Riley-Day syndrome

What is Riley-Day syndrome?

Riley-Day syndrome is a nervous system disorder affects both sensory and autonomic nervous system of the body. This is an inherited condition and hereditary transmission is involved.

Riley-Day syndrome is an inborn nervous system dysfunction disorder and steadily progressive with increasing of the age of the affected children. At the time of birth, no classic dysmorphism is present but gradually characteristic facial expression develop. Abnormal genetic mutation involves in the development of the condition.

Riley-Day syndrome alternative known as Familial dysautonomia, HSAN III¹

Symptoms

Some of the classic characteristics of Riley-Day syndrome are:

• Severe kyphoscoliosis means combination of abnormal outward and lateral curvature of the spine.
• Short physique
• Crying without tears, but with an emotional expression is a typical distinctiveness of the Riley-Day syndrome. But usually it is noticeable after seven month of the affected child.
• Autonomic nervous system controls several involuntary functioning of the body, including blood pressure management, regulating heart rate, perspiration secretion, sense organ activity management, emptying of bowel and bladder and digestion. Therefore hampering of the autonomic nervous system functioning provides several difficulties and disorders.
• Feeding difficulty because of gastrointestinal dysmotility.
• Dysautonomic crises” related symptoms, like lack of coordination in oropharyngeal functionality, abnormality in peristalsis in the esophagus, inconsistent gastric emptying, vomiting attacks, erratic reflux of gastro-esophagus. These symptoms are prominent after 3 years of the affected child.
• Chronic lung disease, which can cause aspiration problem
• Restrictive lung disease, which often causes holding of breathing and resulting of that leads to fainting
• Weak muscle
• Retarded growth
• Failure to response pain sensation or difference of temperature
• Diarrhea or constipation
• Uncoordinated movement
• Convulsion
• Decreased taste sensation due to smooth and pale tongue surface ^2,3

Causes

Inherited transmission of Riley-Day syndrome causes the familial history of the condition. In this condition, the child receives a pair of the defective gene from each parent and develop the Riley-Day syndrome. The involve genetic mutation occurs in IKBKAP gene present on the long arm (q) of the chromosome 9 (9q31).

The Riley-day syndrome is rare type of genetic problem mainly occur in Eastern European people, especially Ashkenazi Jews^3,4.

Diagnosis

The diagnosis of the Riley-Day syndrome is based upon estimation of dysfunction of sensory and autonomic nervous system. The following findings during physical examination are indicative in Riley-Day syndrome:

• Absence or reduction of deep tendon reflex action.
• Absence of tear secretion
• Hypotonia or Reduced muscular tone
• Chronic, episodic hypertensive attacks
• Abnormal findings of histamine test, in which receiving of histamine injection does not create any skin redness or swelling.
• Absence of fungiform papillae on the tongue
• severe lateral curvature of the spine (scoliosis)
• Depressed deep tendon reflexes which can be examine through knee jerk or ankle jerk tests
• Certain eye drops causes reduction of the pupil size

Apart from the above mentioned physical findings, specific blood tests are available for IKBKAP genetic evaluation^3,4.

Treatment

There is no curative treatment available for Riley-Day Syndrome. The different treatment is provided to relieve the symptoms. Because of clinical presentation varies from patient to patient, therefore customized therapeutic approaches are applied to the patients depending upon their clinical presentation.

• Anticonvulsive drugs are provided to prevent seizure attacks.
• Postural adjustment and proper diet plan like textured formula feeding at upright position can be preventive for gastro-esophageal reflux.
• Postural hypotension can be prevented by fluid intake enhancement, sufficient salt and caffeine intake or elastic stockings wearing while prolonged standing .
• Anti-emetic drugs are prescribed to control vomiting
• Certain eye drops are given to prevent eye dryness
• Depending upon the respiratory symptoms treatment offers to control the worsen of the condition
• Medications and therapy are applied to treat aspiration pneumonia
• Nutritional supplements can be require to improve growth
• Spinal fusion or surgical intervention require for correction of abnormal spine curvature^3,4.

Complications Related

Riley-Day Syndrome affected individuals have the possibility to develop following complications, like

• Face and Trunk can have blotching or spots
• Excessive perspiration
• Hypertension (Blood pressure more than the normal limit)
• Tachycardia (Increased heart rate)
• Insomnia or sleep disturbances
• Nausea and vomiting
• Irritability
• Difficulty in swallowing
• Drooling (saliva secretes out from mouth)
• Muscle tone worsening⁴

Prognosis

The early diagnosis and immediate commencement of treatment at the early stage of Riley-Day Syndrome can improve survival rate by controlling the symptoms and preventing complication. The possibility of survival till 30 years age of the effected child is 1 in 2⁴.

Preventivon

In Riley-Day syndrome can be prevented by detecting the carrier of the gene, who are responsible for Riley-Day syndrome transmission. Genetic DNA testing is available for detecting Riley-Day syndrome. However, this testing is also applicable for prenatal diagnosis.

Eastern European Jewish people or people with family history of Riley-Day syndrome have greater risk for developing Riley-Day syndrome, therefore genetic counseling is highly recommended for them, before they do family planning^3,4.

References

1. Kita K. [Riley-Day syndrome (familial dysautonomia)]. Nihon Rinsho. 1992 Apr;50(4):846-51. Retrieve from https://www.ncbi.nlm.nih.gov/pubmed/1619769
2. Familial dysautonomia. Retrieve from http://www.orpha.net/consor/cgi-bin/Disease_Search.php?lng=EN&data_id=474&Disease_Disease_Search_diseaseType=ORPHA&Disease_Disease_Search_diseaseGroup=1764&Disease(s)/group%20of%20diseases=Riley-Day-syndrome&title=Riley-Day-syndrome&search=Disease_Search_Simple3
3. Familial dysautonomia. MedlinePlus. Retrieve from https://medlineplus.gov/ency/article/001387.htm
4. Riley-Day Syndrome. Health Guide. . Publised on Wednesday, May 3, 2017. Retrieve from http://www.nytimes.com/health/guides/disease/riley-day-syndrome/overview.html