[Mitochondrial respiratory chain diseases. Evaluation and variability in 52 patients]. / Enfermedades de la cadena respiratoria mitocondrial. Evaluación y variabilidad en 52 pacientes.

INTRODUCTION: Clinical, electrophysiological, genetic and biochemical deficiencies variability were evaluated in 52 patients diagnosed of mitochondrial respiratory chain diseases (MRCD). PATIENTS AND METHODS: 26 men and 26 women, aged 19 to 79 years, were tested by clinical examination, electrophysiological techniques, muscle biopsy and genetic and biochemical studies. RESULTS: The patients were classified into seven phenotypes: myopathy, chronic progressive external ophthalmoplegia, progressive ophthalmoplegia plus ataxia, Kearns-Sayre syndrome, mitochondrial encephalomyopathy with lactic acidosis and stroke episodes (MELAS), myoclonic encephalopathy with ragged-red fibers (MERRF), and encephalopathies. Each phenotype may begin by different ways. The electromiography showed myopathy in 39 cases and various types of neuropathy in 10. Ragged-red COX negative fibers or widespread electron microscopic abnormalities were found in 47 cases. Simple deletions, multiple deletions and three different point mutations were observed. Deficiency of complexes I, II, III and IV were found alone or in different associations. CONCLUSIONS: MRCD shows wide variations in clinical, genetic and biochemical studies. Some patients with nonspecific manifestations, mainly of central nervous system, need careful attention and to be on account of diagnostic suspicion.

Enfermedades de la cadena respiratoria mitocondrial. Evaluación y variabilidad en 52 pacientes / Mitochondrial respiratory chain diseases. Evaluation and variability in 52 patients

Introducción. La variabilidad clínica, electrofisiológica, de las deficiencias bioquímicas y genéticas se evaluó en 52 pacientes diagnosticados de enfermedades de la cadena respiratoria mitocondrial (ECRM). Pacientes y métodos. Se evaluó a 26 hombres y 26 mujeres, de edades comprendidas entre 19 y 79 años, mediante exploración clínica, técnicas electrofisiológicas, biopsia de músculo y estudios bioquímico y genético. Resultados. Se clasificó a los pacientes en siete fenotipos: miopatía, oftalmoplejía externa progresiva crónica, oftalmoplejía progresiva plus con ataxia, síndrome de Kearns-Sayre, encefalomiopatía mitocondrial con acidosis láctica y episodios de ictus (MELAS), encefalopatía mioclónica con fibras rojo rasgadas (MERRF) y encefalopatía. Cada fenotipo puede debutar de forma diferente. La electromiografía mostró miopatía en 39 casos y diferentes tipos de neuropatía en 10. En 47 casos se puso de manifiesto la presencia de fibras rojo rasgadas COX negativas o alteraciones mitocondriales prominentes al microscopio electrónico. Se observaron deleciones simples y múltiples, así como tres mutaciones puntuales diferentes. Se encontraron deficiencias de los complejos I, II, III y IV aisladas o en diferentes asociaciones. Conclusiones. Las ECRM muestran grandes diferencias entre ellas en los estudios clínicos, bioquímicos y genéticos. Algunos pacientes con manifestaciones inespecíficas, principalmente del sistema nervioso central, requieren una atención cuidadosa y que se plantee la sospecha diagnóstica de ECRM (AU)

Introduction. Clinical, electrophysiological, genetic and biochemical deficiencies variability were evaluated in 52 patients diagnosed of mitochondrial respiratory chain diseases (MRCD). Patients and methods. 26 men and 26 women, aged 19 to 79 years, were tested by clinical examination, electrophysiological techniques, muscle biopsy and genetic and biochemical studies. Results. The patients were classified into seven phenotypes: myopathy, chronic progressive external ophthalmoplegia, progressive ophthalmoplegia plus ataxia, Kearns-Sayre syndrome, mitochondrial encephalomyopathy with lactic acidosis and stroke episodes (MELAS), myoclonic encephalopathy with ragged-red fibers (MERRF), and encephalopathies. Each phenotype may begin by different ways. The electromiography showed myopathy in 39 cases and various types of neuropathy in 10. Ragged-red COX negative fibers or widespread electron microscopic abnormalities were found in 47 cases. Simple deletions, multiple deletions and three different point mutations were observed. Deficiency of complexes I, II, III and IV were found alone or in different associations. Conclusions. MRCD shows wide variations in clinical, genetic and biochemical studies. Some patients with nonspecific manifestations, mainly of central nervous system, need careful attention and to be on account of diagnostic suspicion (AU)

Follow-up study after replantation of the forearm and nerves resuture.

