Biochemical and genetic characteristics of 40 neonates with carnitine deficiency / 中南大学学报(医学版)

OBJECTIVES@#Primary carnitine deficiency (PCD) is a rare fatty acid metabolism disorder that can cause neonatal death. This study aims to analyze carnitine levels and detect SLC22A5 gene in newborns with carnitine deficiency, to provide a basis for early diagnosis of PCD, and to explore the relationship between carnitine in blood and SLC22A5 genotype.@*METHODS@#A total of 40 neonates with low free carnitine (C0G (p.Y251C), c.495 C>A (p.R165E), and c.1298T>C (p.M433T). We found 14 PCD patients including 2 homozygous mutations and 12 heterozygous mutations, 14 with 1 mutation, and 12 with no mutation among 40 children. The C0 concentration of children with SLC22A5 gene homozygous or complex heterozygous mutations was (4.95±1.62) μmol/L in the initial screening, and (3.90±1.33) μmol/L in the second screening. The C0 concentration of children with no mutation was (7.04±2.05) μmol/L in the initial screening, and (8.02±2.87) μmol/L in the second screening. There were significant differences between children with homozygous or compound heterozygous mutations and with no mutation in C0 concentration of the initial and the second screening (both @*CONCLUSIONS@#There are 5 new mutations which enriched the mutation spectrum of SLC22A5 gene. C0<5 μmol/L is highly correlated with SLC22A5 gene homozygous or compound heterozygous mutations. Children with truncated mutation may have lower C0 concentration than that with untruncated mutation in the initial screening.

Comparison of Clinical and Electrophysiological Characteristics between CMTX with Cx32 Missense Mutation and CMT1A with PMP22 Duplication

BACKGROUND: Charcot-Marie-Tooth (CMT) disease is a clinically and genetically heterogeneous disorder. Connexin32 (Cx32) gene mutations on Xq13.1 cause the X-linked form of CMT disease, and PMP22 gene duplication on 17p11.2-p12 causes CMT1A. The aim of the present study is to determine the clinical and electrophysiological characteristics between X-linked CMT patients with Cx32 missense mutations and CMT1A patients with PMP22 duplications. METHODS: We screened for 17p11.2-p12 duplication, and for point mutations in Cx32 genes of 48 Korean CMT families. Both neurological examination and nerve conduction studies were performed in all patients. RESULTS: Frequency of CMTX (6.3%) in our study was similar to Japanese, and was lower than those in European peoples. CMTX patients displayed no man-to-man transmission, and had cranial nerve involvement. CMTX patients showed more wide range of motor and sensory nerve conduction velocities than CMT1A patients. We found one family with axonal neuropathy and two families with demyelinating neuropathy in CMTX patients. CONCLUSIONS: Our findings suggest that mutations in Cx32 are probably less frequent in Asian CMT patients than European patients, and CMTX neuropathy is intermediary between CMT1 and CMT2. In addition, inheritance pattern and cranial nerve involvement are useful in differentiating CMTX from CMT1A with duplication.

Charcot-Marie-Tooth type 1A Patient with a Novel Frame Shift Mutation (Ala106fs) in the PMP22 Gene

Charcot-Marie-Tooth disease (CMT) with hearing impairment is a clinically distinct rare entity described in a few families, usually with a demyelinating neuropathy. The molecular basis for this disease has not been established with certainty. Audiological evaluation has revealed auditory neuropathy in the affected individual. We report a CMT1A family with sensorineural hearing loss and a novel frame shift mutation Ala106fs (318delT) in the PMP22 gene.