome's possible link to Noonan's syndrome is discussed herein, and the diagnosis and management of MH are briefly reviewed. [jamanetwork.com]

Apart from the assessment of clinical features, there are no specific diagnostic tests for King syndrome. Despite the known characteristic features, it is still difficult to correctly identify KS. Patients in whom KS is suspected may be further investigated before exposure to anesthetic agents occurs. The available exams include:

• Muscle biopsy: Microscopic examination of muscle may reveal a range of abnormalities, including a change in the size of muscle fibers, a large number of small-sized type 1 fibers and muscle atrophy [3].
• Tests for malignant hyperthermia (MH) susceptibility: These include the European Malignant Hyperthermia Group (EMHG) and the North American Malignant Hyperthermia Group (NAMHG) protocols. These are routinely carried out and both have high specificity for MH [7] [8] [9].
• Creatinine phosphokinase: Elevated levels may be found in patients as well as their relatives [10].

1. Johns Hopkins University. Malignant hyperthermia, susceptibility to, 1; MHS1. Online Mendelian Inheritance in Man (OMIM). http://omim.org/entry/145600. Published July 3, 2013. Accessed May 24, 2017.
2. Graham GE, Silver K, Arlet V, Der Kaloustian VM. King syndrome: further clinical variability and review of the literature. Am J Med Genet. 1998;78(3):254-259.
3. Reed UC, Resende MBD, Ferreira LG, et al. King-Denborough Syndrome: report of two Brazilian cases. Arq Neuropsiquiatr. 2002;60(3B):739-741.
4. Chitayat D, Hodgkinson KA, Ginsburg O, Dimmick J, Watters GV. King syndrome: a genetically heterogenous phenotype due to congenital myopathies. Am J Med Genet. 1992;43(6):954-956.
5. Habib AS, Millar S, Deballi P, Muir HA. Anesthetic management of a ventilator-dependent parturient with the King-Denborough syndrome. Can J Anesth. 2003;50(6):589-592.
6. Maharaj R, Osborne IJS. The King-Denborough syndrome in the paediatric patient. SAJAA. 2007;13(2):27-30.
7. The European Malignant Hyperpyrexia Group. A protocol for the investigation of malignant hyperpyrexia (MH) susceptibility. Br J Anaesth. 1984;56(11):1267–1269.
8. Larach MG. Standardization of the caffeine halothane muscle contracture test. North American Malignant Hyperthermia Group. Anesth Analg. 1989;69(4):511–515.
9. Islander G, Twetman ER. Comparison between the European and North American protocols for diagnosis of malignant hyperthermia susceptibility in humans. Anesth Analg. 1999;88(5):1155-1160.
10. Isaacs H, Barlow MB. The genetic background to malignant hyperpyrexia revealed by serum creatinine phosphokinase estimations in asymptomatic relatives. Br J Anaesth. 1970;42(12):1077-1084.