OBJECTIVE: Clinical and electrophysiological evolution after total section of the forearm and nerves resuture. MATERIAL AND METHODS: A young boy aged 14 years with accidental amputation of the right forearm. The forearm was replanted within the first 6 hours after accident. Electromyography, nerve conduction, estimated number of the motor units, single fiber EMG and motor complex reflex responses were studied until 4 years after surgery. RESULTS: Functional recovery was reached in muscles innervated by median and ulnar nerves. After 4 years of evolution EMG showed signs of chronic neuropathy. Nerve conduction did not reach normal values. Single fiber EMG showed increased fiber density and jitter, and intermittent impulse blocking The estimated number of the motor units was severely reduced with high mean amplitude. Motor reflex responses were elicited by cutaneous stimulation consistent with axon reflexes or ephatic responses. CONCLUSIONS: Replanted limbs in selected cases and nerve's resuture may reach a functional recovery for daily activities.

Single fiber electromyography (SFEMG) in mitochondrial diseases (MD).

Conventional EMG, nerve conduction studies and SFEMG were performed in 18 patients with various phenotypes of MD. 14 cases showed findings consistent with mild myopathy, 2 patients signs of sensory-motor axonal neuropathy and 2 cases a mixture of myopathy and axonal neuropathy. Motor unit fiber density was mild increased in 8 out of 13 tested cases. Jitter was abnormal in 10 out of 18 tested patients. Jitter abnormalities were not related to myopathic or neurogenic features in the EMG study, and may be observed in muscles without clinical weakness. The results suggest the existence of neuromuscular transmission disturbances in patients with MD.

Neuralgic amyotrophy: variable expression in 40 patients.

This study looks at disease diversity, location of lesions, and progression of neuralgic amyotrophy (NA). Forty patients (28 male and 12 female, age range 15 to 70 years) were clinically examined. Muscle atrophy, weakness, and sensory impairment were assessed. Needle EMG and conduction velocities were performed. Careful clinical, electrophysiological, laboratory, and radiological studies excluded other illness. Twenty-two patients were followed for 2 years. Antecedent fever and upper-respiratory tract infection was seen in 22 cases. Pain of sudden onset was always the initial symptom, followed by weakness, mainly in the proximal muscles of shoulder. The affectation was bilateral in 7 cases. Seven cases had a recurrent form of the disease. Clinical and electrophysiological findings suggest axonal lesions of the peripheral nerves, occurring singly (mononeuritis) or in various combinations (mononeuropathy multiplex). Unusual features, such as VII and XI cranial nerves, phrenic nerve, and lateral antebrachial cutaneous nerve affectation, were found. Follow-up showed good function recovery at variable times, even in 1 case with associated myotonic dystrophy (MD). NA is a well-defined entity, with variable clinical expression and data consistent with mononeuropathy or mononeuropathy multiplex, axonal in type. The overall prognosis is good. The progression in a patient with MD suggests that the capability of muscle fiber membrane to accept regenerating nerve sprouts remains in dystrophic muscles.

Reinnervation of dystrophic muscles.

OBJECTIVE: To analyse the regenerating capability of the peripheral nerve fibers and the capability of the muscle fibers to accept the regenerating and new nerve sprouts in myotonic dystrophy (MD). MATERIAL AND METHODS: One male, aged 58 years, diagnosed of MD at the age of 30 years, suffered neuralgic amyotrophy in the right shoulder girdle 4 weeks before admission. Needle EMG and nerve conduction studies were performed on admission and 6, 12, and 18 months later. RESULTS: On admission there were atrophy and absence of voluntary contraction in deltoids, supra- and infraspinatus muscles. EMG showed abundant fibrillations, positive sharp waves and myotonic bursts in these muscles without voluntary activity, consistent with axonal neuropathy of both axillary and suprascapular nerves. The follow-up showed signs of reinnervation 6 months later and slight loss of long duration and high amplitude MUPs at 18 months of evolution, with good clinical recovery. This is compatible with chronic neurogenic atrophy, presumably as an expression of type grouping. CONCLUSIONS: The reinnervation capability of the nerve fibers and the capability of muscle fibers membrane to accept regenerating and new nerve sprout remain in MD. Myotonic bursts persist after total denervation.

