Heterozygosity for loss-of-function variants in LZTR1 is associated with isolated multiple café-au-lait macules.

Purpose: Pathogenic LZTR1 variants cause schwannomatosis and dominant/recessive Noonan syndrome (NS). We aim to establish an association between heterozygous loss-of-function LZTR1 alleles and isolated multiple café-au-lait macules (CaLMs).

Methods: A total of 849 unrelated participants with multiple CaLMs, lacking pathogenic/likely pathogenic NF1 and SPRED1 variants, underwent RASopathy gene panel sequencing.

Prenatal ultrasound detection of collodion membrane in association with an autosomal recessive congenital ichthyosis due to transglutaminase 1 deficiency.

We describe a case of collodion baby diagnosed prenatally by ultrasound. Classic signs (ectropion, flattened nose, and eclabion) were detected on routine ultrasound at 21 weeks of gestation. At birth, the presence of collodion membrane was confirmed and subsequently, the diagnosis of an autosomal recessive congenital ichthyosis due to compound heterozygosity of the TGM1 gene was made.

Recessive mutations in MSTO1 cause mitochondrial dynamics impairment, leading to myopathy and ataxia.

We report here the first families carrying recessive variants in the MSTO1 gene: compound heterozygous mutations were identified in two sisters and in an unrelated singleton case, who presented a multisystem complex phenotype mainly characterized by myopathy and cerebellar ataxia. Human MSTO1 is a poorly studied protein, suggested to have mitochondrial localization and to regulate morphology and distribution of mitochondria. As for other mutations affecting genes involved in mitochondrial dynamics, no biochemical defects typical of mitochondrial disorders were reported.

Clinical and genetic study of a family with a paternally inherited 15q11-q13 duplication.

Interstitial chromosome 15q11-q13 duplications are associated with developmental delay, behavioral problems and additional manifestations, including epilepsy. In most affected individuals the duplicated chromosome is maternally derived, whereas paternal inheritance is more often associated with a normal phenotype. Seizures have not been described in patients with paternal dup 15q11-q13.

Molecular mechanisms generating and stabilizing terminal 22q13 deletions in 44 subjects with Phelan/McDermid syndrome.

In this study, we used deletions at 22q13, which represent a substantial source of human pathology (Phelan/McDermid syndrome), as a model for investigating the molecular mechanisms of terminal deletions that are currently poorly understood. We characterized at the molecular level the genomic rearrangement in 44 unrelated patients with 22q13 monosomy resulting from simple terminal deletions (72%), ring chromosomes (14%), and unbalanced translocations (7%). We also discovered interstitial deletions between 17-74 kb in 9% of the patients.

GPR143 mutational analysis in two Italian families with X-linked ocular albinism.

X-linked ocular albinism type 1 (OA1) is caused by mutations in G protein-coupled receptor 143 (GPR143) gene, which encodes a membrane glycoprotein localized to melanosomes. GPR143 mainly affects pigment production in the eye, resulting in optic changes associated with albinism, including hypopigmentation of the retina, nystagmus, strabismus, foveal hypoplasia, abnormal crossing of the optic fibers, and reduced visual acuity. We report the mutational analysis of the GPR143 gene on two unrelated families with OA1 using direct sequencing and real-time quantitative polymerase chain reaction.