Two brothers with 22q13 deletion syndrome and features suggestive of the Clark-Baraitser syndrome

Sapienza University of Rome, Roma, Latium, Italy
Clinical Dysmorphology (Impact Factor: 0.42). 08/2005; 14(3):127-32. DOI: 10.1097/00019605-200507000-00004
Source: PubMed

ABSTRACT We report on two brothers with moderate-to-severe mental retardation, severe macrocephaly, obesity, characteristic face, big hands and feet, advanced bone age and brain abnormalities, including frontal cortical atrophy. These two boys resembled the two brothers described by , two maternal cousins subsequently reported by and a Brazilian boy described by . Upon further investigation, we detected a cryptic subtelomeric deletion of chromosome region 22q13, not present in either parent and probably due to a maternal germinal mosaicism. Thus, we describe the first familial case of 22q13 deletion and recommend that patients with a phenotype suggestive of the so-called Clark-Baraitser syndrome be tested for submicroscopic 22qter deletion.

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    ABSTRACT: The 22q13.3 deletion causes a neurodevelopmental syndrome, also known as Phelan-McDermid syndrome (MIM #606232), characterized by developmental delay and severe delay or absence of expressive speech. Two patients with hemizygous chromosome 22q13.3 telomeric deletion were referred to us when brain-imaging studies revealed cerebellar vermis hypoplasia (CBVH). To determine whether developmental abnormalities of the cerebellum are a consistent feature of the 22q13.3 deletion syndrome, we examined brain-imaging studies for 10 unrelated subjects with 22q13 terminal deletion. In seven cases where the availability of DNA and array technology allowed, we mapped deletion boundaries using comparative intensity analysis with single nucleotide polymorphism (SNP) microarrays. Approximate deletion boundaries for three additional cases were derived from clinical or published molecular data. We also examined brain-imaging studies for a patient with an intragenic SHANK3 mutation. We report the first brain-imaging data showing that some patients with 22q13 deletions have severe posterior CBVH, and one individual with a SHANK3 mutation has a normal cerebellum. This genotype-phenotype study suggests that the 22q13 deletion phenotype includes abnormal posterior fossa structures that are unlikely to be attributed to SHANK3 disruption. Other genes in the region, including PLXNB2 and MAPK8IP2, display brain expression patterns and mouse mutant phenotypes critical for proper cerebellar development. Future studies of these genes may elucidate their relationship to 22q13.3 deletion phenotypes. © 2012 Wiley Periodicals, Inc.
    American Journal of Medical Genetics Part A 01/2013; 161A(1). DOI:10.1002/ajmg.a.35700 · 2.05 Impact Factor
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    ABSTRACT: Autism spectrum disorder (ASD) and intellectual disability (ID) can be caused by mutations in a large number of genes. One example is SHANK3 on the terminal end of chromosome 22q. Loss of one functional copy of SHANK3 results in 22q13 deletion syndrome or Phelan-McDermid syndrome (PMS) and causes a monogenic form of ASD and/or ID with a frequency of 0.5% to 2% of cases. SHANK3 is the critical gene in this syndrome, and its loss results in disruption of synaptic function. With chromosomal microarray analyses now a standard of care in the assessment of ASD and developmental delay, and with the emergence of whole exome and whole genome sequencing in this context, identification of PMS in routine clinical settings will increase significantly. However, PMS remains a rare disorder, and the majority of physicians have never seen a case. While there is agreement about core deficits of PMS, there have been no established parameters to guide evaluation and medical monitoring of the syndrome. Evaluations must include a thorough history and physical and dysmorphology examination. Neurological deficits, including the presence of seizures and structural brain abnormalities should be assessed as well as motor deficits. Endocrine, renal, cardiac, and gastrointestinal problems all require assessment and monitoring in addition to the risk of recurring infections, dental and vision problems, and lymphedema. Finally, all patients should have cognitive, behavioral, and ASD evaluations. The objective of this paper is to address this gap in the literature and establish recommendations to assess the medical, genetic, and neurological features of PMS.
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    ABSTRACT: Purpose The 22q13.3 deletion syndrome, also known as Phelan-McDermid Syndrome, is a rare genetic disorder characterized by hypotonia, severely impaired development of speech and language, autistic-like behavior, and minor dysmorphic features. Neurologic problems may include seizures of different types, such as febrile, generalized tonic-clonic, focal, and absence seizures. No peculiar EEG features have been associated with 22q13 deletion syndrome to date. In order to verify if a peculiar clinical and EEG pattern is present in 22q13.3 deletion syndrome, we studied six Italian patients with this chromosome abnormality. Methods Array CGH analysis was carried out in the six subjects (1 male, 5 females, age range 11-30 years, median 19.5). They underwent a complete general and neurologic examinations. The EEG study consisted of at least one awake and one nap–sleep video-EEG recordings and evaluation of other EEGs performed elsewhere. Results Three subjects suffered from myoclonic or generalized tonic-clonic seizures with a rather benign course; all showed multifocal paroxysmal abnormalities on EEG recording, predominant over the frontal-temporal regions, activated during sleep. Conclusion 22q13.3 deletion syndrome seems to be associated, at least in a subgroup of patients, with a peculiar clinical and EEG pattern, characterized by a childhood epilepsy with a rather benign evolution and with multifocal paroxysmal EEG abnormalities activated by sleep.
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