Electrophysiological assessment in neurogenic thoracic outlet syndrome.

OBJECTIVES: To evaluate the value of different electrophysiological techniques in the diagnosis of neurogenic thoracic outlet syndrome (TOS). MATERIALS AND METHODS: Two females, aged 22 and 30 years, with progressive weakness and wasting of the right hand with slight sensory disturbances. Needle EMG, motor and sensory conduction along median and ulnar nerves, sensory conduction of medial (MACN) and lateral (LACN) antebrachial cutaneous nerves. RESULTS: Chronic neurogenic atrophy in small hand muscles, more severe in lateral part of thenar eminency, reduced compound muscle action potentials (CMAPs) more severe by median than ulnar stimulation, and reduced amplitude of the SNAPs of ulnar and MACN were the main findings consistent with neurogenic TOS. Both patients had right cervical rib in radiography. CONCLUSIONS: Electrophysiological study is useful in the diagnosis of neurogenic TOS. Reduced amplitude of MACN and ulnar nerve SNAPs, predominant denervation in thenar eminency, and reduced amplitude of CMAPs, more by median than by ulnar stimulation, are consistent with the diagnosis.

Spanish family with Machado-Joseph disease: neurophysiological features and neuropathy study.

OBJECTIVES: We have carried out electrophysiological studies and sural nerve biopsy evaluation in a Spanish family with genetically proven Machado-Joseph disease (SCA3/MJD) phenotype III. PATIENTS AND METHODS: Two symptomatic and other two asymptomatic members of the family were clinically examined. Electrophysiological evaluation included multimodal evoked potentials, quantitative electromyography and nerve conduction studies, and central motor conduction time. We also report neuropathological findings in the sural nerve biopsy in the proband. RESULTS: Analysis of the SCA3/MJD CAG trinucleotide repeat at the ataxin 3 gene in the DNA of the proband and one of his daughters demonstrated an expanded allele of 63 CAG repeat units. Ataxic pursuit was primary disturbed in MJD, followed by gaze evoked nystagmus, hypermetric saccades and glissades. Limitation of vertical and horizontal gaze, impaired sinusoidal vestibulo-ocular reflex and vestibulo-ocular reflex-fixation-suppression, and active and passive optokinetic nistagmus loss appeared at later stages. Evoked potential studies showed multimodal abnormalities. Electrophysiological and sural nerve biopsy findings correspond well to a pattern of both anterior horn and root ganglion cell distal dominant degeneration. Central motor conduction time was normal in our patients up to advanced stages of the disease. CONCLUSIONS: Electrophysiological and neuropathological studies suggested widespread peripheral and central affection in MJD. Repeated application of electrophysiological techniques may prove useful for monitoring disease progress.

Peroneal neuropathy after weight loss.

The objectives of this study were to evaluate the clinical and electrophysiological findings in peroneal mononeuropathies following a weight-reduction diet. Thirty patients with acute peroneal palsy and weight loss were studied. Complete nerve conduction studies (NCS) were performed in upper and lower limbs. NCS showed conduction block (CB) of the peroneal nerve at the fibular head that recovered in 29 patients within 3 weeks to 3 months. Severity of CB was correlated with clinical weakness. Three patients had abnormalities consistent with polyneuropathy (PNP). NCS in asymptomatic relatives confirmed familial neuropathy. Nerve biopsy and molecular study were consistent with hereditary neuropathy with liability to pressure palsies (HNPP). One of these peroneal palsies (6 months) recovered after neurolysis. Weight loss might be a risk factor in peroneal mononeuropathies. NCS is a tool in the diagnosis of the site and severity of the nerve injury. Testing should be considered for relatives of patients with PNP because peroneal mononeuropathies may be the first expression of HNPP.

