hypohidrosis

HELIX Syndrome

Clinical Characteristics
Ocular Features: 

Alacrimia has been confirmed with Schirmer test strips but the ocular examination has been described as otherwise normal.

Systemic Features: 

All patients have anhidrosis resulting in alacrima and xerostomia with heat intolerance.  Nails and hair are normal.  Muscle weakness, heart palpitations, and post-exertional cramping may be experienced with mild exercise beginning in the first decade.  Polydipsia and polydipsia may be additional complaints.  Severe dental enamel wear is often evident.  The skin has a fine, white scaliness.  Adolescent-onset nephrocalcinosis has been reported in some patients.

The majority of patients have elevated serum Mg++ levels.  Mild renal failure occurs with loss of NaCl and secondary hyperaldosteronism and hypokalemia.

Genetics

Homozygous mutations in the CLDN10 gene (13q32.1) are responsible for this disorder.  Consanguinity is present in some families.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

Dental resins has been reported to be beneficial as a protective coating of the teeth.  Ocular evaluations for corneal damage from alacrima have not been reported but moisturizing preparations should be used as indicated. 

References
Article Title: 

Multiplex epithelium dysfunction due to CLDN10 mutation: the HELIX syndrome

Hadj-Rabia S, Brideau G, Al-Sarraj Y, Maroun RC, Figueres ML, Leclerc-Mercier S, Olinger E, Baron S, Chaussain C, Nochy D, Taha RZ, Knebelmann B, Joshi V, Curmi PA, Kambouris M, Vargas-Poussou R, Bodemer C, Devuyst O, Houillier P, El-Shanti H. Multiplex epithelium dysfunction due to CLDN10 mutation: the HELIX syndrome. Genet Med. 2017 Aug 3. doi: 10.1038/gim.2017.71. [Epub ahead of print].

PubMed ID: 
28771254

Fabry Disease

Clinical Characteristics
Ocular Features: 

Fabry disease is a lysosomal enzyme (alpha-galactosidase A) deficiency resulting in the accumulation of globotriaosylceramide (Gb3) and related glycosphingolipids throughout the body.  The signature ocular manifestation is the whorl-like corneal pattern of lipid (glycosphingolipid) deposits which are present in both hemizygous males and heterozygous females.  These are sometimes referred to as cornea verticillata or Fleischer vortex dystrophy with a pattern similar to that seen in some patients using atabrine or amiodarone.  A general 'haze' throughout the cornea is even more common.  Lens opacities may also be distinctive and generally are one of two types: spoke-like opacities beneath the posterior capsule among males, and wedge-shaped anterior subcapsular deposits, again primarily in males.  The corneal and lens opacities seldom cause significant vision problems.

Involvement of the ocular vessels is present in almost all patients.  A notable increase in tortuosity of conjunctival vessels is present in 97% of hemizygous males and 78% of heterozygous females.  Increased retinal vessel tortuosity is less common but arteriolar involvement significantly increases the risk of central retinal artery occlusions.  An 11 yo Turkish female heterozygote with a cilioretinal artery occlusion and anterior ischemic optic neuropathy in one eye has been reported.

Systemic Features: 

The relatively common occurrence and the protean nature of Fabry disease has lead to its designation by some as the Great Imposter, replacing syphilis to which this term was previously applied.  Compounding the diagnostic difficulties in some individuals is the absence of the complete classical phenotype due to the presence of DNA variants that may modify the expression of some the clinical features.

Most signs present in the first or second decade of life with generally earlier onset in males.  The presence of proteinuria before the age of 20 years in the absence of other primary kidney disease should always raise the possibility of Fabry disease.  However, the diagnosis is often not made until the third decade in males and the fourth decade in females.  Glycosphingolipid inclusion deposits in endothelial cells are responsible for the systemic signs and symptoms including renal and heart disease which are the most common causes of premature death.  Small vessel involvement resulting in cerebrovascular disease and painful peripheral neuropathy can be debilitating. The risk of ischemic strokes is increased.  Cardiac manifestations include hypertrophic cardiomyopathy (60%), mainly involving the left ventricle, and dysfunction of the mitral and aortic valves (10 to 25%).  Dysfunction of renal glomeruli may progress to renal failure by the third to fifth decade in males.  The angiokeratomas and angiomas (most pronounced in a swimming trunk pattern) are secondary to vascular involvement of cutaneous vessels but are non-specific since they also occur in other lysosomal diseases.  The life expectancy of females is reduced by about 5 years and for males about 16 years compared with the general US population.

Involvment of the autonomic system manifests as intermittent fever, hypohidrosis, and poor temperature control.  Some patients have periodic crises of severe pain in the extremities as well as intermittent epigastric pain. Hearing loss and episodic tinnitus are common complaints.

Genetics

This is an X-linked disorder and generally assumed to be recessive although some have suggested dominance since most heterozygous females have significant manifestations that can be life-threatening.  The mutations in the responsible gene (GLA), located at Xq22, involve a variety of deletions, rearrangements and single base pair changes.  Defects in the GLA gene lead to dysfunction of the enzyme alpha-galactosidase A resulting in lysosomal deposition of glycosphingolipids throughout the body, especially in vascular endothelial cells.   

The milder disease and increase in the range of clinical manifestations among females is likely a reflection of variable patterns of X-inactivation.

Increased tortuosity of retinal arterioles is also seen in fucidosis (230000), Williams syndrome (194050), and in a condition known as retinal arteriolar tortuosity (611773, 180000).

Pedigree: 
X-linked dominant, father affected
X-linked dominant, mother affected
Treatment
Treatment Options: 

Enzyme replacement therapy using agalsidase alfa (commercially available as Febrazyme (tm)) have shown promise as measured by renal function, pain intensity, left ventricular size, and general quality of life.  However, the impact on longevity remains to be determined.  Evidence suggests that early treatment is associated with improved outcomes. The corneal and lenticular opacities generally do not require treatment.

Continuous release of cardiac troponin I (cTNI) with elevated serum levels may be a clue to the severity of heart involvement.

References
Article Title: 

Favourable effect of early versus late start of enzyme replacement therapy on plasma globotriaosylsphingosine levels in men with classical Fabry disease

Arends M, Wijburg FA, Wanner C, Vaz FM, van Kuilenburg ABP, Hughes DA, Biegstraaten M, Mehta A, Hollak CEM, Langeveld M. Favourable effect of early versus late start of enzyme replacement therapy on plasma globotriaosylsphingosine levels in men with classical Fabry disease. Mol Genet Metab. 2017 May 4. pii: S1096-7192(17)30156-7.

PubMed ID: 
28495078

Continuous cardiac troponin I release in fabry disease

Feustel A, Hahn A, Schneider C, Sieweke N, Franzen W, Gunduz D, Rolfs A, Tanislav C. Continuous cardiac troponin I release in fabry disease. PLoS One. 2014 Mar 13;9(3):e91757. doi: 10.1371/journal.pone.0091757. eCollection 2014.

PubMed ID: 
24626231

Fabry disease: overall effects of agalsidase alfa treatment

Beck M, Ricci R, Widmer U, Dehout F, de Lorenzo AG, Kampmann C, Linhart A,
Sunder-Plassmann G, Houge G, Ramaswami U, Gal A, Mehta A. Fabry disease: overall effects of agalsidase alfa treatment. Eur J Clin Invest. 2004 Dec;34(12):838-44.

PubMed ID: 
15606727
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