Dominant mutation causes neurological disorder with ichthyotic keratoderma, spasticity, hypomyelination and dysmorphic features.

Background: Ichthyosis and neurological involvement occur in relatively few known Mendelian disorders caused by mutations in genes relevant both for epidermis and neural function.

Objectives: To identify the cause of a similar phenotype of ichthyotic keratoderma, spasticity, mild hypomyelination (on MRI) and dysmorphic features (IKSHD) observed in two unrelated paediatric probands without family history of disease.

Methods: Whole exome sequencing was performed in both patients.

Audio profiles in mitochondrial deafness m.1555A>G and m.3243A>G show distinct differences.

Background: Hearing loss is one of the most common symptoms of mitochondrial disorders. However, audiological phenotypes associated with different molecular defects in mtDNA are not yet well characterized.

Material And Methods: A large cohort of 1499 nonconsanguineous patients aged 5-40 years with hearing loss of unknown etiology was screened for mutations in mtDNA.

Application of array comparative genomic hybridization in 256 patients with developmental delay or intellectual disability.

We used whole-genome exon-targeted oligonucleotide array comparative genomic hybridization (array CGH) in a cohort of 256 patients with developmental delay (DD)/intellectual disability (ID) with or without dysmorphic features, additional neurodevelopmental abnormalities, and/or congenital malformations. In 69 patients, we identified 84 non-polymorphic copy-number variants, among which 41 are known to be clinically relevant, including two recently described deletions, 4q21.21q21.

Postlingual hearing loss as a mitochondrial 3243A>G mutation phenotype.

Background: The prevalence of isolated hearing loss (HL) associated with the m.3243A>G mutation is unknown. The aim of this study was to assess the frequency and heteroplasmy level of the m.

MTHFR 677T is a strong determinant of the degree of hearing loss among Polish males with postlingual sensorineural hearing impairment.

Hearing impairment (HI) is the most common sensory handicap. Congenital HI often has a genetic basis, whereas the etiology of nonsyndromic postlingual HI (npHI) usually remains unidentified. Our purpose was to test whether the MTHFR C677T (rs1801133) polymorphism affecting folate metabolism is associated with the occurrence or severity of npHI.

Wolf-Hirschhorn syndrome due to pure and translocation forms of monosomy 4p16.1 → pter.

The aim of this study was to obtain a quantitative definition of Wolf-Hirschhorn syndrome (WHS) through systematic phenotypic analyses in a group of six children with 4p15.32 → pter, 4p15.33 → pter, or 4p16.

Complex balanced translocation t(1;5;7)(p32.1;q14.3;p21.3) and two microdeletions del(1)(p31.1p31.1) and del(7)(p14.1p14.1) in a patient with features of Greig cephalopolysyndactyly and mental retardation.

Complex chromosome rearrangements (CCRs) are rare structural abnormalities that involve at least two chromosomes and more than two breakpoints and are often associated with developmental delay, mental retardation, and congenital anomalies. We report on a de novo, apparently balanced translocation t(1;5;7)(p32.1;q14.

M34T and V37I mutations in GJB2 associated hearing impairment: evidence for pathogenicity and reduced penetrance.

Despite research the role of the M34T and V37I variants of GJB2 in causing hearing impairment (HI) remains controversial. Our purpose was to test a hypothesis that M34T and V37I are pathogenic but have distinct features resulting in a reduced penetrance. We screened for known GJB2/GJB6 mutations 233 Polish consecutive unrelated subjects with non-syndromic, sensorineural HI who were previously found to carry 35delG mutation on one chromosome.

Aldolase B mutations and prevalence of hereditary fructose intolerance in a Polish population.

We studied 28 Polish hereditary fructose intolerant (HFI) patients (26 unrelated) by direct sequencing of the ALDOB coding region/splice sites. Eight different mutations were found including two novel ones (each found in two unrelated individuals): c.250delC (frameshift) and c.

Two familial cases with a lethal gracile bone dysplasia and intrauterine growth retardation.

A number of more or less distinct entities with low birth weight and abnormal radiographic appearances have been identified. We studied two sisters who were unusual because of severe intrauterine growth restriction, absence of growth after birth, decrease of pre- and postnatal spontaneous mobility, and early fatal outcome. The chondro-osseous morphology documented a distinctive osteochondrodysplasia.