Enfermedad de machado-joseph en una familia española: datos neurofisiológicos y estudio de la neuropatía / Spanish family with Machado-Joseph disease: neurophysiological features and neuropathy study

Objetivos: Se han realizado estudios neurofisiológicos y biopsia del nervio sural en una familia española con diagnóstico genético de enfermedad de Machado-Joseph (SCA3/MJD) y fenotipo clínico III. Pacientes y métodos: Se examinaron dos miembros de la familia clínicamente afectados y dos asintomáticos. El estudio neurofisiológico incluyó los siguientes estudios: potenciales evocados multimodales, electromiografía y conducción de nervio, tiempo de conducción motora central y otoneurología. Se realizó biopsia del nervio sural en el caso índice. Resultados: El análisis de la expansión del triplete CAG en el gen de la ataxina 3 de la SCA3/MJD demostró en el ADN del caso índice y de una de sus hijas una expansión alélica de 63 repeticiones. La presencia de un seguimiento ocular atáxico parece ser el primer signo oculomotor de la SCA3/MJD, seguido del nistagmo espontáneo, las sacadas hipermétricas y glissades. La limitación de los movimientos oculares conjugados verticales y horizontales, y las alteraciones del reflejo vestíbulo-ocular en la prueba pendular, de la supresión visual del reflejo vestíbulo-ocular y del nistagmo optocinético (activo y pasivo) se presentan en los estadios posteriores. Los estudios electromiográficos y de conducciones de nervios y los resultados de la biopsia del nervio sural concuerdan con un patrón de afectación degenerativa de las neuronas del asta anterior y del ganglio raquídeo. El tiempo de conducción motora central se mantuvo normal hasta estadios avanzados de la enfermedad. Conclusiones: El resultado de los estudios neurofisiológicos y los hallazgos de la biopsia del nervio sural sugieren una participación extensa del sistema nervioso central y del periférico en la SCA3/MJD. La valoración periódica mediante técnicas neurofisiológicas resulta útil para la monitorización del progreso de esta enfermedad. (AU)

Phrenic nerve conduction study in demyelinating neuropathies and open-heart surgery.

OBJECTIVES: The aim of this study was to determine normal values of phrenic nerve conduction (PNC) in healthy individuals; to evaluate the subclinical extent of phrenic nerve involvement in Guillain-Barré syndrome (G-B) and hereditary motor and sensory neuropathy-I (HMSN-I), and to evaluate phrenic nerve damage after cardiac surgery. MATERIALS AND METHODS: PNC was performed by transcutaneous stimulation in the neck and recording the diaphragmatic potential from surface electrodes placed at the seventh and eight intercostal spaces. PNC was performed bilaterally in 25 healthy volunteers and 25 patients before and after open-heart surgery. Right PNC was also performed in 5 cases with G-B and 5 patients with HMNS-I. RESULTS: Latency and amplitude of the diaphragmatic potential were the same in controls and in patients with cardiac disease before surgery. After surgery, 28% of patients had left phrenic nerve inexcitability, and 8% had reduced amplitude of the response. These 9 patients demonstrated elevation of the left hemidiaphragm on chest radiography. Left PNC performed 1 year after the operation showed improvement in latency and amplitude of the responses in all except one patient. PNC was prolonged in 4 out of 5 cases with G-B and in all patients with HMNS-I. CONCLUSIONS: PNC is an easy and reliable method in evaluating phrenic nerve damage due to hypothermia or primary stretch injury in patients after cardiac surgery. PNC may be helpful in detecting diaphragmatic involvement before clinical ventilatory insufficiency in demyelinating neuropathies such as G-B and HMNS-I.

Quadriceps atrophy after knee traumatisms and immobilization: electrophysiological assessment.

Automatic analysis of EMG (T/A analysis) and invasive muscle fiber conduction velocity in situ (MFCV) were performed in 15 patients after traumatic lesions of the knee and immobilization with quadriceps atrophy. T/A analysis showed transient reduced number of turns, consistent with inhibition of quadriceps motoneurons, that recovered within the first 2 weeks after the plaster cast had been removed. MFCV was significantly slowed and showed a gradual improvement, reaching normal values after 6 weeks. These results suggest that decrement in activated motor units may be the cause of the disproportionate weakness of the quadriceps muscle on the first days after immobilization by the plaster cast. The recovery of MFCV was related with functional improvement of strength after the first weeks.

Disability in multiple sclerosis. The role of transcranial magnetic stimulation.

