epicanthic folds

Immunodeficiency-Centromeric Instability-Facial Anomalies Syndrome 3

Clinical Characteristics
Ocular Features: 

Patients have been described as having variable oculofacial features including epicanthal folds, hypertelorism, strabismus, and 'tapetoretinal degeneration'.    

Systemic Features: 

The full phenotype is variable and unknown based on the 5 reported patients from 4 families of whom 3 were consanguineous.  Recurrent infections (especially respiratory and otitis media) seem to be among the most consistent features.  Others include intrauterine growth retardation, developmental delay including psychomotor delays, a flat midface with various anomalies, low-set ears, renal dysgenesis, polydactyly, severe agammaglobulinemia, hypospadias, and cryptorchidism.  Normal T-cell function and normal B cells are present.  Conductive hearing loss, polydactyly, and scoliosis may be features as well.  Two of the 5 reported patients with ICF3 were reported to have mental retardation.  One patient died at the age of 26 years.

Genetics

Homozygosity of CDCA7 (2q31.1) mutations with centromeric instability and hypomethylation of selected juxtacentromeric heterochromatin regions is responsible for this (ICF3) autosomal recessive condition.  There is genetic heterogeneity in ICF (ICF1, ICF2, ICF3, and ICF4 [see 242860).   

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No effective treatment has been reported.

References
Article Title: 

Mutations in CDCA7 and HELLS cause immunodeficiency-centromeric instability-facial anomalies syndrome

Thijssen PE, Ito Y, Grillo G, Wang J, Velasco G, Nitta H, Unoki M, Yoshihara M, Suyama M, Sun Y, Lemmers RJ, de Greef JC, Gennery A, Picco P, Kloeckener-Gruissem B, Gungor T, Reisli I, Picard C, Kebaili K, Roquelaure B, Iwai T, Kondo I, Kubota T, van Ostaijen-Ten Dam MM, van Tol MJ, Weemaes C, Francastel C, van der Maarel SM, Sasaki H. Mutations in CDCA7 and HELLS cause immunodeficiency-centromeric instability-facial anomalies syndrome. Nat Commun. 2015 Jul 28;6:7870.

PubMed ID: 
26216346

Noonan Syndrome

Clinical Characteristics
Ocular Features: 

Noonan syndrome has prominent anomalies of the periocular structures including downward-slanting lid fissures, hypertelorism, epicanthal folds, high upper eyelid crease, and some limitation of ocular mobility most commonly of the levator.  Ptosis and strabismus are present in nearly half of patients. Amblyopia has been found in one-third of patients and almost 10% have nystagmus.  Corneal nerves are prominent and a substantial number of individuals have optic nerve abnormalities including drusen, hypoplasia, colobomas and myelinated nerves.  Evidence of an anterior stromal dystrophy, cataracts, or panuveitis is seen in a minority of patients.  About 95% of patients have some ocular abnormalities.

Systemic Features: 

Patients are short in stature.  Birth weight and length may be normal but lymphedema is often present in newborns.  The neck is usually webbed (pterygium colli) and the ears low-set.  The sternum may be deformed.  Cardiac anomalies such as coarctation of the aorta, pulmonary valve stenosis, hypertrophic cardiomyopathy, and septal defects are present in more than half of patients.  Dysplasia of the pulmonic valve has been reported as well.  Thrombocytopenia and abnormal platelet function with abnormalities of coagulation factors are found in about 50% of cases resulting in easy bruising and prolonged bleeding.  Cryptorchidism is common in males.  Some patients have intellectual disabilities with speech and language problems.  Most have normal intelligence.   

Parents of affected children often have subtle signs of Noonan Syndrome.

Genetics

This is an autosomal dominant disorder that can result from mutations in at least 7 genes.  Nearly half are caused by mutations in the PTPN11 gene (12q24.1) (163950).  Mutations in the SOS1 gene (2p22-p21) cause NS4 (610733) and account for 10-20% of cases, those in the RAF1 gene (3p25) causing NS5 (611553) for about the same proportion, and mutations in the KRAS gene (12p12.1) (NS3; 609942) cause about 1%.  Mutations in BRAF (7q34) causing NS7 (613706), NRAS (1p13.2) responsible for NS6 (613224), and MEK1 genes have also been implicated and it is likely that more mutations will be found.  The phenotype is similar in all individuals but with some variation in the frequency and severity of specific features.  New mutations are common. 

Several families suggestive of autosomal recessive inheritance (NS2) (605275) have been reported but no homozygous genotype has been identified.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

There is no treatment for most of the developmental problems but some patients benefit from special education. Cardiac surgery may be required in some cases to correct the developmental defects.  Bleeding problems can be treated with supplementation of the defective coagulation factor.  Growth hormone therapy can increase the growth velocity.

References
Article Title: 

Update on turner and noonan syndromes

Chacko E, Graber E, Regelmann MO, Wallach E, Costin G, Rapaport R. Update on turner and noonan syndromes. Endocrinol Metab Clin North Am. 2012 Dec;41(4):713-34. Epub 2012 Sep 28.

PubMed ID: 
23099266
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