Muscular dystrophies and myopathies: the spectrum of mutated genes in the Czech Republic.

Inherited neuromuscular disorder (NMD) is a wide term covering different genetic disorders affecting muscles, nerves, and neuromuscular junctions. Genetic and clinical heterogeneity is the main drawback in a routine gene-by-gene diagnostics. We present Czech NMD patients with a genetic cause identified using targeted next-generation sequencing (NGS) and the spectrum of these causes. Overall 167 unrelated patients presenting NMD falling into categories of muscular dystrophies, congenital muscular dystrophies, congenital myopathies, distal myopathies, and other myopathies were tested by targeted NGS of 42 known NMD-related genes. Pathogenic or probably pathogenic sequence changes were identified in 79 patients (47.3%). In total, 37 novel and 51 known disease-causing variants were detected in 23 genes. In addition, variants of uncertain significance were suspected in 7 cases (4.2%), and in 81 cases (48.5%) sequence changes associated with NMD were not found. Our results strongly indicate that for molecular diagnostics of heterogeneous disorders such as NMDs, targeted panel testing has a high-clinical yield and should therefore be the preferred first-tier approach. Further, we show that in the genetic diagnostic practice of NMDs, it is necessary to take into account different types of inheritance including the occurrence of an autosomal recessive disorder in two generations of one family.

[Clinical Findings in Family with Aniridia due the PAX6 Mutation]. / Klinické nálezy u clenu rodiny s výskytem izolované aniridie v dusledku PAX6 mutace.

BACKGROUND: inborn isolated aniridia is rare bilateral impairment of several eye structures manifesting mainly by absence of iris, photophobia and decreased visual acuity. There are also others ocular symptoms associated with aniridia such as nystagmus, strabismus, eyelid ptosis, amblyopia, serious refractive errors, anisometropia, corneal changes, impairment of the lens, chamber angle dysgenesis, optic nerve and macular hypoplasia and congenital or secondary glaucoma. The most frequent aetiology of this eye dysgenesis is mutation in PAX6. Aim of this report is to describe ocular findings in the family with familial aniridia (MIM #106210), to debate their severity, prognosis and therapy options. MATERIAL AND METHODS: assessment of previous medical history and actual ophthalmological findings in 4 persons of 3 generation family with aniridia. According to the compliance, the patients underwent these tests: assessment of the visual acuity, intraocular pressure, refraction test, slit-lamp examination and biomicroscopy, pachymetry test and OCT examination. The genetic counselling was performed with subsequent PAX6 mutation analysis. RESULTS: all of the examined aniridia family members showed severe symptoms of the disease, the aniridia and photophobia were present. Positive age related correlation showed progressive visual acuity decrease to the practical blindness due to aniridia-associated keratopathy, secondary glaucoma and cataract. DNA analysis revealed presence of p.Gln180X PAX6 mutation in all of the affected persons. The mutation leads to shortened and therefore non-functional protein. CONCLUSIONS: PAX6 mutations leading to premature termination of protein translation are frequently associated with severe symptoms of aniridia and small intrafamilial variability of ocular impairment. This fact is also well demonstrated in members of family described by this report, the symptoms are severe and progressing with age. Therapy is difficult and often with partial success, such in case of secondary glaucoma in young girl from this family. Any eye surgery must be individually judged due to risk of several post-operative complications. And more, the poor vision in aniridia patients is progressively worsening in time to practical blindness.Key words: aniridia, PAX6, macular hypoplasia, glaucoma.