Transcranial magnetic stimulation (TMS) was used to measure intensity threshold, conduction of the central motor pathways (CMCT) and amplitude of the motor evoked potentials (MEPs) in 50 patients with definite form of multiple sclerosis (MS), 31 females and 19 males, aged 15 to 58 years (mean 31.9 +/- 9.8). Abnormalities in at least one parameter after TMS have been found in 76% of the cases. Interside CMCT asymmetries increased the diagnostic yield to 86% of the patients. Three MS individuals with normal clinical examination have prolonged CMCT (silent lesions). There was significant correlation between CMCT and evolution of the disease, and with the degree of pyramidal signs. CMCT correlated with cerebral motor pathway, pons, and cervical cord lesions in MRI study. TMS is an easy and reliable method to quantify pyramidal and cerebellar dysfunction in MS and monitoring the evolution of the disease.

Motor hand recovery after stroke. Prognostic yield of early transcranial magnetic stimulation.

Transcranial magnetic stimulation (TMS) was performed in 20 patients within the first days after stroke. Motor evoked potentials (MEPs) were bilaterally recorded over thenar eminence muscles, and central motor conduction time (CMCT), amplitude of the MEPs (A%M) and threshold intensity compared between both sides. Six months later the patients were reexamined. Within the first days after stroke the obtention of MEPs at rest or during voluntary muscle activation have a favorable prognostic value. All patients with early response by TMS reached a good motor function in the following months. The follow-up showed that the electrophysiological improvement was closely related to clinical recovery of the hand function. However, even in cases with a good recovery, the CMCT and, mainly, the A%M, may be significantly different related to those in normal hand. TMS may be an early and valuable prognostic indicator of hand function recovery after stroke, and their prognostic yield is higher than clinical evaluation and CT study. TMS is a quantifiable method of motor disability and may have practical application in the management and rehabilitation therapy in stroke patients.

Muscle fiber conduction velocity in situ (MFCV) in denervation, reinnervation and disuse atrophy.

OBJECTIVES: Muscle fiber conduction velocity (MFCV) was performed in disuse atrophy, in denervated muscle and during reinnervation as a possible index of muscle atrophy, and to clarify the evolution of the fiber size. MATERIAL AND METHODS: MFCV was performed in 12 patients with complete denervation of biceps brachii muscle and during various stages of reinnervation. Twenty-one patients with disuse quadriceps atrophy were also tested. Invasive MFCV was performed according to the method reported elsewhere (2). RESULTS: MFCV decreased significantly in denervated muscles. Reduction of MFCV was found during the first weeks and was progressive. Peak frequency in histograms decreased and the normal Gaussian distribution was lost. MFCV increased progressively after reinnervation with coexistence of slow and significant increase of faster MFCV. MFCV decreased significantly also during the first weeks after immobilization and improved by rehabilitation therapy. CONCLUSION: MFCV is a reliable method to test the muscle fiber size after denervation and immobilization, and its evolution by reinnervation and therapy.

Central motor conduction in hereditary motor and sensory neuropathy and hereditary spastic paraplegia.

Conduction of the central motor pathways (CMCT) by magnetic stimulation of the motor cortex (TMS) was performed in 17 patients with hereditary motor sensory neuropathy (HMSN) and 2 siblings with hereditary spastic paraplegia (HSP). CMCT was prolonged in two patients with HMSN I with associated pyramidal features and in two subjects with HMSN II without clinical pyramidal signs. CMCT may be abnormal in HMSN due to central motor pathways involvement or altered spinal excitability with increased synaptic delay. CMCT was normal in the upper limbs in patients with HSP but increased in the legs. Diagnostic yield of TMS increased in less disabled cases with HSP when selective conduction at the spinal level (C7-S1) was calculated. Abnormal spinal conduction in HSP is consistent with degeneration of the crossed corticospinal tracts at the thoracic level found in neuropathologic observations.

Central motor conduction time in patients with multifocal motor conduction block.

