Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026827 (hypotonia)
 5,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied a 25-year-old black woman with healthy parents and her 2-year, 11-month-old son. Her motor development was delayed and she started to walk with support when she was 6 years old. She never walked independently and had always used a wheelchair. Neurological evaluation showed severe weakness and atrophy of her feet, legs, and hands, bilateral pes cavus and hammertoes, corrected scoliosis, hypesthesia for proprioception and vibration sense in both feet and ankles, and areflexia. She had normal intelligence. Her son also had delayed motor milestones and was still unable to stand and walk independently at almost 3 years. Neurological evaluation revealed diffuse muscle hypotonia and weakness with generalized areflexia and normal intelligence. No muscle atrophies or feet deformities were noticed. Nerve conduction velocities showed significant slowing (less than 5 m/s) with prolonged distal latencies (above 30 ms). Compound motor action potential amplitudes were markedly reduced. Electromyography revealed polyphasic motor unit potentials. Molecular genetic studies indicated a Trembler type missense point mutation of exon 4 of the peripheral myelin protein 22 gene that led to the substitution of a spartic acid for glycine in both the mother and her son. Her parents showed normal DNA studies.
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PMID:Dejerine-Sottas neuropathy in mother and son with same point mutation of PMP22 gene. 899 89

Codon 72 has been designated as a hot spot for distinct missense mutations in the peripheral myelin protein 22 (PMP22) gene. Ser72Leu substitution was associated with Dejerine-Sottas syndrome (DSS) in four patients and with congenital hypomyelination neuropathy (CHN) in one patient. Our objective was to report one other DSS patient with Ser72Leu substitution in PMP22 and to concurrently illustrate how less invasive procedures such as skin biopsy could provide a rapid and reliable alternative to conventional sural nerve biopsy for the characterization of histophenotypic features. A skin biopsy was carried out in a 2 4/12-year-old girl with muscle atrophy, hypotonia and weakness, as well as generalized areflexia and absent sensory and motor nerve responses. Standard electron microscope techniques were used. PMP22 was screened by automated direct nucleotide sequencing analysis. Morphological examination revealed basal lamina onion bulbs surrounding a de- or hypomyelinated axon in all nerve bundles. Mutation analysis demonstrated a missense point mutation in codon 72 of the PMP22 gene leading to a Ser72Leu substitution. Further genotype-phenotype correlations will have to determine whether morphologically distinct phenotypes can be correlated with specific mutations. For this purpose, cutaneous nerve bundles could serve as an alternative tool to help identify and classify subtypes in this heterogeneous syndrome.
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PMID:Infantile demyelinating neuropathy associated with a de novo point mutation on Ser72 in PMP22 and basal lamina onion bulbs in skin biopsy. 1131 84

Hereditary neuropathy with liability to pressure palsies is an autosomal-dominant disorder, classically characterized by recurrent mononeuropathies, associated with a deletion at 17p11.2, encompassing the peripheral myelin protein 22 gene. The typical clinical episodes of pressure palsy are usually noted for the first time during the 2nd or 3rd decade of life. We found only few reports in prepubertal children. We report a case of a 7.5-year-old child with muscle weakness and severe hypotonia associated with developmental gross motor delay. We suspect that bilateral peroneal nerve palsies after birth were the first episode of pressure palsy. Nerve conduction studies demonstrated slightly prolonged distal latencies with normal conduction velocity. Typical features of hereditary neuropathy with liability to pressure palsies with recurrent mononeuropathies were found in the father. DNA analysis revealed 1.5-Mb deletion at 17p11.2 in both father and child. To the best of our knowledge, this patient is one of the youngest ever found with this disease.
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PMID:Hereditary neuropathy with liability to pressure palsies in infancy. 1284 87