Alessandra Orsi

Novel PTEN mutations in neurodevelopmental disorders and macrocephaly.

Somatic mutations of the phosphatase and tensin (PTEN) gene have been frequently detected in many types of human cancer. However, germline mutations can determine multiple hamartoma syndromes and, as more recently ascertained, syndromes clinically characterized by autism associated with macrocephaly. To determine whether germline mutations of PTEN may lead to different phenotypes, we screened all the nine exons of the PTEN gene in 40 patients with neurodevelopmental disorders, with or without features of autism spectrum disorder, associated with macrocephaly. Three novel de novo missense mutations were found (p.H118P, p.Y176C, p.N276S) in two severely mentally retarded patients with autism and in a subject with neurodevelopmental disorders without autistic features. Our results provide evidence that PTEN germline mutations may sustain a more wide phenotypical spectrum than previously suggested.

Delineation of the phenotype associated with 7q36.1q36.2 deletion: Long QT syndrome, renal hypoplasia and mental retardation†

Terminal deletions of the long arm of chromosome 7 are well known and are frequently associated with hypotelorism or holoprosencephaly due to the involvement of the SHH gene located in 7q36.3. These deletions are easily detectable with routine subtelomeric MLPA analysis. Deletions affecting a more proximal part of 7q36, namely bands 7q36.1q36.2 are less common, and may be missed by subtelomeric MLPA analysis. We report a 9‐year‐old girl with a 5.27 Mb deletion in 7q36.1q36.2, and compare her to literature patients proposing a phenotype characterized by mental retardation, unusual facial features, renal hypoplasia and long QT syndrome due to loss of the KCNH2 gene. These characteristics are sufficiently distinct that the syndrome may be diagnosed on clinical grounds.

Neurocutaneous syndrome with mental delay, autism, blockage in intracellular vescicular trafficking and melanosome defects

We evaluated a 11‐year‐old male patient with mental delay, autism and brownish and whitish skin spots. The former resembled those of neurofibromatosis, the latter those of tuberous sclerosis. The patient received a complete clinical work‐up to exclude neurofibromatosis, tuberous sclerosis, or any other known neurocutaneous disease, with biochemistry, chromosome analysis and analysis of skin specimens. Being all the other tests not significant, two main ultrastructural defects were observed. The first was a blockage in intracellular vescicular trafficking with sparing of the mitochondria; the second an aberrant presence of melanosomes in vacuoles of several cell lines and abnormal transfer of these organelles to keratinocytes. This patient presented with a unique clinical picture distinct from neurofibromatosis or tuberous sclerosis or any other known neurocutaneous disease. The ultrastructural abnormalities suggested a defect in cell trafficking involving several cell lines and compartments.

Polydactyly With Ectodermal Defect, Osteopenia, and Mental Delay

Five members from 3 generations, including a 35-year-old woman and her 2 sons, both mentally impaired to a different degree, were studied in a tertiary care hospital. Anamnestic, clinical, neurological, and radiological evaluations were used to describe phenotypes. A and B postaxial polydactyly, transmitted likely as autosomal dominant, was associated with an extensive variability of phenotypic features: (1) cutaneous syndactyly, (2) nail–teeth dysplasia, (3) osteopenia, and (4) mental delay. The likelihood that the constellation of observations we report here is caused by mutation of a single gene that subsequently affects multiple physiological activities, although fascinating, remains to be proven. Instead, we hypothesize that it likely develops as a contiguous gene syndrome.

Additional case of Marden-Walker syndrome : support for the autosomal-recessive inheritance and refinement of phenotype in a surviving patient

In this report, we present a 14-year-old girl, born to consanguineous parents, who presented with severe mental retardation, hypotonia, short stature, and congenital joint contractures. The craniofacial features were scaphocephaly, thin/long and immobile face, marked hypoplasia of the midface, temporal narrowness, blepharophimosis, palpebral ptosis, and strabismus. The combination of such a distinctive craniofacial appearance and psychomotor retardation allows us to recognize a new case of the Marden-Walker syndrome. Our patient represents one of the rare cases in which consanguineous mating supports the autosomal-recessive pattern of inheritance of this condition. Furthermore, through refining the phenotype of a surviving patient, this report may contribute to a better recognition of this disorder in older affected children. (J Child Neurol 2001;16:150-153).

Silent increase of urinary ethylmalonic acid is an indicator of nonspecific brain dysfunction.

Our aim was to compare urinary ethylmalonic acid (EMA) levels in subjects who had no apparent clinical reason to have increased levels of this substance but were suffering from non‐specific CNS impairment, and healthy controls. Urinary EMA concentrations detected by 1H‐NMR spectroscopy were studied in 130 subjects with CNS impairment of unknown origin (with no definite diagnosis, no specific symptoms or signs, and normal common biochemical and metabolic screening results) and 130 age‐ and sex‐matched healthy subjects. EMA levels exceeding two standard deviations (SD) above normal (i.e. 8.1 mmol/molCn) were found in a subgroup of CNS‐impaired patients and healthy controls. EMA levels exceeding 2 SD above normal were fourfold prevalent in the urine of patients with non‐specific CNS impairment compared to from the EMA levels in healthy controls. Moreover, we found that the level exceeding > 8.1 mmol/molCn (i.e. > + 2 SD) had sufficient discrimination accuracy in identifying subjects with non‐specific CNS impairment; the level exceeding 12 mmol/molCn (i.e. > + 6 SD) reaches suitable accuracy (i.e. 100% specificity and 78.6% sensitivity). These observations are of importance, as we found that subtle increases in urinary EMA levels are frequent in patients with non‐specific CNS impairment. The reasons for this association remain unknown. Copyright

New neurocutaneous syndrome with defect in cell trafficking and melanosome pathway: The future challenge

OBJECTIVE Case study of a CNS impairment lacking in presumptive cause; case presents with a clinical phenotype encompassing multiple differently expressed and combined symptoms, as well as a subtle skin defect. MATERIALS AND METHODS A 6-year-old male with apparently isolated mental delay, speech delay, attention deficit/hyperactivity disorder, epilepsy, and subtle and insignificant skin dyschromias. The patient underwent a systematic evaluation, including clinical history; medical, neurological and ophthalmologic examinations. Skin, teeth, nails, hair and sudation were examined for defects. Routine laboratory tests for blood, urine, were performed. The proband had thyroid function tests, electrocardiography, genitourinary system and abdominal examinations. Special examinations pertaining to mental performance, biochemistry, chromosome studies, imaging and electrodiagnostic studies, and skin biopsy were also performed. RESULTS Investigators ruled out genetic syndromes, congenital infections, fetal deprivation, perinatal insults, intrauterine exposure to drug abuse, and postnatal events such as CNS infections as possible common causes of brain impairment. Being all further test negative, the patient exhibited an ultrastructural defect of the skin, identical to that previously described [Buoni S, Zannolli R, de Santi MM, Macucci F, Hayek J, Orsi A et al. Neurocutaneous syndrome with mental delay, autism, blockage in intracellular vesicular trafficking and melanosome defects. Eur J Neurol 2006;13:842-51], suggesting that some cell compartments, such as rough endoplasmic reticulum, lysosomes, Golgi apparatus, and the vesicular zone (racket) of Birbeck granules, sharing similar components, can be altered, resulting in a common defect in cell trafficking, associated to melanosome defects. CONCLUSIONS This new devasting, ultrastructural phenotype accompanied by apparently unspecific and mixed neurological symptoms should represent a future challenge to finally discover the pathogenesis of many childhood CNS symptoms, that currently seem to lack any apparent cause.