The finding of conduction block (CB) within short consecutive segments along a motor nerve is a key feature of multifocal motor neuropathy (MMN). Despite their different pathogenesis, this may be the only clinical difference between some cases of MMN and the pure spinal muscular atrophy form of motor neuron disease (MND). In 12 patients with distal atrophy and fasciculations and electrophysiological evidence of CBs in the upper limbs, we measured the peripheral and central motor conduction times (PMCT and CMCT) to hand muscles. We reasoned that patients with MMN should show an abnormally prolonged PMCT with normal CMCT, whereas an increased CMCT would suggest MND. All patients had delayed F-wave latency and increased PMCT. Three patients had increased CMCT. Follow-up showed little clinical and electrophysiological change in 7 of the 9 patients with normal CMCT, and a progressive motor deficit leading ultimately to death in 1 of the 3 patients with increased CMCT. This patient's electrophysiological follow-up showed a significant decrement of the compound motor action potential to both proximal and distal stimulation points, with disappearance of earlier CBs. Autopsy revealed loss of anterior horn cells and axons of the ventral root, and degeneration of large myelinated fibers. We conclude that determining the CMCT may help in differentiating MND from MMN. Persistence of a stable clinical picture over a span of at least 1 year and lack of electrophysiological signs of involvement of upper motor neurons should both be required before establishing the diagnosis of MMN even with electrophysiological evidence of CB.

Transcranial magnetic stimulation in amyotrophic and primary lateral sclerosis.

Conduction of the central motor pathways after transcranial magnetic stimulation (TMS) was investigated in 7 patients with amyotrophic lateral sclerosis (ALS) and 1 case with primary lateral sclerosis (PLS). Threshold intensity, central motor conduction time (CMCT) and amplitude of the motor evoked potentials (MEPs) were evaluated. Threshold was abnormal in 85% of tested limbs, and CMCT prolonged and amplitude of the MEPs attenuated in 28.5% of patients with ALS. Abnormal CMCT was asymmetric and related to clinical score. MEPs were absent in lower limbs in PLS, with prolonged or attenuated amplitude of the MEPs in upper limbs. EMG showed widespread signs of lower motor neuron involvement in ALS, but not in PLS. Cranial MRI showed frontoparietal cortical atrophy, more marked in pre-central gyrus, and SPECT there was lower tracer uptake in the perirolandic area in the PLS patient. EMG examination, TMS, cranial MRI and SPECT can help in the diagnosis of PLS.

Early onset cerebellar ataxia and preservation of tendon reflexes: clinical phenotypes associated with GAA trinucleotide repeat expanded and non-expanded genotypes.

The aim of this study was to determine phenotypie characteristics of patients with early onset cerebellar ataxia (EOCA) with preserved tendon reflexes. The series comprises 25 patients, representing 10% of all ataxic patients who have been genetically studied in our laboratory since 1990. There were 11 males and 14 females. Fourteen patients were homozygous for the GAA expansion on chromosome 9q13 (group 1) and therefore a diagnosis of Friedreich's ataxia with retained reflexes (FARR) was given. The remaining 11 patients had two normal non-expanded alleles (group 2) and a working diagnosis of EOCA with retained reflexes (EOCARR) was established. Mean ages of onset were 13.7 +/- 5.9 years (3-25) for group 1 and 10.3 +/- 7.3 for group 2; the difference was not significant. Frequencies of symptoms and signs were also comparable for both groups the only significant differences being the higher frequency of nystagmus, cardiomyopathy and sensory neuropathy in group 1 patients. There was a tendency for FARR patients to have higher frequencies of hypopallesthesia in the lower limbs and skeletal deformities. In none of the cases diabetes mellitus was observed. We conclude that differentiation of FARR and EOCARR may be suspected by classical clinical and electrophysiological data and confirmed by analysis of the GAA repeat.

Clinical features and genetic analysis of a Spanish family with spinocerebellar ataxia 6.

OBJECTIVE: To present the clinical features and DNA analysis of a Spanish SCA6 family. MATERIAL AND METHODS: Four symptomatic members of the family (mean age at onset: 53.75+/-5.21) were examined. SCA6 CAG trinucleotide repeat was analysed in the proband by the polymerase chain reaction (PCR). RESULTS: Early dysphagia, ophthalmoparesis and neck dystonia in the oldest patient, without the loss of vibratory and proprioceptive sensation supporting the theory of phenotypic variability within families with SCA6. Our results are in accordance with the theory that the size of the repeat pattern correlates with the age at onset of the symptoms. Analysis of the SCA6 CAG trinucleotide repeat at the CACNA1A gene in the patient's DNA demonstrated an expanded allele of 22 CAG repeat units. CONCLUSIONS: This study identifies phenotypic differences in the surviving kindred. The diagnosis of SCA6 in family members or single affected patients can be made by direct molecular analysis. This makes predictive testing possible.